Condensing Vs. Non-condensing boilers questions..


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Old 12-13-06, 03:45 PM
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Arrow Condensing Vs. Non-condensing boilers questions..

Hi,
I am new to the forum and new to heating overall. I have been doing a lot of research while getting bids for a new boiler in my house.

We just bought the house, built in 1910, renovated in the 40's. Roughly 2500 sq ft, old windows, a bit drafty. Currently has a, get this, 290K btu boiler from the 40's, running fine, but obviously in need of replacement. Based on our convectors(not on heat loss) our IBR is calculated at around 95-100, depending on the person doing the calculation.

I have been looking at many different boilers, both condensing and non. I was going to have a Buderus condensing unit installed, but have been told by a couple of installers that it is not a great idea as a result of the acid produced by the condensing process which is the reason the ultra high efficiency boilers are warranteed for so little time in relation to cast Iron non-condensing ones.

I wanted to get some experienced advice on whether this is a problem, as well as other reasons to/not to get a particular kind of boiler.

Also, I got a quote today for a Pennco unit, and am wondering how these are, as there is very little info available on them.

The non-condensing units I am considering are:
Burnham revolution series

Crown Cabo series

Utica (forgot the series)

and some others, including the Pennco I was quoted today.

Any and all help, advice and comments are welcome and appreciated.
 
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Old 12-13-06, 06:23 PM
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Condensing or Not

I'm not a "latest is greatest" type. I don't think the condensing boilers have been in wide use long enough to develop a track record & without that track record, I tend to lean toward non-condensing types.
I've never installed a Crown Cabo but I like the sealed combustion. I have used a lot of Crown boilers & have an oil fired CT-3 in my own home. They are good equipment but so is the Burnham. BTW. Burnham owns Crown.
 
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Old 12-13-06, 09:26 PM
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Originally Posted by HeyNow!
Hi,
I am new to the forum and new to heating overall. I have been doing a lot of research while getting bids for a new boiler in my house.

We just bought the house, built in 1910, renovated in the 40's. Roughly 2500 sq ft, old windows, a bit drafty. Currently has a, get this, 290K btu boiler from the 40's, running fine, but obviously in need of replacement. Based on our convectors(not on heat loss) our IBR is calculated at around 95-100, depending on the person doing the calculation.

I have been looking at many different boilers, both condensing and non. I was going to have a Buderus condensing unit installed, but have been told by a couple of installers that it is not a great idea as a result of the acid produced by the condensing process which is the reason the ultra high efficiency boilers are warranteed for so little time in relation to cast Iron non-condensing ones.

I wanted to get some experienced advice on whether this is a problem, as well as other reasons to/not to get a particular kind of boiler.

Also, I got a quote today for a Pennco unit, and am wondering how these are, as there is very little info available on them.

The non-condensing units I am considering are:
Burnham revolution series

Crown Cabo series

Utica (forgot the series)

and some others, including the Pennco I was quoted today.

Any and all help, advice and comments are welcome and appreciated.
I'm assuming you are talking about gas fired boilers, as Buderus doesn't make a condensing oil fired boiler. I highly reccomend the Buderus wall hung condensing boiler. It comes with a lifetime warrantee on the aluminum block, is extremely low maintenance (you just have to clean out the condensate trap every couple years - a 15 minute job). A trained professional can do a complete tear down of the boiler in 15 minutes, and have it back together in 15 minutes. The only tool needed is a screwdriver! They achieve 97-99% efficiency, and vent with PVC. The combustion air is taken from outside (sealed combustion) and doesn't need room air so you can install it in a closet. It is fully modulating and utilizes a room sensor to help maintain the most comfort with constant circulation. The water temp is adjusted to maintain room temp. I have never heard of an issue with condensate's acidity, other than Oil fired boilers, and it is the sulfur in home heating oil that can cause problems. Typically, too many comtractors make up "problems" with boilers they don't install, or they believe all the heresay they encounter. It will cost more in the long run to put in a boiler that operates at 82% efficiency. I also reccomend Stainless Steel indirect water heaters (www.Heat-Flo.com), although Buderus makes a very good indirect water heater too. My feeling is, the right equipment installed properly will save you thousands of dollars in operating cost, and increase your property value.
 
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Old 12-14-06, 07:32 AM
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I suggest that a good way to go about this is:

1) do a real heat loss. Using the convectors (BTW, what kind are they, exactly? Radiators, cabinet convectors, cast iron baseboard, etc.?) can serve as a crude check on the heat loss, but among other things it assumes that the installed radiation was sized correctly to start with. Maybe it was, maybe it wasn't.

2) if you plan to upgrade the building envelope (I've been helping a friend with his 1830 farmhouse, so have some experience with older homes -- it's amazing what you can achieve applying some modern techniques to these classics, plus you might find some cool stuff like the "Grover Cleveland for President" button we found in a wall cavity...), then using the current heat loss as a base, revise the heat loss for what you ultimately want to achieve for the envelope (e.g., new windows, more and better insulation, sealing infiltration points, etc.). Improving the envelope reduces the heat loss and makes whatever boiler you have increasingly oversized (unless it's a mod/con, but that comes later).

