Zoning Steam

Stewy_2

Anyone ever seen or attempted to zone steam? If I could isolate the upstairs and downstairs on their own mains, is there a product/devise that could be installed on each main and controlled by separate thermostats to open or close as necessary, when the call for heat is made? It seems like a very simple concept to me, if you can close off a main and not give the steam a way out, then you could control that main. It would almost act like a circ pump. Any thoughts?

David Nadle

Look at thermostatic radiator valves. Danfoss is one manufacturer. TRVs are particularly easy to add to one pipe steam because you just replace the vent. I installed one in each upstairs bedroom and reduced the overheating that would occur during the shoulder season.

John L

T R V's

I have seen the Danfoss brochure for the RA2000 trv andit says to be used on one pipe hot water and 2 pipe steam. Can the be used on 1 pipe steam?
John L

David Nadle

Yes

Danfoss makes a one pipe steam adapter for the RA2000 series. You need the adapter, a steam vent (1/8" NPT straight, not angled), and the sesnor/actuator.

Jack_44

an amateur's reply

Don't use zone valves - use TRV's. If you zone at the boiler, you MUST add a condensate receiver and return pump (if I understand the issues). Far simplier and far more flexible to do the zoning at the rads. Less to fail, lower reliance on electric grid, just generally more beautiful.

Jamie Hall

John's right...

although you can use zone valves, they are likely to be much more expensive and much less flexible -- and you have to be sure that even when the zone valve is close the system can still have the proper venting and returns (it can be done; I've done it).

The other warning on zone valves is that they must, repeat MUST, be full port when open. Gates or balls, full pipe diameter (not reduced through the valve and then back up). Otherwise, believe it or not the steam just won't get by them in any usable quantity even when they are open (please don't ask how I know...)