Oversized boiler

speedbird

Hi everyone, trust this isn't the first oversized boiler post. We've been in our house now since the end of 2013, so our 3rd winter. By and large we love our heating system. It works great, feels great, and is very quiet, low pressure too; and we've been told "they did a great install" by a local steam guru, when he was examining the pipes around the boiler.

The same local steam guy also said they installed too large a boiler (apparently not uncommon, given a variety of reasons I've come to know and understand). I initially called him to try see if I could insulate the pipes in the basement, given I want to build a workshop down there and it's just too hot. He said, given the size of the boiler it would short cycle even more than it already was, and less heat would get to 2nd and 3rd floors. House specs: 4500 sf, 18 radiators, 3 floors, weil-mclcain egh-85 boiler, 349k btus output. He said I could do with something more like 225-250k btus, that would give me longer, more efficient cycles. He also mentioned there was some new device / adapter to decrease the "size of the flames" on burners, but didn't have enough data points on the cost benefit / impact?

Is there anyway I can get my basement cooler, and my 2nd and 3rd floor warmer? There's already a hot water system hanging off it going to heat blowers in kitchen (after a remodel). Can I do something similar to make hot water for bathrooms, to at least make it more efficient?

My novel idea is to insulate the pipes, turn off one or two of the radiators on the 1st floor, keep thermostat at 69, have it work a little harder, and push more steam upstairs; while hoping it balances out cost wise, given won't be wasting heat basement. I did an experiment and it seemed to work (without the insulation component). I turned off two radiators on 1st floor and the 2nd floor was much warmer upstairs, while 1st floor was still 69.

Sorry for the long winded explanation. Hopefully, my goal is clear. Happy to answer questions. Again, we have a great system - just wish it wasn't burning as much fuel.

Dave0176

Of the 18 radiators did you figure the steam square footage aka EDR. That gives a better understanding on boiler sizing.

nicholas bonham-carter

Is this a one-pipe system, or two?
I would insulate the pipes, and check your main venting.
Post some pictures of the boiler and its piping
There is no sense in turning off some radiators, until you know what really needs to be done, like main venting.--NBC

BobC

Oversized boilers are all too common but they can be made to heat the house evenly. Is this one pipe or two pipe steam?

If it's single pipe steam it's a matter of getting the venting balanced, if it's to pipe it's time to make sure all the traps are working right.

In either case insulating those pipes will make the boiler cycle more but that isn't the end of the world. My old v73 was rated at 3X my EDR and that boiler worked just fine and my cellar was 55 after insulating all the piping.

Post some pictures of the boiler and the piping around it and show us a sample of the radiators showing both ends.

Bob