3) The heat loss, either base or "future," will give you the required water temperature for the design day. You can also figure up what water temps will satisfy less than design day conditions (which will exist about 99% of the heating season). If you can meet the heat loss with supply temps roughly
 
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Old 12-16-06, 10:06 AM
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Hi, and thanks for the replies!

I am going to be gradually upgrading the place with new windows and blowing in some insulation, but it will be very gradual.

So what I've been told about the problems with stainless tanks and acid produced with condensation is bunk? I was told it was the actual tank, not just the vent that was the issue. It was told to me by someone that installed a Buderus oil fired in my parents house. He liked it for oil, but not for gas, and he is 5 hours away so he would not be the one installing in my home.

If that is the case, I may begin to look at that unit again, as I was really impressed with the features and efficiency.

I am really leaning towards the Burnham Rev. series if non-mod/con, but it is not a name that contractors here use, so I am getting outrageous quotes for it.

Does anyone have any input on the Pennco units? I know they are made by Dunkirk, but documentation is sparse at best.

One quote for a Pennco was about $4100, and the same guy wants $8400 for the Burnham. I happen to know that the Burnham is $3150 or so retail (rv-5) shipped, so I cannot see where his pricing comes from with all the labor/accessories being the same as the Pennco unit.

The delivery system in the house is cabinet convectors. They are Trane, in wall(partially). All the actual convector units in the cabinets are roughly 2" in hight, and either 5.5" deep with 3 spines or 7.5" deep with 4 spines, and all vary in length from 20" to 68".

Contractors around here don't seem to want to do an actual Heat loss calculation. I am getting pretty frustrated with the service out here, as most are getting upset when they realize I've done some homework on this purchase.
 
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Old 12-16-06, 10:32 AM
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Originally Posted by HeyNow!
So what I've been told about the problems with stainless tanks and acid produced with condensation is bunk? I was told it was the actual tank, not just the vent that was the issue. It was told to me by someone that installed a Buderus oil fired in my parents house. He liked it for oil, but not for gas, and he is 5 hours away so he would not be the one installing in my home.

Contractors around here don't seem to want to do an actual Heat loss calculation. I am getting pretty frustrated with the service out here, as most are getting upset when they realize I've done some homework on this purchase.
Bunk? maybe, but more likely a mis-understanding.

I think Monitor is the only condensing OIL fired unit I've seen. There are numerous GAS fired condensing boilers.

You definitely do NOT want to experience condensation in an oil fired unit. The acid produced will rot the boiler in no time flat.

The condensate from a gas fired unit is pretty much just water, and the stainless parts will last a long time.

Just make sure everyone you talk to is on the same page in the hymnal and you should get proper info / opinions.

Don't feel bad about the contractor situation. It's like that here (NJ) too. I know there are a few pros around here, and I'm probably stepping on some toes, but my experience has been that 90% of them have more ego than brains. Apologies to the pros that don't fit this profile, but the parade of ones that have been through my door in the past 20 years fits the description.

-
 
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Old 12-16-06, 12:28 PM
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Can we step back a minute?

Since you're looking at a Revolution, I assume the fuel type is gas.

You really need to do a heat loss to see whether it is worth getting a condensing or modulating/condensing boiler. If you can only satisfy the heat load with temps above about 140F supply a lot of the time, then the extra effort and cost of a condensing or a mod/con might not be worth it. (Chances are, however, a third or more of the heating season can be done with condensing temps <140F.)

In an hour or two you can do a good heat loss with the slantfin software http://www.slantfin.com/he2/ and be within about 10-15%. We can help with that.

Yes, you are being fed complete bunk about the condensate. All condensate regardless of fuel type is acidic (pH of about 2-3, IIRC). The treatment and disposal of the condensate is no big deal.

I hear you on contractors who don't like knowledgeable homeowners. One guy in my basement was going on about something that was so wrong I nearly tossed him out.

Keep searching for a good installer who works with the equipment you like and he's comfortable with.
 
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Old 12-16-06, 01:08 PM
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Wink

It's not so much the knowledge, but the responses I get when I ask for a detailed, or even not so detailed breakdown of the costs. Most have the attitude that their estimates are what they are and should never be questioned, even when one I recieved was trying to get 35% OVER RETAIL for the Buderus unit, when we all know he is getting it at close to wholesale or even below. He also wanted $430.00 for a Taco cast pump that retails for $110.

Don't get me wrong, I know every business(including mine) has to make money, but when the costs are given to me in the cotext of the installer saying the labor will be over 3K and the unit+ peripherals around 7K, I get a bit P.O'd because in my research I've looked at prices as well.

The rest will give a halfway decent price on a cheap Pennco unit(I assume they get them rather cheaply) but overprice anything else to try and steer me to their preferred moneymaker. I'm about to pull my hair out.

Anyway, sorry for the rant. 3 weeks of this crap is making me nuts.

To answer your questions, yes, it is a Gas unit. I'm sorry I forgot to put that in earlier.

