High efficiency boilers

Paul_28

I have about 120 feet of fined copper base board. I thought the WM Ultra boiler would be a good choice. Now, I find that Condensing boilers should not be used in with fined copper baseboard. Which manufactures boiler gives the highest efficiency with system?
Thanks Paul

Tony_8

not that they shouldn't

just that their capabilities are not maximized with bbd. Most of the season they should still condense as you typically won't hit design temp more than 5 % of the year. Used with outdoor reset, condensing boilers are hard to beat.

Robert O'Connor_3

with copper fin

you're only reseting down to about 140 degrees for fin tube air convection to work right and the heat loss for the room was probably calculated with 180 to 200 degree boiler water. So if you're not likely at the condensing return temp why bother with an expensive complex modulating condensing boiler. Just get a simpler high eff boiler like Dunkirk Quantum, Burnham Revolution, or a wall hung boiler if you need the space (WM, Burnham, Monitor, Baxi are a few manufacturers).

Floyd_5

check out the ....

"condensing boiler" thread.

Tom Meyer

Temperatures

It's all a matter of temperatures. Baseboard typically wants 180 deg F water running through it. With a delta T (temperature loss through the baseboard) of 20 deg F, that brings your return water back to the boiler at about 150 deg F. That's perfect for a non-condensing boiler. But for a condensing boiler to be worth its money, it has to condense. In other words, the lower the return water temperature, the better the condensing boiler likes it. According to my understanding, the optimum water temperature operating range for the Ultra is out at 110 deg F and return at 90 deg F.

Tom Meyer
Senior Designer/Trainer
Precision Hydronics Corp
www.precisionhydronics.com

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Tony_8

guess what

I can buy an Ultra 105 within $200 of a Quantum. The Quantum is a condenser also. Plus the Ultra has reset "out of the box". 140F supply should be about 120F return, that'll condense. Bbd will work at 140 or less, it just takes more of it. Besides, design temp water is for design temp days. Simply not necessary all the time.
I think the benefits of efficiency outweigh the low price of simplicity.

Boilerpro_3

The Quantum is not just a condensor , but recuperative

boiler. It continues to condense up to about 180F return. This makes it a better match for high temp systems. I checked mine a couple days ago and at about 140F supply, and 125 return, exhaust temp was only 116 and efficiency about 97.8 % (assuming I worked the numbers correctly).

Boilerpro

hydronicsmike

Why can't a Fin Tube Convector (Baseboard)

be reset any lower than 140°F? Although very little, it still puts out heat at 120 or even 100°F supply, doesn't it?

Paul_28

still confused

Should I spring for the extra cost of the condensing boiler or not???

Kal Row

ps the jury is still out on that thread

in light of some peoples good experiences with baseboard run at less then 140 supply, which would make the return water less than 120, defiantly in the condensing range

I am starting a new thread called "baseboards run at low
temps"

Unknown

here's the data

http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=14924&mc=24#Message90070

Mark Hunt

Go for it


I have MANY systems in the field attached to "high temperature" distribution.

Floyd said it already, your baseboards were designed(or should have been) to heat the house to70 degrees when the outdoor temp is at it's normal low. "Design day" around here is about -10, so when it hits -10 the baseboard will want to see 180 degree water. Anytime it is warmer than
-10, you can lower the water temp. so that the output of the baseboard more closely matches the heat loss of the home. You can do this with any boiler, but cast iron and steel boilers need to be protected from low temperature return water. Condensing boilers love low return temps.

Bring your heating system up to date and get the condensing boiler. You will save money on your fuel bill.

Hope this helps!

Mark H

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S Ebels

Baseboard on reset

I have a 7,000 sq ft building with 6 zones of BB, all running on full reset. Works great. The boiler will run along at 115-120* supply all day long when it's 25* and above. This is a cast iron boiler (Buderus 334 series with a 2107 control ensuring proper operation at these temps) The pump logic shuts down the pump while the burner fires at temps below 105*. Been in for 4 years now with no trace of condensation in the boiler. The families that live in this building tell me they have never lived in apartments as comfy as these are. WOuld have been a great app. for a condenser but at that time there were none out there in the budget range required by the job.

That being said, I see return temps in the 95-115* range a lot in the shoulder seasons of the year and rarely above 140 in the middle of the winter. The system would condense just fine if the boiler were capable of it.

Moral of the story:

1. Go for the condenser

2. Oversize your BB to enhance lower temp capabilities.

3. Run the system on full reset

4. Just do it, don't look back, just do it. You'll never be sorry you did it right but you'll always wonder "what if I had............." if you don't.

Paul_28

BBD length

I have 120 feet of BBD in two zones.

LEAD PIPE

I agree

Get the condensing. I have baseboard with the ultra. My gas usage was 40% lower in Feb., cold month. The rest have been 50% less. YOU WILL NOT REGRET THIS DECISION.

Paul_28

Pictures

Do you have pictures of the installatiion? I am interested to see how it is done, so I can correct my piping plan.

Paul_28

Installations

I wish I could see pictures of your installations. I need ideas for the piping.

Kal Row

here is one for an ultra

Kal Row

here is a diag i did for someone

Paul_28

Expansion Tank

Can the expansion tank assembly be placed in the Primary Loop???

cg_3

Big assumption design at 180 degrees

my house is 1966 ranch with baseboard. they basically filled a wall with baseboard plus new windows and insulation in attic. I run reset at 136*F at design temp of 5*F with no problems. serveral single digit days in a row this season with house at 72*F. So if you have an older home with improvements, you may be able to run at lower temps at design conditions and thus utilize condensing boiler. run load calcs or experiment and run at lower temps if this is your residence. With condensing bioler try to get by with the lowest temp don't just assume you need 180*F.

Kal Row

An expansion tank is designed

to take up the expansion of water in the system as it heats up, this expansion is everywhere at once so you can technically put it anywhere – now if you happen to have a flat plate heat exchanger that physically isolates one side from another – then you need an expansion tank on each side

now we usually put it going into the air separator – near the outlet of the boiler, where the water is hottest, to make that the point of the high pressure also – both those two things combine to push the most dissolved air out of the water

why would you not want to put it where it is in my diag?, the point where an expansion tank connects to, is known, as the Point-of-ZeroPressureChange, since you cant increase the static pressure at that point – so we usually pump away from that point to increase the pressure on the outlet side of the pump – which keeps air out of the system, rather than pumping to that point which would force the pump to make a drop pressure differntial in order to move the water along -

get dan's book "how come" on this site

My diag is an extension of what Weil-McLain put in the ULTRA manual and if you look at it – both pumps are effectively pumping away from the PZPC

Paul_28

Better fit

I think there will be more space in the primary loop to mount the air scoop and expansion tank. Is that good reasoning???

Kal Row

Air elimination

should be the main consideration, that’s why it’s connected to the air separator in the first place, after that, I need a diagram of what exactly you want to do