New furnace\boiler options for our home

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  #1  
Old 01-01-14, 02:52 PM
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New furnace\boiler options for our home

Hello. This is my first post. I appreciate this forum and the opportunity to comment within it.

The reason I've come here is to get advice on replacing one or both of our 36-year-old Lennox G8 series natural gas furnaces which, amazingly, are still functioning well. (We also have a 36 year old John Wood natural gas water heater which, at least in part as a result of my replacing its anode every few years, is also still functioning well.)


First some background information.

We moved into our 1950-ft2, well-insulated, nearly-square bungalow (with 1950 ft2 mostly-finished basement) 14 years ago. Most significantly, in order to conserve natural gas (lower our bill) during a period of unprecedented high natural gas prices, 7 years ago we bought, and I personally installed, in our fairly large main-level TV room, a Rinnai 1004F, 38,400 BTU/hr, 80% AFUE, direct-vent natural gas heater. It vents to the outside environment via an amazingly small concentric intake/exhast. Neither the heater or its vent have ever caused us any trouble whatsoever.



I have never regretted purchasing the Rinnai. We set the theromstat on the Rinnai to heat our 9'-ceiling TV room to a very comfortable 76 F. There is an overhead paddle fan in the middle of the ceiling which circulates the air in the room to a uniform temperature. This sunken TV room has slightly above it our fairly large kitchen. The kitchen and TV room have no wall between them, so they are essentially one large room on two slightly different levels, so the Rinnai also keeps the kitchen nice and warm.

On the main level, off the kitchen, there is a dining room which leads to a pretty large living room, which has a large, floor-to-ceiling double-pane bay window that is probably ten feet wide. Also on the main level there is a master bedroom+en suite bath, a main bathroom and two spare bedrooms. Amazingly, even when the outside temp is -20 F, the Rinnai keeps these “peripheral” rooms at between 62 and 65 F while we sit bathed in 76 watching TV or eating in the kitchen. Of course the bedrooms and bathroom have their entry doors open at all times during the winter.

Normally, even during the coldest cold, the furnace for the main level never runs. Only when we have guests and we want the whole main level warm do we run the main-level furnace. For peace of mind, however, we keep that furnace's thermostat set at 60F just in case the Rinnai should fail which, again, it never has.

Again, 80% of our basement is finished with drywalled ceilings and walls and carpeted floors. The walls against the foundation have 3.5” fiberglass insulation. The furnace room has unfinished ceiling and about 13 feet of exposed concrete foundation wall. Two small storage rooms have about the same state of finish.

The basement furnace specifications are as follows:



The main level furnace specifications are as follows:



There are a total of four, 30”x9”, main-level return “grates” in walls near the floor. Two are in the living and TV rooms and two are in the hallway adjacent to the bedrooms and bathroom. The wall cavity, combined with sheet-metal-covered spaces between floor joists, route the return air back to the main-floor furnace.


There are a total of 12 in-floor, hot-air vents on the main level that are fed hot air by 5” diameter round metal ducts.

There are a total of 10 in-ceiling hot-air vents in the basement. These are fed by 5" round metal ducts. All of the basement's return air comes back to the centrally-located basement furnace through one large opening in the finished hallway wall, directly in front of the large return-air vent on the furnace itself.

There are so called “basket” style filters on both furnaces, which, depending on how much each furnace runs, about every two months – sometime much less frequently on the main-level furnace.

To make what I'm about to ask a bit easier, first of all, we don't have or need AC.

Second, the coldest month here in Edmonton, Alberta is typically January. Last January our home consumed just under 20 gigajoules of natural gas energy in order to maintain indoor temperatures as I mentioned previously and, in the basement, as I describe below. If my calculations are correct, this gives an average consumption of 25,500 BTU per hour. (If I'm way off on that, please let me know.)

Third, we keep the thermostat for the basement furnace set at 54 F during the very coldest months of the winter, just to have peace of mind that the pipes in the basement will not freeze.

Fourth, there is a 5 or 6” insulated, fresh-air duct that runs from an exterior wall to the return-air plenum of the main-floor furnace. I believe that this fresh-air supply could be used for new HE furnace(s).

Fifth, I have already determined that it would be quite easy for me to install one or two plastic vent lines either out the side of the house or even up and out the present 7” metal flue line to the roof, but this would require the replacement of our present water heater with somethng whose vent would not go up that same flue.

Finally to why I'm posting. At some point, almost certainly sooner rather than later, it will be necessary for us to replace one or both of our Lennox furnaces, as well as the John Wood water heater. I'm thinking that this coming summer would be a good time to do that.

I'm waffling back and forth between a do-it-all tankless hot water system with so-called hydronic air handler that would heat the house via the existing duct work, or going completely with “separates”, just as we have things now – two funaces and a hot water heater.

Part of my attraction to the do-it-all is one intake and one exhaust, but it “puts all our eggs on one basket”, if you will.

Over the years I've replaced the belts, cleaned the burners, pilots and thermocouples on our Lennox units, as well as done all the maintenance, including timing belt changes on our vehicles, so I'd like to do as absolutely much as I can in the installation and ongoing maintenance of whatever heating device(s) we choose. (Again, I installed the Rinnai heater, which required the installation of a new nat gas line to it. The inspector said I had done a good job on everything.)

I've studied the Goodman natural gas furnace installation manual and I figure that I could do much, if not all, of it myself, although I'd probably pay someone to create the transition between a new furnace and the existing plenum(s). I also think that I could do most of the installation of a tankless water heater with hydronic unit. Of course in either case I'd need building permits and, after installation, pre-operational inspections to determine that everything I've done is correct and up to code.

One thing I'd like some advice on is whether to go with two furnaces or one and, in the latter case, just have a zone damper between the main and basement systems. Considering our relatively low consumption of gas even durng the coldest months, I think replacing both furnaces with one should be given careful consideration, especially with the Rinnai still in service.

I believe that our present furnaces are both wildly oversized for our home. I think one or two far smaller units could heat our home very well, even without the Rinnai in service.

Anyway, I'd appreciate any advice on our situation.

While I'm at it I have one final question. Do you think that Goodman top-of-the-line HE furnaces that are presently coming out of their manufacturing faciltiy are well-designed, reliable units?

Thanks very much for the opportunity.
 
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Old 01-01-14, 03:21 PM
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Not having any experience with the new Goodman equipment, I can't comment on that.

Personally, if possible/practical I would stick with 2 systems. I don't like dual zoned warm air systems at all. I've never seen one which worked well consistantly.

I would strongly suggest you download & run a manual J heat loss calculation. Here's one I have used & been happy with: HVAC Software, HVAC-Calc for Heat Loss, Heat Load Calculations
For the cost, it is probably the best money you'll spend on your project.
 
  #3  
Old 01-09-14, 08:33 AM
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Will do on the software.

