Why is it 10 degrees hotter on my second floor?

gmurphee

Hi.  My husband and I live in a house built in 1897 with single pipe steam heat.  We're encountering a problem we've never had before.  Even though the thermostat is set to 66 or so downstairs, it gets as high as 78 degrees upstairs.  (We know this b/c we recently had two zone central air installed, along with a handy thermostat on the second floor).  While normally we would just suck it up and open a window (like we used to do when we lived in a prewar apartment building) we have a 6 month old infant in the house, and we're concerned for her safety (it can be dangerous for infants to sleep in such warm conditions).  It's been so bad some nights that we've had to turn the theromostat way down on the first floor and run the air conditioning on the second floor just to cool off the second floor.  We've had two technicians out.  One didn't know what the problem was (and I'm pretty convinced didn't have a clue about steam heating in general), and the second, while knowledgable, didn't fix the problem.  He cleaned out the pigtail regulator, which was really clogged with debris.  This seemed to fix the problem at first, but now a week later we're back to square one (with the A/C running at 3 a.m.)  Any thoughts?  Is the only solution to install a TRV?

Jamie Hall

Thank you

for moving this one -- although I did read it on the main Wall.



Balancing single pipe steam can be a bit tricky.  However, venting is the first place to look.  First, are the mains well vented?  The way to check that is to see if they heat right to the ends, nearly as fast as the radiators near the boiler start to heat.  If they are really slow, then consideration should be given to putting some main venting (or more main venting) on the ends of the mains.



Having checked that, the next thing to look at is the vents on the radiators.  There are two directions to go here; both may be required.  The areas which are heating too fast may have vents which are bigger than they need to be.  If they are adjustable (there are a number of good makes -- and a few lousy ones) you can try closing them down some.  That should slow the radiators down where it is getting too warm.  If that doesn't fix the problem, you can look at the radiators where it is not warm enough, and try opening up their vents or putting bigger ones on instead.  There is a caution here: it is possible to vent a radiator too fast, at which point it will become noisy.  You don't want to do that.  This may solve your problem.



It may not, too.  In which case, the solution is to put thermostatically controlled vents on the too warm radiators -- NOT TRVs (thermostatically controlled valves).  TRVs aren't meant for one pipe steam, as the valve to the radiator must be always open so any condensate can return.  However, thermostatically controlled vents are made.  They sense the local temperature, and close when it gets too warm, thus preventing steam from getting into the radiator.



Hopefully that should do it...

David Nadle

TRVs

TRVs have a few parts. There's a valve body, and a thermostatic actuator. For one-pipe steam with the Danfoss system you use the same actuators, but instead of replacing the valve body you attach the actuator to a vent adapter. Ordinarily I'd say that Jamie's warning about the potential confusion in referring to TRVs with one pipe steam was overcautious but I think we did have a post here a while back where somebody made this exact mistake...



The good news is that because of the vent adapter it's quite easy to add TRV(ents) to one pipe steam. But you should try to identify the vents on your radiators and post that information here. There may a way to rebalance the vents so the first floor heats faster and the second floor slower. How would you rate the heating performance and comfort on the first floor?

gmurphee

Thanks

Thanks so much for the help!  The heat on the first floor works really well, not too hot, not to cold.   We already have devices on the radiators upstairs to try to slow the steam...they are turned to 1 and it is still getting way to hot.  I'll talk to my heating guy about trying the TRV(ents) and see if that helps. 

Rod

TRVs

Hi- I have the same problem with my one pipe steam system. I have an old house with a big open stairway in the middle. While it is comfortable downstairs, the heat rises and makes the upstairs unbearable.  I installed TRVs on the upstairs bedrooms and they work great!  Make sure you get the type for one pipe steam which other have mentioned goes between the radiator and the air vent. Both Macon and Danfoss make TRVs and they are both high quality. I've attached a pdf of some information on TRVs for another homeowner which may be of help to you.

- Rod