Thanks for the link to that slantfin heat loss software. I will do that myself if the next guy out doesn't get it. I'm in Western NY, about 1.5 hours S/E of Buffalo, so the winters are a bit long. Even in comparison to CT where we moved from.

So, the condensate is not an issue? Well, as we have no basement and a really tiny utility space to put this into, combined with the fact that we need to get a new 200amp breaker box in there within code makes the mod/con wall hung units a bit more attractive. Is the installation cost of these units that much more than the non-condensing units? If it is the same or close, I think that a 1-2K difference would be doable, but no more than that.

Money will probably be the deciding factor(aside from heat loss) for that decision.
 
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Old 12-16-06, 02:51 PM
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Originally Posted by xiphias
All condensate regardless of fuel type is acidic (pH of about 2-3, IIRC). The treatment and disposal of the condensate is no big deal...
[thinking cap]
Hmmmm...
[/thinking cap]

I didn't think the condensate from gas combustion was that bad... I gess I need to hit the study desk again. What's in the gas that can combine with what to make acid ? I thought it was just H C and O ???
 
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Old 12-16-06, 04:08 PM
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Acid

The condensate is acidic, no doubt, but the treatment (if req'd) is no big deal. Around here, we don't have to treat it before discharging into the sewer. Most of the time it is just pumped out onto the ground.
 
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Old 12-16-06, 04:51 PM
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Maybe closer to 4 than 2. Carbonic acid, I believe, among other things. Other half is the chemist, not me....
 
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Old 12-17-06, 07:51 AM
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condensate

Remember...this has to be inspected. Call the builing inspector in your town to see if it must be treated before dumped. I had a friend the other day tell me he had to treat the condensate before dumping it per the inspector....Thats crazy in my opinion... I saw a wall hung unit for instant hot water on This Old House with no storage tank and unlimited supply. Thats especially important for those who like long hot showers or have tubs, or kids.
Scrap the obscure unit,. like my professor said, "Your heating unit is only as good as those who can service it, and it's availability of parts".
Burnham and Utica are great boilers. You might want to check out the Pensotti and the Biasi, both are low mass boilers and locally available. I'm not sure what they use as a gas set up, but I'm sure they have a matched set for them. Your real cost saving is the building envelope. Insulate to the max and seal all penetrations. Contact the local utility company to do a free accessment, and they will also help you finance or issue you a rebate......its free!
OH!!! I had one customer eat a hole through a cast iron (25year waranty) boiler, inside of one year. They didn't read the install instructions completely....Check the PH, they had well water and the PH was a bit acidic, he had to install a water softener because of the large amounts of lime I think it was.
 
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Old 12-17-06, 09:38 AM
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about money...

In re-reading about the proposals, I would look at this way. You are buying the whole package. Most importantly, the installer. His skills, experience, ability to provide quality service down the road, etc.

In that respect, I would look at the installer quality, the equipment quality, and the bottom line. I wouldn't care too much about how he marks up his equipment. Some guys mark it up and keep the labor down. Some don't mark the equipment and the labor is higher. I have a personal preference for not marking up the equipment, but whatever.

Also consider the $430 Taco. Maybe he's also including a set of nice webstone isolation flanges, some fittings, etc. in that?

Nobody who's running a quality company is going to be cheap. They have to put trucks on the road to show up at your door, insure the company, pay the employees (maybe even -- gasp -- provide them insurance and benefits), pay for training, stock parts, and the list goes on and on and on. They have a very real overhead and if they're any good they know what it is and what they've got to charge to cover it and then also make a profit.

I understand where you're coming from, but I think if you look at the good, reputable contractors, you need only pay attention to the installer quality, the equipment quality, and the total job cost.

It also sounds like you may not have found a good installer yet, if you're getting the runaround. Be patient. I keep my hair short so I can't get a good grip on it to rip it out of my head.

Iko Iko.
 
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Old 12-17-06, 10:04 AM
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Originally Posted by xiphias
Maybe closer to 4 than 2. Carbonic acid, I believe, among other things...
OK, I did my homework

H2O + CO2 = H2CO3 ...

but ph probably closer to 6 ... not much worse than rainwater.
 
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Old 12-17-06, 12:47 PM
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There's more to it than that. I've read it's around 3. Can't remember where, though.
 
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Old 12-22-06, 08:49 AM
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Call the Triangle-Tube rep for your area...

Ask the rep for the name of a couple of installers in your area. The Prestige 110 and a Smart indirect is a pretty safe bet for your application.

It's a wall hung condesning boiler with a pretty good design. It's self-cleaning (but still get it serviced annually) as is their tank in tank indirect design.

If you can go with a condensing boiler I would, because there is quite a bit extra savings coming from them that doesn't really show up in the AFUE numbers. You'd be drawing combustion air from outside rather than sucking moist air in through your walls and you won't be able to warm your hands up on a cold winter day by putting your hands over the chimney (warm air syphions up out of normal chimneys - whether the boiler is off or on).

If Grady were ever going to warm up to a high tech boiler, this would probably be the one. ;-)
 
 

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