New Boiler installation, Baseboard in one zone can't keep up with cold.


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Old 01-24-14, 10:34 AM
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New Boiler installation, Baseboard in one zone can't keep up with cold.

I had an oversized (119,000 BTU out) oil boiler replaced with an energy star induced draft gas boiler October 2012 by Home Depot. It is a Weil Mclain CGI-4 with the dual speed burner (66,000 BTU out). I have two zones with 2 ciculators with check valves. Being a cape cod, the second floor zone is smaller and has low ceilings. That floor is mostly storage, and is set back to 55 degrees. The main floor zone is all one loop. They replaced my old circulators with Grundfos UPS 15-58 FRC with three speeds.

The new boiler had a defective control board the first season, so it could not reliably produce more than 140 degrees. By the time the installers got the correct board installed, it was March, and the heating season was mostly over.

Now comes December 2013, and we get some real cold. I have a setback thermostat, and I found that the new boiler was heating unevenly, and had a long recovery time.

- If the overnight low temperature was between 35F and 45F, the first 3 rooms on the loop would get a little too warm when morning ended the setback, and the last three rooms would not quite make it to the morning set temperature.

- If the overnight low temperature was bbetween 25F and 35F, the first 3 rooms on the loop would get way too warm when the setback ended at 5 AM, and the last three rooms would not make it to the morning set temperature for many hours. I changed the setback from 64F to 67F, which helped the problem.

- lately, we have been getting overnight temperatures in the single digits to low teens. The temperature in the morning where the thermostat falls to 64 degrees, when the setback is 67. I watched the boiler, and it is running on an 8 minute cycle, where it reaches the high limit in about 4 minutes (first two minutes are at the lower gas setting). It took 5 hours for the heat to recover to 69 degrees, by which time it was 24 degrees outside.

I have contacted Home Depot, and the Contractor, and they are both telling me they can't do anything because it is more than one year. I am unemployed, and I can't afford the $98 charge they want for a burner cleaning, in the hope that they solve the problem while they are at it. The technician I spoke to has stopped returning my calls.

To summarize:
My old system was able to keep up with minus 15 degree temperatures back in 1994. It could recover from a 10 degree setback when I came back from a weekend away, within in a few hours.

1) The new boiler, with a working control board is able produce enough BTUs to reach its limit capacity, even if set to 205F. If the boiler was too small, it would run non-stop, and never hit the limit.

2) The old Baseboard was not replaced, and was able to radiate a lot more heat with the old boiler and Circulator, even when it was minus 15 outside for a week.

3) I never hear expansion noise (I did with the old boiler), and the circulator seems to run almost constantly.

4) I have never heard any of the tell-tale gurgles of trapped air. Still, I have bled every radiator twice.

5) I put a 4 foot section of slant fin under my bathtub 20 years ago. The bathtub used to get nice and warm. With the new boiler system, you can barely feel the warmth. The bathroom is the second room on the loop.

6) Both zones have all copper / aluminum fin baseboard in series (with a small convector in the bathroom).

My theory is that the Grufos Circulator is not big enough, or there is a blockage somewhere. I have 175 feet of 3/4 pipe, mostly Copper, but 20 feet of which is cast iron. Add 100 "effective feet" for the 50 or so elbows, and you get 275 feet. The calculator I used gives this as about 17 feet of head. That figure does not account for any resistance inside the high efficiency boiler itself.


Looking at the pump curve for the pump at High speed for the circulator, That puts in at about 5 Gallons per minute. That should be adequate, so I suspect a blockage, or an error in my calculations.

QUESTION: how do I measure the actual flow rate of the operating Circulator?

Possible solutions:
1) I can't afford a bigger pump, but I found a Taco 007 series pump on Craigslist for $25. I could put the Craigslist pump in series or in Parallel. This would give me more "head" if it is in series, or more flow if in parallel. I would like to know which I should try.

2) I could break up the first floor zone into two or three parallel loops. This would allow me to put in balancing valves. I have wanted to do this for years, since the kitchen is the last on the loop, and it does not have enough baseboad to keep it warm. I have a fan on a thermostat blowing on it (when the pipe is above 100F, the fan blows), which used to be enough to keep the kitchen warm.

The problem with this solution is that I would need 35 feet of 1 inch copper pipe, plus fittings, which would cost $150+ (as much as a used 1/12 HP circulator).
 

Last edited by gromittoo; 01-24-14 at 12:48 PM.
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Old 01-24-14, 10:41 AM
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When they replaced the boiler, did they reverse the flow of water thru the system?
 
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Old 01-24-14, 12:21 PM
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The water flows in the same direction through the loop, but there did change the location of the circulators. In the old installation, they were installed in the return pipes; in the new install, they are in the feeder pipes.

Also, it really annoyed me when they were finished, the head installer was going over the valves that were installed. He told me that Circulator 1 feed the first floor, and ciruclator 2 fed the second floor. I know where the pipes go, and knew he had them backwards, but he insisted. Turns out they had the thermostats wired backwards too. I don't think the TACO 2 zone controller cares which zone is zone 1 vs 2.
 
