Inherited an oversized boiler - what do I do?

Mike Reavis_2

to having a system that runs well.

Hire a good contractor off of this site to calculate your needs to heat the connected radiation, and piping and fire the boiler to the number you arrive at. Insulate the pipes. Clean the boiler inside, and out, and treat the water. Replace any failed traps etc. Monitor your fresh water intake. Inspect your chimney. Install CO monitoring to protect your family (this recommendation is not meant as specific to your house, fuel used to heat it, or any other reason outside of you want to safeguard your family).

Mike

Tony P

Oversized boiler installation - What to do????

Seeking professional advice.

I have purchased a 3200 sq ft tudor home with a two pipe steam heating sytem the boiler of which was recently replaced. A Weil McLain Model 478 boiler rated at 400,000 BTUs was installed (replacing a coal conversion) with a Carlin burner rated at 2.5 - 5.5 gph(201 CRD-w)which caused the previous owner of the house two seasons of trouble due to short cycling and other problems until the contractor replaced the burner with a Carlin Model EZ-1 rated at .5-1.65 gpm which seemed to rectify the problem.

It seems to me (layman) that this is a case of inadequate heat loss calculations and oversized boiler installation. I am concerned about the longterm consequences of running the system as is against the mfg's specifications. One observation is the accumulation of black soot at the top of the three story chimney. Having recently acquired the house, the previous owner has stated that the system is finally performing as it should.

What would you reccommend I do as the current owner? Would this be considered unsafe, or atleast a faulty installation? Would this pass muster with the plumbing and building codes? What recourse might I have to get the system corrected if necessary?

Thanks in advance for your repsonse.
Tony P.
Hartford, CT

Ron Schroeder

I often feel there is no such thing as an oversized boiler, just over sized burners. ;-)

What nozzle is the EZ-1 using now? How long is the run time on each fire?

Is it still steam or has it been converted to hydronic?

What do you do for domestic hot water?

Ron

Ken_8

Welllll...

You do have a problem. To make the water content of the boiler actually steam requires a certain minimum amount of energy. Then too, the speed and amount of chilling condensate return water will add to the burner "load" as well.

This is why a heat loss is irrelevant with steam systems. The boiler doesn't know or care how the walls are constructed. It only cares about how much water's in the boiler that must be made to change from water to steam - and how much condensate (water) returning challenges the steaming process.

The bottom line is not the S.F. of the home or the R-value of the walls and ceiling(s), but rather how much radiation (and the rsulting condensate) impacts the boiler's ability to steam efficiently.

The rule of thumb seems to be an issue of time. If it takes over ½ hr. for a cool (ambient) boiler to make steam (get the riser pipe too hot to touch), the burner is undersized. If it takes less than 20 minutes to make it hot, it's oversized.

Of course this is only a rough guide, a few minutes one way or the other is not a big deal.

So, the size of the house and the insulation are moot. The amount of radiation connected to the boiler is all that counts!

FYI, the W/M 478 can handle 1250 S.F. of radiation (EDR)

Recommendations? Find a contractor by clicking on the very top of this site, "FIND A PROFESSIONAL" When someone answers the phone that has technical background, ask him if he knows how to install a "vaporstat." His answer should be a clue to the level of competence you probably need.

Let us know how you make out.

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