DIY Doctor UK DIY Forums

I have a Gloworm Potterton boiler feeding a central heating system with a hot water tank. Now there is a fault .. the radiators work ok but I have no hot water. If I ONLY have the hot water on (CH off at the control unit), the radiators still get hot and can not be controlled by the room thermostat. I feels like the hot water is only getting to the radiators but not the hot water tank.

Reading similar posts on this forum it looks like a valve is stuck but I don't know what that valve would be called or what it looks like, or where it might be located. Any help/suggestions would be welcome.

Google "uk-plumbing.com/danfoss-randall-3-port-mid-position-valve-hs3-22mm-p-1398.html?zenid=36867889c7b2f7b8eef2e3c01455355"
It look something like this and is probably near the system junction box, or programmer if that is being used as a junction box, often in the cupboard with the tank.
I have known the actuator( the bit on the top) to fail and cause this problem, and it is usually replaceable without draining the system, as it is held onto the valve by screws or nuts. it comes prewired at the actuator with a short 5 core cable, with standard colours, which will need to be replaced in the J/B-Programmer.
Only if the valve is actually stuck, rather than the actuator not operating it would you need to change the copper/brass fitting on the pipework.
HTH

Your guess will be better than ours - it's your house.

Check near the pump, for a T shaped valve with a white or silver motorised head fitted - change motorised head.


htg