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Old 01-24-14, 12:38 PM
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re-reading my original post, I forgot to mention that I tested the upstairs zone.

The test was to increase the thermostat by 10 degrees when it was 24 degrees outside. I could hear all the usual pipe expansion noise, and the second floor temperature increased by 5 degrees in about 25 minutes. The boiler ran almost continually for the first 12 minutes, but did reach limit temperature. I am satisfied that the boiler works with the second floor, but there is only about 150 feet of "effective length" of 3/4 copper pipe on that zone.
 
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Old 01-24-14, 12:39 PM
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Are the 15-58's running on high now?
 
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Old 01-24-14, 12:52 PM
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mostly Copper, but 20 feet of which is cast iron
Cast iron? You mean black steel, right?

I think the head loss of your system is probably less than your estimate, my guess would be around 12 feet of head.

The 15-58 should be more than able to pump that system PRESUMING that it's a 'series loop', do you know if it is? Are you sure it's not a 'Monflo' (tm) system?

You will be wasting effort and money replacing the 15-58 with a used 007.

Here are my questions:

How many feet of ELEMENT, not the pipe itself, but the FIN-TUBE ELEMENT, is installed on the loop?

What is the temperature of the water going INTO the loop, and the temperature of the water coming OUT OF the loop?
 
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Old 01-24-14, 03:11 PM
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1) The house was built in 1922. The non-copper pipe is whatever was used with the original cast iron radiators and might be painted black rather than silver.

2) You may be right about the Hl. I redid the calculation using 5 Gallons per minute, rather than 6, and I get 13.5 feet (see details below)

3) Both circulators have always pushed (or pulled) a series loop. I have never heard of "monflo" so I will assume it does not apply. I like the idea of changing the first floor to a series parallel loop, so I can use balancing valves. That would be really expensive because it requires running a lot of 1 inch copper.

4) I was not suggesting replacing the Grundfos with the TACO 007. I was reading where you can double up pumps, and get more flow (two pumps in parallel) or more head (two pumps in series). Both the TACO 007 and the Grundfos have 1/25 HP motors. I have not been able to find even a used circulator that has 1/12 HP motor for under $200. Doubling up the pumps on the same zone might be a cost effective way to increase the flow.

5) Feet of Element, in flow order:
BR#2: 7 feet of Slant Fin 30
Bath: A small convector with 3 parallel tubes, and aluminum fins, fin area ~1 foot bu 6 inch.
Under bathtub: 4 feet of bare Slant Fin 30 element
BR #1: 20 feet of Slant Fin 30
LivRm: 22 feet of unknown brand fin
DinRm: 11 feet of unknown brand fin
Kitchn: 7 feet of unknown brand fin
Note: thermostat in Dining room.

Total active baseboard: 71 feet, not counting the convector in the bathroom.

6) Temperature coming out of the boiler is whatever I set it at. Currently the limit is set to 200, so the boiler cycles between 180 and 200 I have not been able to figure out a way to measure the return temperature. I have a cheap IR thermometer from Harbor Freight, but I can't get consistent measurements. Given that:
- the return pipe feels as hot to the touch as the pipe going into the loop (too hot to touch)
- the boiler reaches temperature quickly, and only runs at most 33% of the time (22,000 BTU) while the circulator never shuts off
- The radiators just don't feel like they are giving off as much heat as I know they are capable of.
Given the above facts, I would say that the temperature drop between the input and output is not very much.

Note: if the upstairs zone calls for heat, the temperature difference is quite large, indicating a lot of heat has been transferred.

Is it possible that I have a bad Grundfos Circulator on the first floor zone? Could the installers accidentally left something inside the pipes, when the sweated the new part on? Could the installers have messed up (melted?) the removable check valve? If I move the speed switch, I do hear the motor speed change, but the pipes don't make any different sound. I always leave the speed set to high.


My calculations:
175 linear feet of 3/4 inch copper pipe, add 2 feet for each of the 50 elbows... total 275 feet.

From "TACO Radiant made easy application guide / Selecting circulators":

Step 4: Establish the Head Loss

Hl = k * c * L * f **1.75

Hl = Head Loss (in feet)
k = Factor based on tube size (0.00295 for 3/4" copper)
c = Correction factor for fluid type ( .993 for 180F plain water)
L = "equivalent Length" ( 275 feet calculated above)
f**1.75 = Flow rate raised to the 1.75 power ( 16.7 for flow rate of 5 GPM)

Multiplying all those together, I get 13.5 feet. I think I used 6 GPM in my original Calculation, which would give a larger Head Loss result. My guess based on the poor performance and the total lack of any expansion clanking, the flow rate is much lower.
 
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Old 01-24-14, 03:41 PM
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The non-copper pipe is whatever was used with the original cast iron radiators
STEEL, not cast iron.

I have never heard of "monflo" so I will assume it does not apply
If you've never heard of it, then how can you 'assume' anything? You've got nothing to base your assumptions on!

Can you follow the piping arrangement going to the radiators? Or perhaps take some pictures and show us how they are connected?

Is there ONE pipe that runs around the building and each radiator connected to that single pipe with TEE fittings? If so examine those fittings carefully to see if there are any 'arrows' on them indicating flow. This would be a 'monoflo' system.

