weil mclain boiler

Bill_40

I am in need of replacing a very old (30-40yrs) Weil Mclain G11-1 boiler. It is a 225,000 Btu/hr input with a 6" vent. I need as much information on this boiler as I can get and if I can replace it with a more efficient and less Btu/hr boiler. Please help.
Thank you

Constantin

You need to provide more information than that.

How about:

1) Do you have steam or hydronic heat? The former requires a steam-capable boiler and needs to be sized according to the radiation surfaces in the home. The latter needs to be sized according to heat loss.

2) What kinds of heat emitters are found in your home? Radiators, radiant floor heat, base board, convective, hydro-air coils, etc.

3) What kind of fuel do you use?

Ask and you shall receive. Cheers!

Bill_40

weil mclain info

Sorry about that... first time here.
It is an old copper radiant system in the celing of a 3000 sq ft home. Natural gas hot water boiler.

Constantin

No Worries, Mate!

I think your ceiling radiant system is very interesting indeed. We may see more of that in the future, as radiant cooling may be on the rise. Plus, as long as you maintain the chemistry in the water of your system, it'll outlive both of us.

I forget where exactly the temps are for a ceiling radiant system (I'm a mere homeowner myself). However, I would like to think that if the house is insulated, weatherized, etc, that you could use a condensing boiler with your set up. That would pay for itself in a number of years due to the gas savings and it can heat your domestic water very efficiently via an indirect water heater as well.

I would start off with a heat-loss calculation to determine just how much heat you're losing on a so-called design day (the 95th or 99th percentile in terms of outdoor temps). In Boston, such a day is -15°F. This in turn will dictate the size of your heating plant for heating purposes. Depending on the shower fixtures, hot water needs, etc. it is not unusual to see heating plants that also serve indirect water heaters to be upsized just to meet the hot water needs...

For example, our house is slated to use a oil-fired Vitola VB2-40, which is a 146kBTU/hr boiler. According to two, independent heat loss calculators, the maximum heat loss the house will experience is around 100kBTU/hr. The reason we went with a larger boiler is so that we could have faster recovery for the potable hot water tank. Multiple bathrooms, the prospect of teenagers, and all that.

You can derive your heat loss either with a computer program or by looking at past fuel bills. If you're really geeky like me, you'll do the heat loss using a free program like the Slant Fin "Free Heat Loss Calculator". Good contractors will do a detailed heatloss for you. You can also estimate your heat loss based on fuel usage.

To do this, take your fuel bills for the last year and see how many therms of gas you used. Then see if the fuel company included degree days on their calculation or not. If not, call up the local weather station and get the actual degree days for the last year. Plug that info into the enclosed Excel spreadsheet.

If you use gas for cooking and/or water heating (i.e. a separate gas water heater), use the summer months as a means of figuring out how many therms you consume on a baseline basis. These therms should be subtracted from every month for your gas usage. For example, if your gas usage in August is 14 therms and your annual gas usage is 1000 therms, then the therms used to heat your place were

1000therms -12months x 14therms/month = 832 therms.

The enclosed excel spreadsheet allows you to simply input the summer months usage, it does the rest for you (i.e. you don't have to calc out the years worth, it does that for you).

When you're calling your local weather station for the heating degree-days info, also ask them for the typical design day temperature, i.e. the 95th or 99th percentile low temp for the region. Or plug in the coldest ongoing temp you can think of in your area.

Lastly, the excel program asks for the AFUE rating of your old boiler. This is info you may be able to get from Weil McLain, either online or with a phone call. There are many excellent boilers out there and I hope this was a bit of help. Cheers!