For now, though, I have some questions.

1. Has the reliability of IFC boards gotten better over the years since they've been introduced and, if so, what is the typical lifetime of a board in a 7-months-of-cold-winter climate? (Are boards designed for a certain number of cycles in their lifetime, or will a new board sitting on a shelf fail because of simple age?)

2. Who makes the most reliable board with the longest lifetime, or, like the myth of men, are all boards created equal?

3. When it comes to furnaces in general, is simpler better and, if so, as far as only reliability and cost of replacement parts goes, would single-stage with single speed circulating fan (if there even is such a thing) be better than two-stage, which, in turn, would be better than modulating with infinitely variable speed circulating fan? (Do any furnaces nowadays have circulating fans that operate only when the heat exchanger is withing a certain temperature range rather than continuously?)

4. I notice that Honeywell makes a so-called "universal" IFC board model S9200. This board supposedly replaces the OEM board on a variety of single-stage furnace makes and models. I also notice that there are some single-stage furnaces that are also high-efficiency. For the dedicated DIYr, do you think it makes economic and ease-of-repair sense to buy a model of furnace whose board can be replaced by the DIYr with either Honeywell's universal board or, if there is such a thing, another universal board?

5. Again, presently we have 2 old natural-draft furnaces and a natural draft water heater all venting up a 7" metal flue. Could/can 2 newer induced draft, mid-efficiency furnaces vent up the same flue?

Thans for any advice.
 
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Old 01-09-14, 06:45 PM
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Boards are a real crap shoot. I don't care who makes them or on what they are used. Some last for years & years some don't.

In my opinion, simpler is better. Certainly they are easier & far cheaper to repair. As far as I know, you can't buy a furnace today with a belt driven or single speed blower motor. You can buy single stage furnaces with a motor which only runs at a single speed selected speed. Most blower motors are at least 3 speed but only a single speed is used at a time. No furnace blower works on temperature anymore. They are all timed. The fan comes on X seconds after the stat calls for heat & goes off Y seconds after the end of the call for heat.

Furnace manufacturers are constantly changing thier boards. What is "universal" today, may not be tomorrow.

Not having a current copy of the National Fuel Gas Code at home, I can't answer the question about venting but my gut feeling is No.
Oops, just remembered you are in Canada. You would have to check Canada's code regarding the venting. It may differ from that in the U.S.
 
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Old 01-09-14, 08:41 PM
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Grady, thank you very much!
 
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Old 01-10-14, 07:25 PM
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Hope I've been of some help. Keep me posted on what you decide or if there's any other questions, I'll do my best to answer.
 
  #7  
Old 01-11-14, 02:34 PM
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Thanks for the offer, Grady.

The furnaces in our basement are not going to last forever, much as I'd like them to. So the question I must somehow finally answer is what furnace is going to be the least expensive and the least hassle to run and maintain over the long haul. I thought that would be an easy thng to figure out, but it definitely isn't.

We're happy with our old furnaces' present on or off operation, so we really don't care about maintaining a very narrow temperature range that some of the two-stage and modulating furnaces brag about.

Unlike vehicles, I have "experienced" relatively few furnaces in the relatively few homes I've lived in thoughout my 63 years of life. I have really never had a significant problem with any of them, especially the two old friends that are in our basement right now. They're like twin Energizer bunnies.

But our daughter and her husband's experience with their two older mid-efficiency Lennox furnaces has been the opposite of ours. Every two or three years the have to replace a board in one or the other and they're expensive. I'd like to avoid that, if at all possible and that's why I joined this forum.

What I'd like to have is a neighbor who just happens to have been my life-long best friend whom I trust more than my mother and who also just happens to have been in the residential furncace business for 40 years. I'd just pick up the phone and ask him "which furnace should I buy?", listen to his answer and that's the furnace I would buy.

But I don't have such friend and because you've made the offer, I'll ask the same question about induced-draft and circulating-fan motors that I asked about IFC boards. In terms of reliability, do some motor models stand head and shoulders above others, or, like IFC boards, are all men (fan motors) created equal?

I'm particularly interested in the long-term reliability of the so-called ECM-design motors that are described here:
Electronically Commutated Motor (ECM) - Canadian Centre for Housing Technology
Of course they sound wonderful, as do HE furnaces in general, but I think the cost of ownership ultimately comes down to a combination of efficiency PLUS reliability. I'm sure you know what I mean. Having to replace a board or an even more expensive motor in a HE furnace every few years may very well cancel any savings in reduced natural gas consumption over a less-efficient but more reliable furnace that consumes more gas.

If one decides to operate an ECM motor continuously, is that motor's lifetime in hours of operation greater or less than one which operates when heat is being demanded (burners are on) and then turns off until the next demand?

I asume that the heat exchanger in a modulating furnace remains hot to hotter most of the time. Does the heat exchanger in a modulating gas furnace last longer than the heat exchanger in a single-stage furnace?

Thanks again, Grady.
 
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Old 01-11-14, 03:36 PM
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I don't trust the ECMs having had to replace several, seeing how much they cost (between $600 & 1200), & if the control part has to be replaced, it has to be programed for your particular model of furnace.

As far as reliability, I haven't seen any one brand of furnace or motor any better than any other but there are some furnaces below averge. The ones which come to mind in that area are anything made by Nordyne or Goodman.

You are correct in presuming the heat exchanger of a modulating or two stage furnace would stay "hot" longer with fewer on/off cycles.

The true cost of ownership comes down to the sum of: Purchase price + energy cost, + repairs & maitenance.

The new equipment is not made with metal as heavy as the old stuff & therefore less tolerent of insuffient duct work.
 
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Old 01-11-14, 05:12 PM
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Thanks very much again, Grady!

Although I'm comfortable at this moment considering my options, when it comes right down to actually buying something, I suspect that I'm going to feel either like a (smart) lamb going to slaughter, or a shop-owner being offered health insurance by Al Capone.

I'm intrigued by your last comment about newer heat exchangers being less tolerant of insufficient duct work. I assume you mean that it is more important that the hot-air ductwork be of a minimum capacity so that the circulating air flow is adequate to cool the heat exchanger. Please tell me if I'm wrong on that.

But is there any downside to the hot air ducts being oversized? For example, let's just assume for the moment that our basement ductwork is properly sized for our present furnace's output of say 72,000 BTU and say 1200 cfm. Would a new furnace whose highest output is 50,000 BTU at 800 cfm be negatively affected by the old, now oversized, ductwork? The reason I ask that question is two fold.

First, the people who originally had our house built knew what the basement room layout was ultimately going to be, but, presumably for financial reasons, they didn't finish the basement until years after they moved in. Therefore, I believe our present basement furnace and ductwork was installed before the basement was insulated and finished years later. Because the basement furnace now runs infrequently even during the coldest winter months, I believe the basement heating system may be oversized to maintain a temperature of 70 F. If the heat-load software confirms that, I'd like to install a lower-capacity furnace and not alter the ductwork. In that case the ductwork may be oversized for the furnace (if it is even possible that ductwork can be oversized).