Does one pipe leave the boiler, go into one radiator, out of that radiator and into the next, and so on all the way around the loop? This would be a series system.

Are there TWO PIPES going around with each radiator connected between them? This would be either a 'direct' or 'reverse' return system.

We need to know how the system is piped. Each type of system has different properties we need to consider in order to come to some conclusion.

Both circulators have always pushed (or pulled) a series loop.
It seems that you are reasonable sure that they are series loops, but I need you to confirm this by examining the system. Can't help unless I'M sure!

The fact that they changed the location of the pumps is a GOOD THING, it is a BETTER way to pump a heating system for a number of reasons which I'm not going into at this time.

Doubling up the pumps on the same zone might be a cost effective way to increase the flow.
It would increase the flow, but you are jumping to conclusions that you know what's wrong, and frankly, I don't think you do. No offense intended... just saying... so you don't do work and spend money that you don't need to.

Total active baseboard: 71 feet, not counting the convector in the bathroom.
That's not too bad... really the so-called 'design limit' for baseboard on a 3/4" loop should be around 65' or so... but 71 isn't bad...

I would count that convector as perhaps 10 feet, probably a 5K BTUH convector which is about equivalent to 10' of fin'tube.

So, let's say you've got the equivalent of 80' of fin-tube. That's a bit more than 40K BTUH of heat emitter output... maybe 45K ... and to get ALL those radiators hot, you shouldn't have to pump more than 4.5 GPM. I do not believe that 15-58 has any trouble producing that flow in that system. I'm going to check a few more things to be sure, but for now I don't think so.


more......................
 
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Old 01-24-14, 03:47 PM
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I have a cheap IR thermometer from Harbor Freight, but I can't get consistent measurements
There's this annoying thing about infra-red that screws up those thermometers... it's called emissivity and what this means is that different materials emit IR at different rates, so you get different readings.

Here's what you do:

BEST: Paint the section of pipe that you want to measure FLAT BLACK. This will level the playing field if you are only looking at ONE type of surface.

OK: Wrap one layer of black electrical tape tightly around the pipe you want to measure.

As long as you measure the temperature of the same material in all places, even if the readings aren't accurate to the single degree, at least the DIFFERENCE between them will be close enough to judge what's happening with the flow.

more..............................
 
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Old 01-24-14, 04:05 PM
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- the return pipe feels as hot to the touch as the pipe going into the loop (too hot to touch)
This clearly indicates that you have adequate flow in the system.

If you had a flow issue that was serious enough to cause the heat imbalances you say you are having, the return pipe would be MUCH COOLER than the supply pipe!

- The radiators just don't feel like they are giving off as much heat as I know they are capable of.
Perhaps not. When was the last time that the covers were removed and the dust and pet hair vacuumed out of the fins? Particularly the BOTTOM of the finned portions because this is where the dust accumulates.

Is the BOTTOM OPENING of all the baseboards free and clear of wall to wall carpeting that can obstruct the air flow through them?

How about large furnishings?

Are the pipes into and out of each baseboard AS HOT AS THE SUPPLY AND THE RETURN to the boiler? i.e. can't touch them?

Note: if the upstairs zone calls for heat, the temperature difference is quite large, indicating a lot of heat has been transferred.
I know that it would seem that way... but it could also mean that the flow is LESS in the upstairs loop.

Let's think about this for a minute or two and consider two examples:

If you have a pipe 100' long and pump 100° water through that pipe very slowly, would you expect that the water coming out was COOL? Yes, you would...

How about if you pump the water through FASTER... would the water coming out be HOTTER? YES, it would.

WHY? Because LESS water is traveling more SLOWLY and thus giving up it's BTUs on it's way through the pipe. And being that you are moving LESS WATER (and this is an important point to understand!) there are LESS BTUs being carried in that pipe to be given up!. The result is that the AVERAGE WATER TEMPERATURE inside that pipe is LESS THAN the average water temperature inside the pipe with a faster flow.

Given this fact, which pipe would emit more heat? THE ONE WITH THE FASTER FLOW because MORE OF THE WATER INSIDE THAT PIPE IS HOTTER than the one with the slower flow.

So, let's say that the water in the slow pipe goes in at 100 and comes out at 70, that's an AVERAGE water temperature inside that pipe of 85F

In the fast pipe water going in at 100 comes out at 85, that's an average water temperature inside that pipe of 92.5F ...

Which pipe is going to give up more heat? the FASTER PIPE is the correct answer.

I know that it seems 'counter-intuitive' and believe me, it took me years to 'get it' myself!

Heat transfer is all about 'DRIVING FORCE'. The driving force is the DIFFERENCE in temperature between the heated object and the surroundings. The greater this difference in temperature, the MORE HEAT that will be emitted from that heated object.

Make sense?

more...........................
 
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Old 01-24-14, 04:09 PM
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Is it possible that I have a bad Grundfos Circulator on the first floor zone? Could the installers accidentally left something inside the pipes, when the sweated the new part on? Could the installers have messed up (melted?) the removable check valve?
Based on the fact that the return water is almost as hot (can't touch the pipe) as the supply water, I am going to say NO to all of the questions above.

