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Re: Steam Boiler Sizing (Convector radiators)
Correct, you could have used the next size smaller, but you are not drastically oversized. And the EDR numbers may be a little off if your cover dimensions are different than the ones I posted.
The only down firing you can do on the boiler is to reduce the gas pressure no more than 12% and that is not a recommended procedure. It is just something I know will work from experience.
You have the 4 section boiler and the EG-40 already has the smaller firing rate (the 45 has the higher firing rate) and perhaps lowering firing rate more may save you a small fraction on your gas usage. The problem with adjusting the gas pressure lower is that the efficiency of the actual flame will also go down. So there is a sweet spot where the lower flame size will be less efficient but the lower input will counteract that loss of combustion efficiency. The Laboratory at Weil McLain has already done those tests and have determined that the boiler you have is best set at 125,000 BTU Gas input on the low end and 150,000 on the high end (EG-45).
Going any lower than say 112,000 BTU input may actually be less efficient and cause the gas usage to go higher. Any savings you might realize from your fiddling with the gas pressure will only be in the 2 to 3% range anyway, not worth the risk. …And you need a technician that has the time to play with it and check the adjustments with a combustion analyzer. Do you have a friend with a combustion analyzer? Otherwise you will need to pay for a pro with the proper equipment to do these adjustments for you, If your total annual gas bill is $1000.00. And you pay the technician over $150 for the service to do the adjustment, your savings will be about $20.00 a year.
So unless you are experiencing a major short cycling issue, I would leave it alone.
Re: Lingering return pipe noise ... poor venting?
Whoa. OK. Two pipe steam system. How are the traps on the radiators? Are they functioning properly? It can be a little hard to tell, but with the heating system going and the radiators full — hot across — the outlet from the trap should be warm to hot, but noticeably cooler (at least 5 degrees cooler) than the inlet from the radiator to the trap.
Additionally, all the dry returns — return lines above the boiler water line — may be warm, but none of them should be hot.
Check the rest of the piping. If there any low level return lines — near of at floor level — they must be below (preferably at least two to three feet below) the water level in your condensate tank. If not, any drips (pipes coming down from a steam main to one of these pipes) must have a trap on it (might be an F&T, but could be thermostatic) and that trap needs to be working.
Re: Steam Boiler Sizing (Convector radiators)
This one is 60.3 of my measurements are correct.
There are adjustments based on the cabinet dimensions and the actual cast iron dimensions. This is the chart I am using and you can see if the cabinet size changes the amount of the heat output changes a little for the same size cast iron convector.
As you can see on your 68" long radiator, changing the cabinet hight by just 2" can change the EDR up to 4 Sq Ft. That is why I need you to doublecheck the measurements
Re: Steam Boiler Sizing (Convector radiators)
OK in the book that is a 20" radiator. 4" legs. 18 sections = 40.5 EDR
Re: Steam Boiler Sizing (Convector radiators)
Here is the first calculation. Based on these measurements the EDR for this convector is 28.9
If the measurements are different please correct me.
Re: Short cycling boiler. I'm stumped.
Put a ball valve with a tee that has a boiler drain on it between the valve and the tank. If the tank has pressure in it and you shut the valve off and unscrew the tank, that water under pressure will be spraying out everywhere. The boiler drain will allow you to drain the pressure from the tank while keeping the rest of the boiler under pressure.
Webstone makes fittings designed for this application. They are designed for expansion tanks and have the ball valve and drain together on one fitting.
Definitely something to consider once you get this other problem with the power venter taken care of.
Good job @EdTheHeaterMan for all the help he's provided.
Re: Musings on the "Design Day"
@DCContrarian is technically right about the percentile bit. And statistically it's actually even more complicated… I was just trying to get across a general feel for it.
One other minor item… in a sense that 95/99 stuff is a measure (not that good a one) of the variability of temperature — how often and how far it moves from the annual average. That variability actually seems to be increasing (and climate modelling shows it should) with the result that those design temperatures probably are too high (too warm). But that, folks, is a whole other can of worms!
And yes, @ethicalpaul , I have lived in places where the heating system couldn't hold the indoor temperature up. Of the houses I've lived in, I can think of three which couldn't.
Re: Musings on the "Design Day"
My current house. Built 1922. We renovated the 1st floor 20 years ago; the 2nd floor is original wood lath and plaster. Replaced a coal fired converted to oil 1.25GPH Nozzle Thatcher Gravity with a 100,000 BTU/h WM Boiler. Zoned 1st 2nd floors.
Eastern Isl of long design 5°F. When near that and the NE wind begins to blow the couch gets pulled away from the 2 in the wall radiators, the wood cover by the stair's radiator gets removed and the boiler runs probably 100%. When it's at 0°F or below we maintain 65 inside overnight. Once the sun comes up so does the house. Thats close enough for the 1 or 2 times we've lived here with those conditions.
I remember growing up Summer curtains came down and Winter curtains went up. I'm sure that would help here.
pecmsg