trv

s watkins

can i put thermostatic rad valves on a one pipe system

Brad White_200

Yes but....

not the type which are piped in place of the single hand valve. Rather, you would use a variation of that, know informally as a "Thermostatic Radiator Vent Valve".

Essentially, you remove the radiator air vent (often an angle pattern and opposite the hand valve).

The TRVV screws into that tapping where the vent was and a new vent (usually a straight, not angle pattern air vent) is screwed into the top of the TRVV.

The way it works is simple: If the room is warm, the thermostatic head keeps valve is closed and it prevents the air from being vented and in so doing, prevents the steam from entering.

You will still gets some steam (entering to the extent that it can compress the air within the radiator), but a fraction of what you would normally.

If the room is cool (below the thermostatic head's setpoint), the valve is open and the radiator will vent normally.

What is key to any of these is that they have an integral vacuum breaker to allow air to re-enter the radiator and system between cycles. If the TRVV isolates the air vent, it also isolates the vacuum-breaking function.

Macon Controls model "OPSK", (Sweden), and Danfoss (Denmark) make these with integral vacuum breakers. Others may but I am not sure.

You being in the UK, naturally the thread pattern should be verified to BSPT for your market. I am sure they are available.

You can see that if such a valve replaced the angle valve, if closed, you would not be able to drain back the condensate. These TRVVs are so much simpler.