I am not going to draw any conclusions until I know exactly how the loop is piped, so please look that over, post some pictures, (let's see the boiler and surrounding piping also) and we'll go from there.

Please dig through my previous posts and be sure to answer all my questions. Can't help much if you don't.

Plan?
 
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Old 01-24-14, 04:23 PM
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1) It turns out that you meant "MonoFlo", Not Monflo. I found a good description of MonoFlo, and I don't have any special tees with venturi in them. They don't sell monoflo tees at the Home Despot, so I didn't use them. Also I replaced all of the bedroom radiators myself, and put a new section under the bathtub. There are no pipes in in the basement parallel with the radiation sections.

2) The doubling up of pumps was something I was asking for advice on. The contractor that installed the boiler removed the old circulators, and replaced them with the Grunfos. The circulator for the second floor was a huge Bell and Gossett, and the other I never looked at closely.

The fact that the lead installer was so so insistent about which circulator was connected to which floor (and I knew he was dead wrong), had me suspect that he installed an undersized Grundfos circulator. A $20 used Taco is not a big investment, if it would allow me to turn my thermostat back at night to save natural gas.

3) The news about the active baseboard should not be a surprise. I added 14 feet of that 80 feet. The master bedroom was not quite warm enough, so I added 10 feet. I wanted my bathtub to be warm, so I added 4 feet. Still, this 80 feet of fins worked OK in January of 94, when the temperature in Philadelphia stayed between minus 15 and zero for more than two weeks.

Since then, I have wanted to split the first floor into two zones, with simple balancing valves, controlled by one thermostat.

I have a simple idea for troubleshooting this problem. I feel comfortable shutting down the boiler, and swapping the two circulators. If the problem moves to the second floor, I know I have a bad circulator. If the problem remains, then I need to figure out where the blockage is.

While I have the boiler down, I should install a reliable thermometer in the return line. I would really like to install a flowmeter, but they are really expensive.
 
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Old 01-24-14, 04:45 PM
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Should I turn the Grundfos to low speed?
 
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Old 01-24-14, 05:03 PM
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Pictures......please. And scroll down to answer NJ's questions
 
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Old 01-24-14, 05:16 PM
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No, turning the pump down will decrease the heat output. Read my posts again. You're not getting it.

Read through my posts and please address my questions. Can't help any further if you don't.
 
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Old 01-24-14, 06:09 PM
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I wrote this, and then found it won't let me upload pictures. Error 503 Service unavailable. I'll try again after dinner.

I am confused as to what you are looking for. The loop is exactly the same with the old and new boiler, with the exception that the circulators are now on the boiler output, and they replaced the old fashioned overhead expansion tank above the boiler, with a new bladder type.

Coming out of the top of the boiler is a big pipe with the pressure / temperature gauge(see BoilerFront.jpg). Also note the TACO two zone controller mounted on the side.

The pipe now makes a bend towards the back, where it meets the new expansion tank, and the autofeed and a green air scoop (see boilerback.jpg).

From there, the pipe makes two bends, and the circulators come out vertically (see boilerside.jpg). Immediately above the Grundfos Circulators (internal Check Valves), is a new shutoff valve. From there, the two pipes feed the two zones.

In the upper right (boilerside.jpg), you can see the return pipe from the second floor, and a drain valve (red handle/knob). Behind the drain, is a ball shutoff. Both of these were installed by me 20 years ago.

In the middle left (boilerside.jpg), you can see the return pipe from the first floor, and a drain valve (blue handle/knob). It is hard to see, but there is a ball shutoff in front of the drain valve. Both of these were installed by me 20 years ago, but for some reason, the installers had to replace the drain valve during installation.

I installed these drains and valves to allow me to isolate the drain from the boiler, then "backflush" the loop using a garden hose, back out through the boiler drain. The valve was of good quality, and I was surprised it needed replacing.

If you look at Boilerleft.jpg, you will see where the return pipes come in.

Pictures:
BoilerFront: http://i43.photobucket.com/albums/e3...ps7176fc72.jpg
BoilerBack: http://i43.photobucket.com/albums/e3...ps8022c7d8.jpg
BoilerSide: http://i43.photobucket.com/albums/e3...psd17c54af.jpg
BoilerLeft: http://i43.photobucket.com/albums/e3...ps3353c4fe.jpg
 

Last edited by gromittoo; 01-24-14 at 07:01 PM.
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Old 01-24-14, 06:13 PM
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Set up a free account at Photo and image hosting, free photo galleries, photo editing and upload the pics there and provide a link to your PUBLIC album.
 
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Old 01-24-14, 06:45 PM
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That is going to take a while. Pictures will have to wait.

Anyway...
Perhaps not. When was the last time that the covers were removed and the dust and pet hair vacuumed out of the fins? Particularly the BOTTOM of the finned portions because this is where the dust accumulates.
The lack of heat is dramatic. I have not cleaned those fins for at least 15 years. The effectiveness of heat transfer does not suddenly get cut in half in the 14th year of neglect.

