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Option discussion for oversized 1 pipe steam boiler
I will give just a quick background here. There is additional background in an earlier post last year: https://forum.heatinghelp.com/discussion/166807/2-stage-gas-valve-setup#latest
I have a one pipe steam system with Weil McClean EG-65 that is not facing any serious problems but I am trying to see what I can do to try to get a little better gas use efficiency due to it being significantly oversize. The calculations have been done and reviewed on previous discussions on this forum and I am anywhere from 33% to nearly 50% oversized depending upon whether a few radiators are shutoff or not. The main venting capacity is quite good, pipes are insulated, pigtail is clean and system is balanced throughout the house. Only real issue is very cold days short cycling a bit on pressure or just cycling off on pressure. Typically pressure is
1) Downfire the burner
2) block one or two of the burners (10-20% overall reduction)
3) Get a 2-stage gas valve and vaporstat and have the gas valve reduce gas flow based upon sensing pressure rise via the vaporstat
4) Alter the thermostat cycle time in some manner (I.e. what would be best setup for an oversized boiler condition?)
5) Unisulate some of my pipes in the basement. I didn't see any efficiency improvement when I went and insulated everything (gas use per heating degree day) in the first place 4 years ago. Basement and some of the floors on the first story just got a bit cooler. I had insulated all my returns as well at the time...
Of course welcome to additions to the list. Right now I have a heating guy suggesting I do #2 (block a couple burners). He wasn't willing to do the 2-stage setup anyway (says if not recommended by manufacturere then he could be liable...). Seems to me blocking vents wouldn't be too different in that regard but valid point is that it is easily reversible.
I wonder about thermostat possibilities. Most of the time when I know my boiler is starting to build pressure my thermostat is already reading the target temperature... why does it keep calling for heat?
I will apologize if I don't answer responses right away tonight since I have a function. Will plan on spending some time tomorrow though. Appreciate anyones input.