TRV's on every radiator

BIRDCAGE1

Hi All,
I'm looking into placing TRV's on all my existing radiators and I heard something today from colleague of mine that its normal to leave one rad with a normal valve, something to do with a time delay between all the TRV's shutting off and the boiler actually stopping ....... not 100% sure on the actual reasons for this. Is this normal practice and would I be doing any harm not leaving a rad with a normal valve?
thanks for any feedback...

No7

Fitting TRVs on all of the rads can lead to a situation where all of the valves close while the pump and boiler are running.
This is not desirable for the pump as it uses the water to keep its bearing from overheating and burning out.

A by-pass is required to prevent this. A by-pass can be either:
A. a radiator with no TRV that is always left open,
B. An internal by-pass in the boiler that opens when low flow is sensed. Check your boiler manual.
C. A self-acting valve that opens when it detects a high static pressure(indicting low flow) across it. Inexpensive and available from plumbing providers

BIRDCAGE1

Cheers No7, I'd never heard of this issue with the TRV's . I think leaving the bathroom TRV free is probably the best option for me.

sullzz

Dont fit a trv in the same room as a room ( wall) stat , or your bathroom/ ensuite