As for the questions about Monoflo... I never heard of it before today, and I would have noticed the trademark name on any parts of the system by now. I don't have Monoflo.

As for Steel vs. Cast Iron, it really doesn't matter.

I have a boiler connected to two plain vanilla baseboard loops. One loop for each floor. Loops mean no branches and no Venturi's and no Tees. Each loop has its own circulator, and allegedly, the circulators have built in check valves (but they could have been removed).

What questions have I not answered?

Oh.. is it possible that the circulator for the problematic zone is running backwards? I have been reading the temperature on the gauge on the boiler as the "output" but using my fingers to judge the return line.

I will try the black paint trick, so I can get accurate measurements of the temperatures.
 
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Old 01-24-14, 07:28 PM
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OK, I took the advice of using the IR thermometer. I found that if placed the thermometer directly in contact with the black metal fittings at the boiler input and output, I could get reproducible readings. While the boiler control board was saying 184, the output reading on my cheap IR thermometer hovered around 158 to 160. The return line hovered around 143 to 145. So we get a 15 degree drop. Since I don't know the actual GPM, I can't calculate the BTU's delivered.

I wish they made something like this as standard equipment:
Blue and White Flow Meter F 44750LH 12 F 44750LH 3 4" Fittings | eBay

That particular flowmeter is made of plastic, so it wouldn't hold up on a boiler, but the principle is simple enough, that they could be made as a standard part of a boiler.


Now I have to go around and spray black paint on strategic points
 
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Old 01-24-14, 08:44 PM
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That's a bit more than 40K BTUH of heat emitter output... maybe 45K ... and to get ALL those radiators hot, you shouldn't have to pump more than 4.5 GPM.
So we get a 15 degree drop. Since I don't know the actual GPM, I can't calculate the BTU's delivered.
Actually, you can ballpark it to a reasonable degree of accuracy by knowing the emitter capacity and the delta T.

Looking at these numbers it is very safe to say that you have around 5 GPM of flow in that loop, perhaps a bit more.

I have not cleaned those fins for at least 15 years. The effectiveness of heat transfer does not suddenly get cut in half in the 14th year of neglect.
My recommendation is to open them up and clean them out.

It DIDN'T happen overnight, it happened over 15 years and it is coming to light now because it hasn't been this cold in decades, and at this point there is not enough heat output from the baseboards possibly because of the dust buildup inside.

this 80 feet of fins worked OK in January of 94, when the temperature in Philadelphia stayed between minus 15 and zero for more than two weeks.
Twenty years ago, when the baseboards were probably cleaner. And now we are having frigid temps again, you are running a perfectly fine delta T on the loop which means that the flow in the loop is fine, yet you are not happy with the performance.

I am telling you that the problem is NOT the boiler, NOT the pumps. Everything checks out.

And, NO, I can see from the pics that the circs are NOT backwards...

Get all your ducks in a row... clean the baseboards and see what happens. You would be surprised at the extra heat that comes out of them.
 
  #21  
Old 01-25-14, 09:52 AM
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Below is a cycle that I observered, and wrote down a few days ago. This was during a period when it took 5 hours to recover from the overnight setback of 66 degrees, to reach 69 at the thermostat. The "temperature" listed below is the temperature displayed on the boiler controller.

Time Temp* Event
0:00 179 Boiler Low Limit, Inducer fan turns on.
0:30 177 Low speed Gas valve opened and was ignited.
2:30 182 High speed Gas valve opened and was ignited.
4:30 200 Limit reached, gas turned off, inducer fan continues to run
5:00 198 Inducer fan turned off, Circulator pump continues to run.
8:00 179 Low Limit reached, Cycle continues


Last night, I was seeing the same cycle of about 8 minutes. I started using the IR thermometer on the black metal at the inlet and outlet of the boiler. I made mental notes of the delta T I was seeing. What I saw is that the Delta T varies from zero to 20 degrees over this 8 minute cycle.

I noticed that it actually reached a delta of 20 degrees, just before the limit was reached. Once the limit was reached, the Delta T drops quickly. By the time the low limit is reached, the Delta T is maybe 5 degrees. During the 45 seconds of "pre-purge" and ignition, no heat is added. By the time the low speed gas is ignited, the delta T is zero. It stays zero through most of the two minutes low speed firing, but starts to climb very slowly. Once the high speed is allowed to kick in, the delta T starts to go up pretty quickly, until the delta T reaches 20.

With my old oil fired boiler, the boiler's large water tank was a huge reserve of heat. When the low limit was hit, the oil burner would start firing at full blast within 5 seconds. My guess is that the Delta T on that old boiler stayed pretty constant through the on / off cycles, and certainly never reached zero.

The boiler control board has a connection for an outdoor thermostat. I have been unable to find any literature about this specialized control board. I would hope that adding the outdoor thermostat would skip over the 120 second low speed gas firing, when it is below freezing outside.

I believe I have two issues:
1) To get the 85% efficiency to get the Energy Star rating, the Dual speed gas valve sacrifices the stability of the delta T. With such a small internal water jacket, this boiler has little reserve to work with, when compared to my old Columbia boiler.

