hot water / radiator fault Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[karlmarks]

Hi; i have a gas central heating boiler that heats water for the radiators & hot water. When the boiler comes on to heat just the hot water the radiators start getting hot too even though the room stat has not clicked in. If i switch the hot water off and the rads on, the rads do still get hot.
Any ideas, cheers

[htg engineer]

Check 3 port valve.

htg