Second, if the present ductwork is now undersized for a modern furnace that has the same capacity as the old furnace, I'd really rather not tear apart the basement in order to install different-sized ductwork. Instead, I'd prefer to buy a furnace whose size would be proper for the present ductwork -- the reverse of what one would normally do -- and if that means a new furnace would have to run continuously to maintain the basement at 60 F instead of 68 F during our coldest days of winter, so be it.

So, again, is it OK to operate a new furnace with oversized ductwork? Would it be bad for a furnace to operate continuously (burners on) to maintain room temperature, or, because there would be fewer hot\cold cycles, would that actually be a good thing for the heat exchanger?

Thanks again.
 
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Old 01-11-14, 07:15 PM
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The only downside I know of with oversized ducts is the air being lazy & not having much throw from the registers. That being said, all furnaces have a temperature rise spec range. That range can be anywhere from 30-50 degrees (F) to 60-80 degrees. If the ducts are grossly oversized and the fan can't be slowed enough to meet the temp rise spec, supposedly it can cause damage to the heat exchanger (condensation?). Honestly I doubt the ducts would be so oversized as to cause a problem.

I also can't believe running a furnace constantly would hurt it since if the furnace is sized properly to the house, on a "design day" the furnace should run full time to maintain the designed indoor temps.

I know exactly how you feel about making the purchase.
 
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Old 01-11-14, 07:48 PM
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Thanks! I appreciate it.
 
  #12  
Old 01-19-14, 04:32 PM
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Well, a new turn of events.

As I was walking by the basement furnace I smelled a hint of gas. I removed the front upper panel and used my nose to determine that there is a very slight leak of gas around the stem of the slector knob. In short, I removed the valve and I'd like to replace it before our present above-freezing weather goes bye bye and old frigid man winter blasts in again.

Here is the General Control B57RBA601 gas valve that has served us well,


the outlet end view,

and the view of the vent line end, pilot and thermocouple, in that order:


I'm considering replacing the valve with a Honeywell VR8200H mentioned in the following pdf:
http://www.forwardthinking.honeywell...ll/68_0046.pdf

I'd appreciate hearing whether this is an appropriate valve. I'm a bit concerned that there is apparently no vent line on the Honeywell. What does that vent line do, anyway?

If you think there is a better replacement valve than the Honeywell, please tell me what it is.

BTW, I know that our furnace is old. I'm just trying to keep it chugging along until spring, when, as I said earlier in this thread, I will try to replace it myself with a new unit.

Thanks for any advice.
 
  #13  
Old 01-19-14, 05:48 PM
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Consider a humidifier for your basement furnace. A criticism I have with direct vent furnaces is there is no humidifier option I know of.
 
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Old 01-19-14, 06:33 PM
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The 8200H would work well for you IF the end to end dimention is right & you have room to swing the valve while installing.

Regarding the humidifier: No way, no how would I suggest putting a humidifier on a furnace. They generally do more harm than good. I probably remove 10 for every one I install. If you need extra humidity, use a free standing humidifier.
 
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Old 01-20-14, 04:15 AM
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"They generally do more harm than good." I have had no trouble with my Aprilaire. What is the problem people are having with humidifiers?
 
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Old 01-20-14, 07:43 AM
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Thanks for the advice, guys.

As you can see from my original photos, there is a drum-type humidifier on each furnace, but I long ago took the one on the basement furnace out of service because, first, it does not run that frequently and, second, I think keeping the humidity in the basement low is a good idea to minimize condensation against the outside walls of the basement.

As I said previously, the Rinnai direct vent heater heats the main level the vast majority of time, so even though the main-level furnace is technically in service, because the Rinnai has been so reliable, it has not yet run at all this year and this year has already been a long, cold one.

The Rinnai has a water tray underneath the front, which is filled through a small door that swings open. The discharge of the heater is directed across this tray, evaporating the water. (I have had to remove scale from the metal tray only once since we have owned the heater. No big deal.) During very cold weather I fill it with about 3 litres of water twice a day. The humidity in the main level stays right around 40%, even in the coldest weather (which causes considerable condensation on some of the colder windows, but we're willing to live with that rather than turn into mummies).

Anyway, the overall length of the new valve body is about 1/2" shorter than the old one. Because the iron gas line leading to the furnace sort of just flops in the breeze to a certain extent (when it's not connected to the furnace valve), I've tried giving it a bit of a nudge toward where the new valve will be and I think that a combination of this, perhaps sliding the furnace a fraction of an inch toward the gas line, and maybe not tightening the two sides of the valve to extra-tight will allow safe installation of the valve.

Specifically with regard to tightening things, with some thread dope applied, how loose can NPT threaded connections be and still be acceptably tight? I know there is a certain amount of leeway allowed, but I'm not sure exactly how much is too much.

Thanks again.
 
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Old 01-20-14, 02:35 PM
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Success!


To compensate for the shorter body on the new valve I bought a nipple that was 1/2" longer than the old one. Perfect fit and my nose tells me there is no gas leak anywhere with supply valve open.

In order to screw the valve onto the manifold line, I had to remove the manifold assembly from the furnace. No big deal and I had the opportunity to knock a bit of dirt out of the burners.

Getting the pilot line up on top rather than on the end the way it used to be was a bit of a PIA, but with a bit of creative routing I finally got the thing into the valve.

I then installed one thermostat wire and one blue wire on the TH/TR terminals on top, and the other thermostat wire on the TH terminal, and other blue wire on the TR terminal, on the side. Voila and ready to test.

The old thermocouple worked just fine right off the bat. I held the red button down for just a few seconds during and after lighting the pilot and the pilot continued to flow after lifting up on the red button. The selector then slipped right into the "on" position.

I can tell that the quality of construction of the new unit is inferior to the old one, but all the thing has to do is last until spring or summer and I'll be happy.

With tax included the valve cost us $130 and the nipple an additional 90 cents. Besides filters, I can't remember the last time we had to spend some money on Reliable #1. I think it was a belt maybe 8 years ago, so I'm not too concerned that this expenditure will be money down the drain when the unit is replaced. At that time maybe I'll remove the gas valve for somebody else to possibly use.

Driving to get the valve and installing it took a total of maybe three hours of my retired time. Very well worth it, IMO.
 
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Old 01-20-14, 04:55 PM
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Looks like you did a good job. I do suggest picking up some leak "soap" & checking all the fittings, including the pilot tube. Even if the leak detector is listed as "non-corrosive" I suggest wiping the excess off with a wet rag then on the pipe threads , rinse well.