2) I am over the design limit on the amount of radiation fins (80 effective feet). This was not noticeable with my old boiler, but with the new high efficiency boiler, it is a problem.

To help with problem 1, I need to research if the low speed gas firing can be disabled safely. I believe it can, because the delay is accomplished using a solid state replacement of an old fashioned "Time Delay Relay" (see photo, below the control board, next to transformer). If I can get information about connecting an outdoor thermostat, that would be a safer approach. There is a two pin connector labeled "OUTDOOR".

To help with problem 2, I need to split the 80 feet into 2 zones of about 40 feet. I wanted to do that anyway, but it requires 35 feet of 1 inch copper, plus a bunch of fittings and valves. 1 inch fittings are more than 3 times the price of 3/4 inch fittings, which makes no sense to me (they only contain 35% more copper).

As an unemployed engineer with no income, I can't afford the copper. I will just give up the ability to turn back my thermostat at night, or when I go away for a few days.

When I get to splitting the zones, my question is if I really need separate thermostats and controls. I am hoping I could run two parallel loops, and use balancing valves.

NOTE: The boiler control board is a new version as of August 2012, and has a model number 1135-615. Previous Weil-McLain CGi-4E boilers used a different board, Model 1107-2. Both boards are made by some small Canadian company. The W-M replacement part number for my board is 381-330-012 Production Number 511-330-002.

I have searched for a manual for this board, but I have not found one. I have no idea what the "economy adjust" knob does.

http://i43.photobucket.com/albums/e3...psa744eecd.jpg
 
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Old 01-25-14, 10:10 AM
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And with all due respect, you are 'over-thinking' this.

Your hubris is not allowing a pragmatic thought.

I say again, CLEAN THE BASEBOARDS.

Look at it this way; any dust accumulation inside the baseboards is as good as INSULATING them. How can the heat get OUT if they are INSULATED?

If you have HOT WATER going into the baseboard loop, and HOT WATER coming out of the baseboard loop, then the problem is NOT FLOW, it is NOT delta T, it is the simple fact that you can't get the heat out of the baseboards to heat the home.

There's HOT WATER IN THE PIPES.

If you aren't heating the home properly there is only ONE THING that can cause this:

The BTUs in the HOT WATER are not EXITING the water through the pipe, to the fins, and into the air.

Stop over-analyzing this and take care of the BASICS first!

You can't bring your car to the shop for a tune-up if you've got a flat tire!

Rome burned while Nero fiddled.
 
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Old 01-25-14, 10:57 AM
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OK it might help to clean the baseboards... but that is at most 10-20% of the problem. To say that I have never cleaned them in 15 years is an exaggeration. Even then, dust cannot entirely account for the poor performance I am actually seeing. Dust would not explain the fact that I used to hear expansion noises when the heat came on, but I don't hear any sound now.

Oh but the second floor zone does make a lot of noise when the heat comes on, and it is performing as well as it did with the old boiler. Those radiator strips are just lying on the floor, because I was replacing the plaster with drywall, and never got around to replacing the covers.

A few years ago, we had a season with extended 20 degree temperatures (and the old boiler). The radiator that is sealed in under my bathtub made the bathtub feel like a heating pad on the medium or high setting. This year (new boiler), the bathtub just barely gets warm, as if someone had been sitting on it a few minutes earlier. I don't know how much dust is on that radiator strip under the tub, since it is sealed in. I do know that any dust under there didn't just suddenly appear 18 years after it was installed, enough to make such an obvious difference in performance. To make such a difference, someone would have had to stuff pillows over the heat strip under the tub.

There are other examples... The convector in the bathroom is noticeably colder (like 50% less heat). I cleaned that Convector last summer when I redid the bathroom floor, and I put the cover back on it correctly. I have fan on the kitchen baseboard, that comes on when the pipe reaches 100 degrees. This fan would overcome any dust issue. The fan comes on about half the time, and it is not keeping the kitchen warm as well as it did a few years ago.

Strangely, the Master bedroom is now too warm, even after I closed the dampers. Those fins have not been cleaned for at least 10 years. This bedroom was never too warm before the new boiler. The Master bedroom is after the bathroom in the loop. I have not heard any air in the system, but I have bled the pipes several times anyway.
 
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Old 01-25-14, 12:16 PM
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I understand all that...

Here's my point:

Unless the data regarding pipe temperatures you have stated is incorrect, then there is no way that the system can't be performing as with the old boiler.

You stated that you have a 15° delta T from the hot boiler supply into the heating loop, to the 'cooler' return from the heating loop, right?

If this is the case, and you do not have a monoflo system (you stated that you are certain of that) then why would you not get as much heat out of the baseboards as you previously did?

If you've got HOT water in, and HOT water out, how can the baseboards NOT perform as they used to?

Either your temperature data is flawed, or you do have monoflo system and there is air blocking the flow in the branches.

There's no other explanation that I can see.

Look at the pumps and tell me if they have " INTERNAL FLOW CHECK " valves installed in them.
 
