Radiators hot when central heating off and thermostat at 0

[jenni75]

Hi i have an ideal classic se12 ff and when the hot water is on and the central heating is off and thermostat in the room is set to 0 the radiators are hot.
Is this normal, or is there a problem that needs fixing?
Thank you for any replies
Jen

Yes, either that stat is faulty or there is an internal fault in the boiler, if you have a rotary type stat you should be able to hear a low click when the stat is turned indicating the room temperature. Get a Gas Safe registered engineer to check the boiler and stat asap.

Sounds like a pipe has been connected incorrectly. I had this and to get things reset. Basically the hot water should only go to the hot water tank but if connected incorrectly it goes to the radiators too. Get a good plumber round and they should be able to sort it

It almost certainly isn't a fault with your stat or an internal fault with your boiler. It might be a pipe connected incorrectly but if it's been working before and has just started causing problems then it's probably a fault with your three port valve. This is the valve that controls where the hot water from the boiler goes. It can send it to the radiators, the hot water tank or to both.

It's either stuck at "both" or the motor that drives it may be dead. How good are you at DIY? If you know where the valve is get a screwdriver and take the motor unit (grey box) off the top. Get someone to switch between the settings on the boiler (hot water only, heating only then both) and check that the motor turns. It will turn just enough to turn the valve a few degrees.

If the motor is fine, use a mole wrench or similar to gently turn the valve spindle. If it won't turn then the valve is jammed.

Replacing the motor is fairly simple. You just need to disconnect it (turn the electrics off first) and connect a new one.

Replacing the valve is more difficult as it normally involves draining down the system.

DO NOT attempt to repair a gas boiler yourself, it is illegal to do so, all work carried out inside a gas boiler must be carried out by a GAS SAFE REGISTERED ENGINEER.