Geo8rge: Nearly every humidifier I've seen on a furnace has caused ducts to rust or the worst cases, rusted out the heat exchanger. With standing pilot furnaces the problem usually isn't as bad due to the constant heat from the pilot.
 
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Old 01-20-14, 05:48 PM
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Will do on the soap solution. Thanks for the reminder.
 
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Old 01-25-14, 03:09 PM
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Before I made the first comment on this thread I called our neighbor to find out what furnace he had bought 3 years ago.

He said he had bought two HE furnaces (one for basement and one for first and second floors) and a HE water heater. I asked how the intake/venting was done and he said that the installers had "run everything up the old metal flue".

Today was my first opportunity since that conversation to have a good look at his roof and take what I think is a great photo of what comes out of his old flue.

I figure the distance from the neighbors basement up through the roof over the second floor must be close to 30 feet.

Because I think we have the same size flue, I'm thinking about doing the same thing, and on our bungalow with it's gently-sloping roof, installation should be a breeze compared to what the installers must have gone through with our neighbor's. I figure our pipes would be ten feet shorter.

Could someone take a stab at what is shown in that photo? Specifically, are the pipes with the elbows intake or exhaust? (I'm thinking they are intake because there are only two of them, versus three straight pipes which would be exhausts for the three appliances. The water heater must take its intake air from inside the house, but maybe I'm wrong on that.)

Anyone gone this route and, if so, how do you think it compares to the out-the-side-of-the-house routine? One potential shortcoming that I can see is if any of these lines were to get plugged, it's going to be a bear to get them open, especially when it's -40 C. But the installers are local and must be familiar with any potential shortcomings, I would hope.

Thanks.
 
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Old 01-25-14, 03:33 PM
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I too believe the pipes with the U bends are intake, if not, they should be. It may be an optical illusion but it looks like the exhausts are larger than are the intakes. Usually that is a no-no.

I've used the old metal chimney on a mobile home. The furnace manufacturer has a kit specifically for the purpose. I've also used a masonary chimney as a chase. No problems with either application.
 
  #22  
Old 01-25-14, 05:44 PM
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Grady, thanks very much again.
 
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Old 01-25-14, 05:46 PM
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Glad to help. Keep us up to speed on your progress.
 
  #24  
Old 02-10-14, 12:01 PM
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I've always been curious about just exactly how much our basement's Lennox G8-90-1 runs during cold weather, so yesterday afternoon I connected an old, small analog-movement, bedroom-table clock in parallel to the circulator fan motor.

I set the clock at 12:00 and put the furnace back into service. Sure enough, when the fan motor was energized, the clock's second hand started moving. When the motor stopped, so did the clock.

To make a short story shorter, over the next 16.5 hours the outside temperature fell from -2F to -16F and the latter held for the last 5 hours.

The basement thermostat was set at 63F, with the furnace coming on at about 62F and turning off at about 64F. The typical time it took the furnace to raise the temperature from 61 to 64 was about 9 minutes (0.15 hours).

During the entire period the furnace ran a total of 4.7 hours, so about 28% of the 16.5-hour time period. 28% of each hour would be just under 17 minutes of each hour.

Depending on the manifold gas pressure, the basement furnace is spec'd at 81,000 to 90,000 BTU/HR input and between 64,800 and 72,000 BTU/HR "bonnet capacity BTU/HR".

I really don't know what the real-world efficiency of the 36-year-old, natural-draft furnace is, so it is difficult for me to draw any firm conclusions from the above observations, but I think some reasonable guesses can be made.

First and foremost, whatever the real output of the furnace is, because it only runs 28% of the time in pretty cold weather when the thermostat is set at 63F, the furnace is wildly oversized for those conditions. (I'm now going to set the thermostat to 70F with the outside temp still at -8F and see how much the furnace runs.)

Second, assuming the actual efficiency of the furnace is say 70%, the output of the furnace would be between 45,360 and 50,400 BTU/HR and, again, because the furnace only operates about 28% of the time, this output is wildly oversized for the test conditions. 28% of output from a 50,400 BTU/HR furnace equals 14,112 BTU/HR from a furnace rated as such outputting for the entire hour (continuous operation).

Even IF the present furnace were 100% efficient, 28% of 90,000 BTU/HR would be 25,200 BTU/HR. That is, a 25,200 BTU/HR-output furnace would do the same running continuously.

Third, because our Rinnai (model 1004F, 38,400 BTU/hr, 80% AFUE, 360 CFM) direct-vent natural gas heater is able to maintain the temperature of the main level of our 1950-square-foot bungalow at 62F in the peripheral rooms and 76F in the TV room where it is located, I believe that the smallest two-stage furnace on the market will be more than adequate to keep our basement at between 63 and 70F in the coldest weather possible for our area. Even in that case, I very much doubt that a 2-stage furnace will ever get out of first-stage mode (except to raise temperature quickly to a new set-point).

BTW, while I'm at it, I've just been thinking about our neighbor's roof-top vent set-up as shown in the photo in a previous post. Does having all of those intakes and exhausts for three appliances so close together meet code (even in the US)?
 
  #25  
Old 02-10-14, 03:43 PM
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Without having any reference material handy I'm obviously guessing on your neighbors venting system but my gut feeling is it would be legal. I recently did a dual furnace job & the venting spec on them was the vents had to be something on the order of they must be either within 12" of each other or separated by at least 3'. If this was a manufacturer's spec or from the National Fuel Gas Code, I don't know.

Sure doesn't take much heat for that basement. You must be well insulated & sealed.
 
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Old 02-13-14, 03:47 PM
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Thanks for the comments, Grady.

Just thinking out loud in this post.

Because the heat load in the basement is so small, I'm really starting to lean toward a single furnace for the entire house, and perhaps not bother with zoning the basement at all, but treating it as just another "branch" of the main-level system, and perhaps make just an intial damper adjustment to "balance" the system such that the basement would get only enough output -- say 15,000 BTU/Hr -- to keep the basement at 63F even during our coldest weather possible.

The 31,000 BTU/Hr-output Rinnai maintains conditions upstairs as I described above (and the Rinnai is NOT running at maximum output to maintain 76F in the TV room in which it is located, even during our coldest weather, but to be conservative, for the moment I will assume that it is).

Therefore, basement load of 15,000 BTU/Hr + main floor load of 31,000 BTU/Hr = 46,000 BTU/Hr total load/loss.

Again, in January 2013 our home consumed just under a total of 20 gigajoules of natural gas in order to maintain indoor temperatures as I mentioned previously. If my calculations are correct, this gives an average (continuous) consumption during the month of 25,500 BTU per hour, so my total estimate of 46,000 BTU/Hr load/loss is quite conservative, leaving plenty of spare BTUs for any eventuality, except furnace outages, of course.

