How do I know which end of the rad is the lockshield valve?? Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[winkle93]

Really stupid question, I know....but I have no thermostatic valves on any rads in our house (7 rads in total). The system needs balancing but I don't know which are the thermo valves and which are the lockshield valves. How can I tell??

Thanks for helping.

[htg engineer]

One will be a wheelhead (can be turned on and off by hand) and the other a lockshield - the cover needs to be removed for adjusting.

htg

[winkle93]

Ok thanks for that but all the rads had wheelheads at both ends when we moved in!! I think I've sussed ot out now though, I'm guessing the flow pipe will heat up before the return pipe when the heating is first switched on???

Also, is it possible that the boiler pump needs adjusting so that it has enough power to supply the 3 extra rads that we had installed to the system? If so, is that something I can do myself?

[plumbbob]

You are right in suspecting the flow side will warm first when the heating is first switched on.

The pump will not always need adjusting when adding additional radiators, but if they are not warming increasing the speed may be a solution.

Pump speed is controlled by a three position switch on the side of the pump. It is usual for pumps to be run at the highest setting so you may find the speed cannot be increased further.

If the pump is at a lower setting there may well be a reason for this and increasing it may cause problems such as over pumping into the header tank or from air being drawn into the system.