Identifying boiler capacity

Waterbury Steam

I have an old Weil-McLain boiler that's probably been in the house for at least 20 years and I can't find any information on the model number or the size of the boiler. When I take the front cover off, I find a sticker that says "Installation incomplete unless rating plate attached here." Awesome. A call to the knuckleheads that put it in revealed that they don't have records that far back.



Anyway, I'm at Phase 1 of my steam heat redevelopment project--that is, I'm having all the steam traps fixed, the venting fixed, installing TRVs upstairs, fixing the condensate pump, etc.



I'm planning Phase 2 for next year. That will involve deciding whether to replace the boiler or to keep the current boiler and have the copper header replaced with a nice black steel drop header that will use both riser ports instead of just one (though W-M's current steam boiler manual says using the one riser is acceptable for some reason). Knowing the capacity of the current boiler will help me make that decision. I've measured the EDR in the house and determined that the acceptable DOE should be somewhere between 130 (using a .33 pickup) and 150 (using a .5 pickup).



Can anyone roughly identify the boiler model I have so I can call W-M? If there's a way I can estimate the size by taking a few panels off, that would really help me. Here's a few pictures:

ChrisJ

25K per tube

Going from memory I believe those burner tubes are 25K each so that makes your boiler 200K btu input.

That's assuming I counted right and that there are 8 tubes.



Personally, I'm against using a 33% pickup factor and recommend either doing none, or going with no more than 10 or 15% assuming all of your piping is insulated well and you calculated your EDR correctly.  If your radiation is oversized for your home which most are I would lean more towards little or no pickup factor.





That said, how does the current piping perform?  Any problems with joints breaking?

Waterbury Steam

8 tubes

Yes, you counted correctly. There's definitely 8 tubes there. I would say that the EDR is oversized for the house, as the radiators were installed in 1946 to handle the single pane windows. The previous owners replaced about half of the windows with double glazed and we'll be doing the rest sometime in the next five years. About half of the mains are insulated and I'll be insulating the rest before this heating season.



As for the current piping, it isn't cracking joints or anything, though I don't know how dry the steam is coming out of that header. I'm leaving everything with the boiler and header as-is for this next heating season so I can evaluate how well it performs when the rest of the system is operating properly.

BobC

Do it right

It sounds like you have a two pipe steam system, if that is so it should be running well under 1 PSI and that means it should have a vaporstat not a pressuretrol that I see in your picture. Anybody who used copper on a steam header probably did not waste any time with proper sizing of the boiler, I'll bet what you have is oversized by a good bit. Also make sure you really need a condensate pump, most house don't need them; to often they are installed to mask other problems that should be corrected.



Go through the house and survey all the radiation, list the radiators by room and if you don't have a radiator chart give us the following data.



Room

  # of tubes or columns across

  Rad width

  # of tubes or columns deep

  Rad thickness

  Rad Ht (floor to top)



From that we can calculate the EDR of each radiator and then the total EDR of your system. Usually you just match the total EDR to the closest match available in a steam boiler. The EDR rating on a boiler builds in a 33% pickup factor so you can select a boiler a little smaller than your total EDR assuming the piping is all insulated in the basement.



Then when the time comes you have to find an installer that will do a much better job on the installation.



Bob

Waterbury Steam

Yes, it's 2-pipe

Hi Bob--you're correct. This is 2-pipe system, but it's definitely not a vapor/vacuum system. I have the pressuretrol set at 1/2 psi with a 1 psi differential, which according to my research should be adequate. I consider a vaporstat a "nice to have" which I would probably add if I decided to go for a new boiler.



As for measuring the EDR, I'm already done with that. I have Dan's EDR and Lost Art of Steam Heating books and have already gone through every radiator in the house. I followed the method of sizing he recommends on pg. 75 of Lost Art of Steam Heating. If you'd like to see the results, check out the image I'm attaching here. I would not be surprised if the current boiler is oversized--I just need a way to estimate what it is.



You mentioned the condensate pump--I agree, it may not be necessary. My contractor is going to measure the B dimension and offer a fix, replace or remove recommendation.



A little background about myself and my chosen contractor may be helpful--I'm an engineer at an agricultural vehicle plant with experience in machining, heat treat, chrome plating and vehicle assembly processes. My contractor is experienced with industrial, commercial and residential steam and I got to know them when they rebuilt the refractories on 5 of my heat treat furnaces.

icesailor

Your Boiler?

This might be your boiler. If it is, here's the installation manual for it. On the last page of the manual, is the ratings for all models. If this isn't the correct one, go to the Weil-McLain website for boilers and click on "discontinued equipment".



http://www.weil-mclain.com/en/multimedia-library/pdf/weil-mclain-pdf/products/discontinued/discontinued-boilers/eg-peg-egh-boiler/egpeg1egh2manual.pdf

BobC

EG45?

It looks like the EG-45 is a a good starting point if your going to stay with that series of boiler. Your total is 408 sq ft and the 45 is rated for 392, as i said that includes a pickup factor so as long as the piping is insulated it should be about right.



Have your steam man look at the specs and see what he thinks. I tried to attach a pdf spec sheet but this site won't let me. Look on page 38 of this -



http://s3.supplyhouse.com/product_files/119-454-325-Install.pdf



IT ACTUALLY LOOKS LIKE THE PDF ATTACHED AFTER ALL!



Bob

Waterbury Steam

Thanks

Thanks, guys! I think the current one might be an EG-55 based on the number of burner tubes I see, assuming ChrisJ is correct that each one is rated for 25k btu. If that's the case it's somewhat oversized, but not egregiously so. I'll know if it short cycles this winter that I should be looking at replacement.

ChrisJ

Size

If it was my system, especially with all of those TRVs I would aim for an EG-40.



However, you have another alternative assuming the block is in good shape.  Have a 2 stage gas valve installed and do a low / high fire setup.  Chances are it would work beautifully on low fire and the high fire would get you steam faster.

I know very little about it other than Joe from Thatcher Heating and Cooling, known as Jstar on here has done it for a few customers.

KC_Jones

2 stage gas valve

Gerry Gill is a big fan of them as well.