Considering all of the above real-world observations and consumption data, I believe that it is almost certain that one of the smallest two-stage furnaces on the market (for example Goodman's 46,000/32,000 BTU 95%, two-stage) could heat our entire home, including whatever temperature we want in the basement, even in the coldest weather. And it is also almost without doubt that the present ductwork in the two systems, combined with proper adjustment of a new, small furnace's circulator fan speed, will be more than adequate to maintain an optimal temperature rise in a new furnace. My one and only concern would be keeping the temperature on the combustion side of the heat exchanger high enough to prevent condensation in the primary heat exchanger, while at the same time having reasonable flow coming out of a total of 22 hot-air registers.

My recent test with the clock has taught me that there's nothing like real-world, in-situ testing, so what I'd really like to do now is determine if the basement furnace can heat the whole house. I am almost certain that it can while still not operating continuously. But how could I do that without major modifications to the ductwork?

Combining the return air systems would be no problem. The house is pretty much an open concept, except for the bathrooms and bedrooms, so for the period of the test we could just leave all interior doors open upstairs and let the return air flow downstairs via the large open stairwell to the basement and into the furnace room where all of the basement return air passes into a single large return-air plenum that is attached to the furnace.

But how do I get the output of the basement furnace also into the main level system without really tearing apart the output duct systems? That's the most difficult part, especially in the cold weather when I'd like to do the test. For now I'll just keep scratching my head and hope some brain cells get stimulated enough to produce an easy solution.
 
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Old 02-13-14, 04:21 PM
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Unlike most houses, your ductwork is going to be grossly oversized. The contrary is what is normally found. I don't know if you could "line" your existing ducts with flex or not. Doing so would certainly increase the static pressure & get you some more velocity out of each register.
Careful with that head scratching. You'll end up with a bald spot or worse.
 
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Old 02-14-14, 09:52 AM
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I'm still scratching. No hole yet.

What suddenly hit me (after scratching for a bit) before my last long post was what the basement furnace could have been heating in those 43 minutes of each hour that it did not run -- that is, the period of time "between" the demands for heat.

To elaborate, if each time the furnace shut down I had been able to simply flip a switch that would instantly have exchanged the basement furnace for the main-level furnace, turned it on and had it pour heat into the main level for the next 43 minutes and, then, back to the basement for 17 minutes, etc., what would have been the result? Again, I am almost certain that it would have heated the whole house.

That main-level furnace may in reality be just an oversized emergency backup unit that maybe we could somehow keep in some configuration for that purpose only, without having to buy a second new unit. (If the new unit fails at -30 in the middle of the night, I imagine manually operating one or more big dampers or sliding some pieces of sheet metal into, or out of, position in order to quickly get the old unit into service -- that kind of thing).

OTOH, in case the new furnace fails, we still would have the Rinnai available for service on the main level, and if the heat load in the basement is as low as I think it is, three small, portable, fan-driven 1500-watt electric heaters (about 500 BTU/Hr output each) could maintain 60 or above in the basement during the coldest weather. So maybe we don't really need a back-up furnace at all.

About the velocity of hot air coming out each vent. Again, we have 5"-diameter round ducts that feed each of the grand total of 22 heat registers of both systems. I've done a bit of searching and I believe that the ideal flowrate from each of these should be between 50 and 80 cfm. (The Rinnai outputs a max of 350 cfm, so 50 to 80 cfm for each of the registers in every room seems fine to me, particularly in our bedroom -- a place we don't want to hear "Dixie" being whistled in the middle of the night.) Therefore, to supply 22 of these, the furnace should output between 1100 and 1760 cfm. Again, the smallest 2-stage furnaces can do this easily.

The question that must be answered is if a furnace that has the specs of say the smallest Goodman 2-stage is operated in our house at its full output of 1200 cfm, will the temperature in the combustion/exhaust gas be high enough to prevent condensation in the primary heat exchanger?

To answer that question I need to know exactly what manufacturers mean by the term "variable speed" circulating-air blowers. Does "variable" in a 2-stage furnace mean that the fan speed can change (vary) during operation, or does it mean that fan speed can be adjusted between various speeds at intial set-up and it remains that way all the time? That is, when a 2-stage furnace is operating in the lower input/output stage, does the circulating fan speed also decrease, or does fan speed remain the same in both high and low modes? If it does remain the same in both modes, I could easily imagine that the combustion gas temperature must be lower in low mode than it is in high mode and, depending on how low it goes, condensation may occur in the primary heat exchanger -- not a good thing in a regular-steel primary, I understand, partcularly one that has those "crinkles" in its curves, as the Goodman and others do, where water might collect and cause corrosion.

While I'm at it, in a typical 2-stage furnace, does the induced draft fan speed remain constant in both low and high modes? I imagine that that would greatly affect combustion/exhaust gas temperature as well.

Still scratching..............
 
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Old 02-14-14, 12:58 PM
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What everyone is trying to get at with the velocity idea is the duct work sizing. Not worried so much about what the registers can put out. But for example if you have a duct system designed for 2,000 CFM at 800-900 FPM in velocity and you cut that in half and run a system putting out 1,000 CFM,you will be looking at a velocity of 400-450 FPM. It's like blowing through a straw and then blowing through a 3" pipe. You may have some balancing issues and worse, heat loss if your ducts are located in unconditioned spaces. The velocity helps the heat get where it was designed to go.

Most furnaces i have recently studied have either a two speed inducer motor.
 
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Old 02-14-14, 03:24 PM
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Might want to recheck your btu/watt calcs. 1500 watts will give you about 5100 btu.

What ever you do, stay away from the ECM blower motors. When they work, they're great but when they don't, you'd best have deep pockets. You can buy a whole furnace for what a motor costs (no exageration).

I think most blower motors run at a fixed speed in both high & low fire. Low fire is normally somewhere in the 65% range of high. If things are set up right, you will be toward the low end of the temp rise range in low & near the upper end on high.
 
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Old 02-15-14, 08:29 AM
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Grady, yes, I should have added another zero to 500, so three 1500-watt heaters would provide about 15,000 BTU/Hr to the basement. That will be enough to maintain at least 60F in the coldest weather.

As far as I have been able to tell, what you say is what I suspected about the typical, non-ECM "variable" speed blower motor. I assume that when the furnace is finally installed, it is fired up and air temperatures are measured in the return air and the hot-air plenum. If both ends of the rise are not what they should be, the speed of the blower motor is then adjusted, correct?

RDSTEAM, thanks for the input. I think I understand what you are saying about the duct-work.

Keep two things in mind about our situation. First, we live in an "open concept", almost-square bungalow that consists of a main level and a finished, mostly-insulated basement -- not a multi-story dwelling where getting heat to distant rooms can be a problem. Second, what's truly remakable is that we've had a long cold winter so far this season, some of which has been -22F, yet the furnace for the main level has not run once this winter!. The 1950 sq-ft main level of this house has been heated by a single Rinnai direct-vent "furnace" (pictured and described previously in this thread) that blows out a maximum of 350 cfm of heated air from only ONE 24" x 4" register near the floor of our TV room. That's "it" for the main level. And as far as I can tell, the Rinnai has never run at full output! (I know that because I've set its thermostat at its highest level and observed the remarkable output and sound of the thing in that mode.)

