Zoning a 1-pipe steam system

Supply House Rick

in this case, if it were my house, i would put thermostatic radiator valves on the radiators i wished to slow down. i would also want my system to be in very good condition and state of maintainance:
low pressure-12 oz.
extremely well vented mains
good boiler piping[as per mfg's instructions]
clean water quality
good thermostat location and adjustment-no setback

TRV's could be affected by any of those faults, but will work in this situation.
any sort of zone valve will cause changes of behavior in the system which may have as brad says"unintended consequences"

get a copy of "the lost art of steam heating" here for more discussion on zoning.--nbc

David Moseley

zoning a 1-pipe steam system

I have a client with a large 2 story house heated with 1-pipe steam. They don't live in (hardly ever use)half the house, and they wanted to see about installing couple of zone valves and not heat heat the part of the house they seldom use. This would be easy enough to do, a zone valve in each of the 2 mains leaving the boiler. Is this a good/bad idea? I'm concerned about the boiler cycling on pressure with only one zone calling, and they may end up with poor heating and no energy savings. Any comments?

Kool Rod

Why not use TRVs? The lowest setting on a TRVs is around 43 degrees and this helps keep things from freezing. With a 1 pipe system each TRV has to have a vacuum breaker.

I have half my house shut off this way during the winter.
- Rod

Unknown

TRV's

I service large residental steam system with zone valves. The home owner was sold a bill of goods that never worked as promised.

TRV's = Control

Zone Valves = Trouble