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Old 01-25-14, 12:28 PM
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He told me that Circulator 1 feed the first floor, and ciruclator 2 fed the second floor. I know where the pipes go, and knew he had them backwards, but he insisted. Turns out they had the thermostats wired backwards too. I don't think the TACO 2 zone controller cares which zone is zone 1 vs 2.
I know how engineers hate to be contradicted, or their expertise called into question... (believe me that I know, all too well!) but I have to revisit this statement so don't get all pizzed at my objective thinking.

Let's just play a 'what if' scenario.

WHAT IF you are wrong? How would the system act if the thermostats were controlling 'crossed zones'?

Just think about it... don't dismiss the thought...

An educated mind is able to entertain a thought without accepting it.
 
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Old 02-11-14, 02:55 PM
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Here is my Point:

NJ Trooper stated:
You stated that you have a 15° delta T from the hot boiler supply into the heating loop, to the 'cooler' return from the heating loop, right?

If this is the case, and you do not have a monoflo system (you stated that you are certain of that) then why would you not get as much heat out of the baseboards as you previously did?

If you've got HOT water in, and HOT water out, how can the baseboards NOT perform as they used to?


I have a very simple explanation why there could be less heat!


- A BTU is defined as the amount of energy it takes to raise one pound of water one degree Fahrenheit.
- A gallon of water is 8.33 Pounds.
- If the flow rate is 6 gallons per minute, and the delta-t is 15 degrees, then in one hour: 6 gpm * 60 Min/hr * 8.33 LBs/Gal * 15 degF Delta T = ~45,000 BTU delivered.
- If the flow rate is 3 gallons per minute, and the delta-t is 15 degrees, then in one hour: 3 gpm * 60 Min/hr * 8.33 Pounds * 15 degF Delta T = ~22,500 BTU delivered.

If my theory is correct, and the old circulator had a larger motor, and it could push the water twice as fast, then my observation that it feels like the baseboards are only putting out about half as much heat is valid. The remedy of putting a $20 TACO 007 circulator from Craigslist in parallel with the Grundfos to double the flow rate would work.

A better solution in the long run is to split the zone. However, the cost of copper is currently prohibiting that.

My current solution is I have added a small fan on the radiator in the dining room (where the thermostat is). The fan is turned on by a 100 degree close on rise switch. This increases the delivered heat in the room with the thermostat. It works if I keep the thermostat at a constant 69 Degrees.
 
  #27  
Old 02-11-14, 04:33 PM
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I understand what you line of thinking is... but:

You are going into the calculations with the word " IF " at the beginning of each of your cases, and this is a 'presumption' which isn't really a valid argument.

Let me do the same and give some reasons why there may be flaw in your logic...

IF you have a given amount of heat emitter with a given output rating, AND you halve the flow rate, THEN your delta T will increase.

It is NOT a linear change, your dt will not double, but it WILL increase.

In other words:

IF your OLD pump was in fact moving 6 GPM, AND you had a delta T of 15F with that pump, AND the new pump is moving 3 GPM, THEN you will no longer have a 15F dt.

The output of baseboard emitter does not change as drastically as one might think it would with drastically different flow rates.

This is the rating with 180F average water temperature in the pipe:

FLOW vs. BTUH / Lineal Foot
1 GPM 580
4 GPM 610

Stated in another perspective, that's about a 5% increase in heat output for a 400% increase of flow.

I believe that the difference is due to the fact that faster moving water is more turbulent with less laminar flow which results in more 'scrubbing' of the BTUs from the water to the pipe.

Consult the following PDF file for more:

http://www.slantfin.com/images/stori...neline30_r.pdf

So the fact remains that you've got HOT water going IN, and ALMOST as HOT water coming OUT, and your baseboards will output nearly the same amount of heat whether the flow is 3 GPM or 6 GPM (which by the way is too much flow for 3/4" pipe... I forget if that's what you have and too lazy to read back... forgive my laziness please!)

It's all about the temperature of the water inside the pipe and very little to do with the flow rate.

[Which by the way is the reason that attempting to 'balance' heat output from emitters by adjusting the flow through them is a pointless endeavor, and why boiler manufacturers have moved toward 'modulating' boilers and TEMPERATURE adjustment of the water. Temperature adjustment is a MUCH MUCH more linear function when considering BTUH output of a heat emitter, and MUCH easier to control.]
 

Last edited by NJT; 02-11-14 at 09:37 PM.
  #28  
Old 02-11-14, 04:41 PM
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I thought of another way to approach this...

Measure the temperature of the water entering the baseboard run.

Measure the temperature of the water exiting the run.

Calculate the average water temperature.

Using the chart in the PDF calculate the BTUH output of the baseboard run at that average temperature.
 
  #29  
Old 02-11-14, 08:58 PM
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A couple of things... that old boiler may have added a lot of heat directly to the house... especially while doing the Herculean task of recovering from a huge setback.

Perhaps that's the essence of the situation here? You took away a big heat source, and you also took away some recovery capacity for your setback. Maybe just start off with less set back and start recovery sooner?
 
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Old 02-12-14, 10:11 AM
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The remedy of putting a $20 TACO 007 circulator from Craigslist in parallel with the Grundfos to double the flow rate would work.
I also wanted to mention that it is probably not advisable to place dissimilar pumps in parallel.