What happens now (with the Rinnai NOT in service) is either the basement or main-level, or both, thermostats call for heat. On come the furnaces and they blast away for a few minutes and then shut off. While the furnaces are running, hot air pours out of the registers. It's been this way since the house was built and the situation is actually fine with us, but those furnaces are going to have to be replaced at some point in the near future, and this is why I started this thread. Exactly WHAT should I do? -- is the question.

(Our neighbors answered that question 3 years ago and it cost them $15,000. Last week they left for a vacation and they asked us to look after their 2-story house, which included walk-throughs. We went over during a particularly cold day and, naturally, I examined their two new Lennox HE furnaces. Very impressive set-up, but I immediately noticed that neither furnace was running, even though the house was warm. I stood there for the next 10 minutes or so taking pictures and examining everything, yet the furnaces still did not come on. I can't help but think that there is some severe BTU-overkill going on next door.)

I have determined that the heat load in our basement is so low that it seems ridiculous to buy a furnace for the basement that will almost certainly be oversized. The lowest-output furnace I have found is a single-stage Napoleon 30,000 BTU unit and even that is too much. During the coldest part of the winter it is going to cycle just as the present unit does.

Rather than continue with the present situation with two new furnaces, I would prefer a single two-stage furnace that runs continuously in either low or high mode and pumps less volume of either warm air or even-warmer-air out of each register all the time during the cold part of our six to seven month winter. That's what I'm shooting for – continuous operation in pretty cold weather (stage 1), as well as continuous operation in the coldest weather (stage 2).

The situation I do not want to fall into, as many others apparently have, is buying a furnace that has too much output (either BTU-wise or CFM-wise) for the 5" duct-work that we have at present.

I know with near-certainty that a 46,000 BTU output furnace will heat our house in the coldest weather. Therefore, whatever the design of the duct-work is, as long as that duct-work allows full, unrestricted output from the furnace (both BTU-wise and CFM-wise) the furnace is going to eventually heat this bungalow. The energy isn't going to disappear.

In our house the duct-work is located mostly in the confined space between the drywall on the basement ceiling and the main-level floor above it. I really don't care if the duct-work loses heat to that space because, again, the heat energy will not lost. It will heat either the upstairs floor or the basement ceiling drywall, or, in the case of the exposed duct-work in our furnace room, the air in the furnace room itself, which I want to heat anyway. So, regardless of where the heat loss occurs, the lost energy will heat the air in either the basement or the main level above it and that's fine with me.

As that small space above the drywall ceiling gets heated and the temperature there approaches that of the air inside the duct, the rate of heat loss from the hot air inside of the duct to the outside space will decrease.

To put it simply, I don't think that we're ever going to have cold air coming out of any registers while the furnace is running – at least, not for more than just a few seconds. It'll probably be a situation similar to what we've got now with our kitchen hot-water tap where we get cold water for probably 20 seconds before the hot water from the tank finally makes its way to the tap. Even though our present furnaces are wildly oversized, after their blowers start we still get a few seconds of cool air before the warm air comes out.

I believe that as long as the hot air leaving a new furnace has an unimpeded route into every room, every room will eventually get heated. There is some variation in the length of each spine and each 5" duct. Therefore, the air temperature out of each register will likely be slightly different, and because of that, so too will the final temperature of each room (especially if that room has two outside walls). The only question is whether those temperatures will be close enough to each other so that the thermostat does not have to be constantly adjusted to suit someone's personal taste -- a battle of wills, so to speak. But more often than not there are some very low-tech solutions to these problems. For example, before we acquired the Rinnai, if we had guests and we did not want to turn down the thermostat at night, we would simply put a book over our bedroom register to block some or all of its output in order to lower the temperature of the room for a more comfortable sleep.
 
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Old 02-15-14, 09:22 AM
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That is correct except the actual temps are not important other than that of the max outlet temp. The difference is what you need to be concern with. It is rare not to be able to meet minimum temperature rise spec but once in a great while we will have to restrict the return volume to do so.

Are you looking at 2-stage 80% or 90%+ furnaces? In either case, inquire as to whether or not the venter & circulating fans increase their speed when going into high fire.

I've only installed couple of 2-stage furnaces & that was a bunch of years ago so I don't remember exactly how the circulating fan operated on them. One would think, with all of the technology today, manufacturers would use supply & return sensors & adjust the fan speed to meet temperature rise specs with a simple algorithm but nobody, to my knowledge does it residentially.
 
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Old 02-15-14, 10:22 AM
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Thanks, Grady.

I think I understand what you are saying about meeting minimum temperature rise and I will keep it in mind as I shop.

About the speed of circulating fans ......... are there fans that vary in speed during operation that are NOT ECM-design? If so, are they as expensive to replace as ECM and do you recommend them?

We are looking at around 95% furnaces -- those that allow plastic exhaust pipes. Because I'm now more inclined to go the one-furnace option, I will be able to route the intake and exhaust pipes out the side of the house, rather than go up the present metal flue. This way, when we replace our old water heater, we can do that with a natural-draft unit that requires a metal vent like our present unit does, rather than get a replacement that has an induced draft fan that requires 120V and, eventually, a replacement motor. Additionally, we want to have hot water even during a power outage.

I agree with you about the variable speed blower. Those ECMs are so expensive that it's surprising that no equivalent mechanical alternative has arisen. For example, with automotive CVT technology being so advanced nowadays, you'd figure that something similar, but much much smaller, might have been developed to control the fan speed. That is, the fan motor would run at one speed all the time, but a small CVT between the motor and fan would control the fan speed infinitely according to whatever operational criteria one wishes to set.

BTW, our Rinnai has a fully modulating gas valve and an ECM circulating-fan motor. Right now output is so low that I can barely hear the thing running, but heat is coming out of its vent. It maintains a very stable room temperature and that is very nice, indeed. But I would imagine that when, not if, those devices finally have to be replaced, those parts and the IFC board are going to require, as you say, deep pockets. I'm not looking forward to it.

What do you think of the new Armstrong-brand furnaces with their clamshell-style, stainless steel (SS) primary heat exchangers, as they describe very nicely in the following propaganda?
https://www.youtube.com/watch?v=nICi4CeZki0
Unfortunately, both of their HE models that have a SS primary, also have ECM motors, so they're probably "out" for us.

Are there any other furnace brands out there that have a SS primary heat exchager, but do not have ECM motors?

Thanks again.
 
