sizing question: PEG-35 / PEG-40

Bennett

Hello,



I have two quotes in hand for replacing a leaking Burnham 7. One is for a Weill-Mclain PEG-35 and one is for a PEG-40. The guy who gave me the PEG-35 quote did a ton of work, measuring all the radiators, taking copious notes. The guy who gave me the PEG-40 quote said "how many radiators do you have" and that's it, so it's clear that the PEG-40 is a little oversized.



However the quote for the PEG-40 is several thousand dollars less then the PEG-35 quote and the company is fairly well regarded.



Keeping in mind that I also intend to run an indirect hot water system off of the boiler, how badly oversized is the PEG-40? Will it be so bad it short cycles, etc etc or is there just a little room in it?

nicholas bonham-carter

Not apples to apples

There is more difference here between the two estimates than the boilers.

A bad job of piping with a bigger boiler could still be less cost, than a smaller boiler with correct piping.

Now have the lower one back and show him your calculations for the edr of the radiator total, and the downloaded boiler manual, and make sure on the contract that he will make the correct boiler selection, and the right piping.--NBC

Hap_Hazzard

How do these ratings compare to your existing boiler?

If I can believe what I'm reading, both boilers are a lot smaller (i.e. lower capacity) than the one you're replacing. Unless you've had a lot of radiators removed, or your old boiler was way oversized, or I'm looking at the wrong ratings or something, these are both too small.



Bearing in mind what Charlie Garrity has been seeing--undersized boilers based on heat-loss calculations instead of balancing connected load--you might want to do your own radiator survey and see what you come up with.

Bennett

oil to gas

Just to add -- the Burnham is an oil burner, this is a natural gas conversion.

John Mills_5

Corners

If he cut corners sizing the sucker, what corners is he going to cut on the install to reduce his labor to come in cheaper? 

ALIGA

Save a few hundreds

Ny asking the guy to give u a Williamson, which is a weil mclain with a green jacket

JStar

Steam

Sounds like one of my old bosses. He would count the radiators and multiply by 40 to get the boiler output. I secretly followed up on every job and found every single boiler oversized by no less than 30%. Some as much as 200%.



So, you either pay for the expensive job now, or you pay to use more fuel later. Ask the contractors exactly why they chose the size of the boiler.