If the pump curves are not identical (they won't be with different pumps) you could end up with an 'oscillation' between the two... not saying that you WILL, but you COULD, so using different pumps is to be avoided.
 
  #31  
Old 01-03-15, 02:04 PM
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SOLVED: The problem was the high effceincy boiler added a lot of head pressure.

OK it is almost a Year after I started this thread. Back in September of 2014, I started shopping for a bigger Circulation Pump on eBay. I found a larger pump I could afford. I used the "Ask a Seller a question" feature to see if his $84 1/20hp Taco pump would make enough difference when compared to my current 1/25hp Grundfos. Note that is a 20% increase in HP. He replied through eBay, and told me to call him.

The salesman at the other end immediately knew what my problem was. It certainly wasn't dust.

My old oil boiler had a huge tank, with very large water passages in the jacket. This means it could be ignored in the head pressure calculations. The new boiler is an energy star rated gas boiler with tiny passages inside. The new boiler definitely adds a significant amount of head pressure to the whole loop. He told me I needed a Grundfos 26-99FC or a Taco 0010 1FC. These are 1/6th HP (significantly larger) pumps, and they cost three times as much (about $270). For some reason, the price of pumps jump significantly when you go above 1/20 hp.

Well I found a 1/6 Horse Grundfos pump for $75 on Craigslist, that had never been installed. I installed it in the loop that was having problems. It only has one speed, and I now have the heat that I used to have.
 
  #32  
Old 01-03-15, 02:50 PM
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It certainly wasn't dust.
If in 15 years you never cleaned the baseboard out, it was (and probably still is if you haven't cleaned them yet) a strong contributing factor.

For some reason, the price of pumps jump significantly when you go above 1/20 hp.
Economics of manufacturing mostly. They don't sell that many of the bigger pumps because almost nobody uses them. Price goes WAY down when they can manufacture and sell millions of them.

and I now have the heat that I used to have.
Just wait until it's as cold as it was when you started the thread.

I still stand by my original statements.

IF you did in fact have a 15F Delta T from supply to return on that run of baseboard, the problem was NOT FLOW.

If the data you provided was FLAWED, and you did NOT have a 15F DT, then and only then could there be a problem with flow (or something else).

Like I said... wait until it's ZERO outside for weeks on end before you claim SOLVED. You've got to compare apples to apples and you're certainly not doing that.

You're going to believe what you want to believe though... that's the way (some) Engineers are. I know.
 
  #33  
Old 01-03-15, 05:22 PM
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You still don't get it...

I don't know how you can state that a 15 degree delta-T without a doubt there is an indication of adequate flow. You can have a 15 degree Delta-T, and have only 1/2 GPM flow rate, and you will get 1/4th the amount of heat delivered than with 15 degree Delta-T and 2 GPM. There is nothing magical about a 15 degree delta T to indicate an adequate flow rate.

Here is the facts as I presented them:
1) With the new boiler in the steady state, with call for heat on constantly, the 66,000 btu boiler was running 25 percent of the time. This means the boiler was only outputting 1/4th of 66,000 BTUs to the loop. That is a measly 16,500 BTU. When we lost power for three days last February my 25,000 BTU Kerosene heater could barely keep the first floor of our house in the 50's.

2) Somewhere in this thread, it was mentioned that I should be able to get more than 30,000 BTUs out of my 74 feet of finned baseboard. Only getting 16500 BTU suggests a blockage was introduced. This lack of performance reminded me of when I first rerouted the pipes 20 years ago, and I had not properly bled the air out of the system. However, 20 years ago, I could hear the gurgling. Last winter I purged and purged the loop many times.

3) My biggest complaint was the recovery time. With the old boiler, I could set my automatic thermostat back 8 degrees on a 24 degree night, and the heat would recover in the morning in about 60 -90 minutes. Last winter, I experienced a SIX HOUR recovery time under the same parameters. With a 4X bigger pump, we have experienced several 24 degree nights this winter, and the recovery time is back to normal.

4) Dust doesn't suddenly appear when a new boiler is installed. And it certainly does not magically disappear when a larger pump is installed. A few years ago, the slant fin radiation under my bathtub would keep it toasty warm. With the new boiler and 1/25HP pump, I could barely feel any warmth, ever. With the 1/6th HP pump, the bathtub is getting warm again. I installed that radiation in January of 1994. It is physically impossible to access that radiation to clean it from dust. Did the dust get scared and run away?


In conclusion: I really wish I had talked to someone who understood that a Energy Star boiler will have a rather large pressure drop across it. Older boilers have a negligible pressure drop across them. Any "rules of thumb" about 15 degrees might apply to older boilers, but I believe they need rethinking if there is a significant pressure difference between the inlet and outlet of the boiler.
 
  #34  
Old 01-03-15, 06:30 PM
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There is nothing magical about a 15 degree delta T to indicate an adequate flow rate.
No, you're right, PHYSICS is not MAGIC.

You sire are the one that doesn't 'get it' and I've got better things to do than discuss this any further. Your system according to you is 'fixed' and I'm closing this thread.

Good luck.
 
 

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