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Old 02-15-14, 12:37 PM
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There certainly are multi-speed blower motors & every furnace out there, excepting those with ECMs, has one. They are readilly available, cheap, & easy to replace. Speed control is the key question. In a two stage furnace do they use, for example, low speed on low fire & kick it up to a higher speed on high fire? My answer to that is: I don't know.
 
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Old 02-15-14, 01:56 PM
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Thanks, Grady.

As I contact dealers, I will ask if the non-ECM blowers on 2-stage furnaces change speeds on low and high mode and report back.

Just a few moments ago, after finding a pdf parts list for Goodman furnaces, I finally learned that the HE Goodman GMV 2-stage furnaces do indeed have ECM blower motors, as well as a 2-speed inducer motor. Yikes! (But at least I now know that there are non-ECM inducer motors that are also 2-speed.)

But previous to that revelation I did search for "ECM troubleshooting" and found some very informative Youtube videos as well as the following older thread from this very site:
http://www.doityourself.com/forum/ai...ble-motor.html

If the ECM motors of today haven't changed much over the past few years, these resources make me feel that I might very well be able to repair what is apparently the most common problem wth ECM motors -- that thermistor on the circuit board in the "end-cap" controller.

From what I've read and seen so far, I guess the actual motor part of the motor/end-cap assembly is very reliable and it looks to me like the standard-looking bearings at each end of the rotor's shaft would be a snap to replace, IF one could find a source for them. I think it's a fairly safe bet that they are a standard size that one could buy in any place that sells bearings, such as BC Bearing, etc.

So, for the moment at least, I am keeping a open mind when it comes to ECM motors. Again, I'll see what dealers have to say about fan speed in low and high modes of their 2-stage furnaces.
 

Last edited by Darwin's Child; 02-15-14 at 02:21 PM.
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Old 02-15-14, 03:01 PM
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Good read & virtually nothing has changed other than on some (most if not all) motors you can buy just the control side or the motor side. Still, service people are stuck not having any way to program the control side. Very few distributors even have programers & they can only program for the equipment brand they sell. I had to wait over a month for a warranty motor.
No service person I know is going to stick his neck out far enough for Mr. Lawyer to chop his head off when his repair of something he's really not qualified to do goes bad & causes a fire. That's why I discourage the use of ECMs.
 
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Old 02-16-14, 12:04 AM
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I have a Lennox G60DFV two-stage, variable speed (ECM) furnace that was installed in March of 2006 and I have had absolutely no trouble whatsoever with the ECM motor. This also includes a period of time (ending a couple of days ago) when the return air filter was plugged almost completely.

It is true that the original equipment ECM motor is horribly expensive IF you have to have it replaced but I suspect that those replacements are a small, probably a very small, percentage of the number installed. Yes, it sucks for the person having to replace one but the odds are probably well in your favor that you will have no problems, especially if the furnace installer checks the duct pressures as they are supposed to, although my installers did not check anything but merely told me, "Yeah, it sounds okay to me."

Personally, with the increased comfort level from a two-stage AND variable speed motor I would not have anything else.
 
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Old 02-16-14, 11:13 AM
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Grady, I understand completely about the legal issues for the person doing the repair. I'm not so much worried about the motor being replaced during the warranty period, although if the labor is not included and the labor charge is more than whatever the going rate is for say 1 hour, I am worried. (Someone reported in the thread referenced above that the miscellaneous charges were going to add up to around $500, if my memory is right.) But I am indeed worried about being without heat for however long it takes to get a replacement when it's -30C, or even F, outside. One month to get a part is shocking, especially if it's a popular brand. But, again, we will still have the Rinnai and, if necessary, small electric heaters for the basement, so it wouldn't be a disaster.

Furd, thanks for reporting your experience with your ECM furnace. Again, our similarly-aged Rinnai has an ECM with modulating gas valve and the thing has performed flawlessly so far and keeps a very steady temperature, which I have to admit is very nice. But 6 or 7 years old is not 10 or 15 or 20 or 30 years old.

I understand that the days of the Maytag repairman getting paid to sit around all day twiddling his thumbs are over. As far as I can tell, washing machines and refrigerators and water heaters and furnaces that have a 35 - 50-year life expectancy are no longer being built.

Are these ECM motors and modulating valves and IFCs and pressure/temperature sensors going to age gracefully, or are they of the same "quality" as those POS ECM termistors and going to become an economic disaster for their owners (and the geese that lay golden eggs for their makers and maintainers)? That is THE question that at least some early adopters have already answered and, for many, the answer has been "disaster" in either parts or labor costs, or in the UNavailablity of parts directly to the DIY owner of the furance.

So, being a decicated DIYr who absoutely worships built-in, trouble-free, long-life reliability, the day our Lennox G furnaces are finally pried from our cold, dead hands and we then have the "freedom" to choose between paying for a new furnace or freezing to death, I'm going to be asking myself the same question Harry Callahan recommened to that teflon-coated killer in "Dirty Harry" -- "Do I feel lucky?"

(The whole issue of how well and, therefore, how often a simple or complex object should be built, is a very serious one that is way OT. But I will state the obvious. If, for any reason, an economic system pregressively evolves to rely on increasingly unreliable, throwaway crap being built over and over again, that economic system is going to fail catastrophically.)

I take it that what is of concern is an ECM blower trying to maintain a rate of output flow against excessive resistance to that flow, or, for lack of a better term, "backpressure", correct? In our case, I don't think that that is going to be a problem by a long-shot. If anything, it'll be the opposite -- as if the furnace were just sitting there running without any ductwork attached. Although the return temp will not be as cold as say outside air, it might be cooler than required to maintain an adequate temperature-rise spec. In that case, I suppose an appropriately-sized "short circuit" loop could be installed, or, as Grady suggested, restricting return airflow a bit. In the latter case, differential pressure between intake and outflow may not be correct. In the short-circuit, the total BTU output would be perhaps somewhat reduced. But I am not experienced enough to be certain of the ulimate affect of either option, and in this case I think experience is the best teacher.

Just to ramble (have you guessed that I'm retired?), if you compare the construction of a typical, non-ECM motor to that of an ECM motor, other than the permanent magnets and different angles of the stator windings, the major difference is the inverter/control module. I really don't think that the former would add much, if anything, to the cost of the motor part of the assembly. (I have personally rewound by hand the split-phase stator in a 1/3 hp motor and, believe me, it is a tedious chore, but the wire was dirt cheap.)

So, how much do you think it costs to acquire the parts and assemble that bone-simple end-cap circuit-board in a mass-assembly situation? If the total, out-the-door-of-the-factory price of that module by itself is more than $30, I'd be very ed.

And if the price of the motor part of the assembly is any more than just about any other common single-phase motor with start and run windings of equal horsepower, I'd be very surprised.

