I have a Baxi Solo HE boiler and a honeywell ST9400 programmer. I have an intermittent problem where if the water is on sometimes the heating comes on even if the thermostat is down. The light on the programmer for CH will be off but the radiators are hot. You can move the CH switch to off or override but it just keeps working. There is no way to stop the heating other than switching the water to off. With the water off the heating can be controlled perfectly with the buttons on the controller and thermostat etc.
I have had a plumber out who changed the switching valve and then an electrician changed the programmer so these parts must be ok
Does anyone have any other ideas please as I don't know what else to do?
Thanks
FMT
I have had a plumber out who changed the switching valve and then an electrician changed the programmer so these parts must be ok
Does anyone have any other ideas please as I don't know what else to do?
Thanks
FMT