So exactly why are these ECM motors so expensive? In short (pun and irony intended), the cost of these motors to the end-user, and probably as well to the dealer/installer, is almost certainly wildly inflated because of the market-control or mandatory-pricing policies/contracts being enforced by the big-name furnace manufacturers -- the ones feeding and fleecing, remote-control, from the top of the food chain. I have almost no doubt that this situation cannot be sustained. Even though there might be only a few manufacturers of these components worldwide, over time (if a "free market" actually exists anymore) supply cracks will form and widen and far less expensive ECM motors will become available -- perhaps motors that even have immortal thermistors.
 
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Old 02-18-14, 01:46 AM
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As far as I can tell, washing machines and refrigerators and water heaters and furnaces that have a 35 - 50-year life expectancy are no longer being built.
I'm also retired so I think I can speak with some authority. Those items were never built with a life expectancy of 35 + years. The FACT that many of them made that lifespan was due more to preventative maintenance and sheer dumb luck than anything. Back in my youth the household refrigerator was expected to last about 20 years and the majority of them did. Now during that 20 years they might have required a shot of refrigerant or the replacement of a starting relay or capacitor but that was pretty much it. I remember our old rounded corner refrigerator having the starting relay changed and I think the entire refrigerator was still working when we got a new 18 cubic foot model. Washing machines would last about 10 to 14 years, which maybe wasn't too bad for a family of five. From my earliest memories to the time my mother died she had three refrigerators, the last for only a few months. That one in between got a couple of shots of Freon over the years to keep it going but it finally bit the dust after about 25 years.

The furnace that came with my house was about 18 years old when the burners needed replacement. Everything else about it was fine but I couldn't see dropping close to $600. in it and still having an 18 year old furnace when I could have bought a new equivalent for $750. I splurged and bought one of higher efficiency and much improved design for about $2800 installed or maybe twice the installed cost of an OEM replacement but I couldn't be happier because I didn't have to do the work other than writing the check.

I keep getting notes with my electric bill to buy a new "energy efficient" refrigerator but with the cost of the model I might like to have being in excess of $2000. I can afford to be a little less efficient. As it is my operating cost of the current refrigerator is less than five bucks a month according to my Kill-A-Watt meter. I'll die long before I could amortize the cost of a new refrigerator from energy savings.

I don't know how long the ECM motors will last. From what I read the two things that are most stressful to them are lack of cooling air, generally caused by plugged return air filters, and power surges. You can buy add-on supplemental surge suppressors (Technical Service Tools: ECM Motor Protector) or use a whole house surge suppressor. I think that pre-made suppressor is outrageously expensive but then again, the person that determined what leads to connect, got the suppressor and the Molex plugs and connect it all up does deserve to be compensated as well.


The whole issue of how well and, therefore, how often a simple or complex object should be built, is a very serious one that is way OT. But I will state the obvious. If, for any reason, an economic system pregressively evolves to rely on increasingly unreliable, throwaway crap being built over and over again, that economic system is going to fail catastrophically.
I completely agree. I'm only glad that I will be dead when it happens. I have never been in favor of board-level integration to the degree we now see. When I was working I did a lot of instrumentation/automation projects but I always preferred to use discrete components over fully integrated solutions both in the interest of easier troubleshooting and in ease of repair if it became necessary.

So exactly why are these ECM motors so expensive?
I suspect it is as you stated, the manufacturer of the motor (GE) has wildly inflated the price, perhaps to try to recoup the development costs in a very short time frame. As far as I know GE still holds all the patent rights to this design and I think they are milking it for all it's worth until the patent runs out. Obviously the ECM motor is more expensive to build than a multi-speed split-phase or PSC motor but it isn't ten time the cost, not by a long shot. But I'm pretty sure it isn't the furnace manufacturers that are driving up the cost as they simply buy from the motor manufacturer to meet the needs of the furnace. In some cases it could be a shared responsibility in that too often the furnace manufacturer will specify a special mount or special speed or something instead of a generic motor.
 
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Old 02-18-14, 12:41 PM
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Furd, our experience with appliances is a bit different than yours, but maybe we are luckier.

Last year a Panasonic microwave oven that my wife bought in about 1983 failed. I disassembled the thing and found the faulty part that needed replacing, but I could not find a new part, so that was that. We bought a new Panasonic that I have serious doubt will last even 5 years.

We moved to our present home about 14 years ago. Before moving from our previous residence, which was quite some distance from our new one, my wife gave away a top-loading Maytag washing machine that she had purchased in the early 1970s. As we looked at our new home before purchasing it, the then owner told as that the washer and dryer would go with the house, but that the original owners of the house (after it was built in 1977) had purchased them and to keep that in mind. My wife was fascinated with the new front-load Neptune machines, so about 4 years ago we gave away a perfectly running, 29-year-old, top-load washer and dryer and replaced them with a Neptune set whose washer has been un utter financial nighmare. Last year I disassembled the thing and replaced a bad drum seal and bearing. When anything whatsoever goes wrong with the POS in the future, we'll replace it with the cheapest big-name, no-electronic-gizmo-anything, top-load machine on the market. (And maybe that would be a good strategy for the furnace, but I must admit that I'm attracted to variable speed and modulation, as long as I can DIY fix them.)

Here's a photo of the label on our hot water heater:


The previous owner told us the water heater was original to the house and the label indicates a date of manufacture of March, 1978, so he was probably right. As far as I can tell, the thing still operates perfectly.

The previous owner told us that the two furnaces were orginal to the house. I believed him. They're still operating and have required minimal, inexpensive maintenance.

Our house was built as part of a 50-house development by one builder. All homes were finished at about the same time. The builder put the same furnaces and water heaters in every house. As I said previously, our neighbor had his two furnaces and water heater replaced three years ago and he told me that there was nothing wrong with any of them. The same is true of the neighbor on the other side of us, only hers were replaced a bit earlier. Last year her "new" water heater failed and needed a $400 service call and part replacement. She was choked. She also told me that her new HE furnace has had to have several service calls which to this point have been under warranty, but she's dreading the future.

Three years ago we had the refrigerator replaced that was original to the home. All it needed was a part that was no longer availble. We bought a new refrigerator that even the sales person admitted would likely have to be replaced in 10 years.

Automobiles of today are intentionally built and priced and warranted so that the owners will be taking their new vehicles to the dealership many times for those mandatory do-this-or-void-the-warranty items that cost the owner thousands. The dealerships need the work and the manufacturers give them exactly what they need and we pay for it on both ends.

I've already mentioned are dauhter and son-in-law's Lennox's frequent IFC board failures. I, too, have thought that a component-styled control system would be much easier on the wallet for the consumer. Why not just replace the actual component that has failed rather than a whole IFC? I've even been thinking of creating a "bread board" replica of whatever furnace's IFC we end up buying, so that whatever part fails can be easily and inexpensively replaced.

The list goes on and on. Most young people don't even know that there was a time when things like these were built to last -- whether the manufacturers realized what they were doing or not.
 
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