Hi, I have an Ariston presurised system and when the temperature in the hot water tank drops the boiler switches on to heat the hot water (as it should) however when this occurs the radiators are getting red hot, this started a while ago but is getting worse. I suspect the motorised divertor valve is sticking. Either that or the motor itself is playing up though i dont think so. Any idea from you experts out there.

Adrian, August 2009

Thanks Elanar i'll check it out.

Adrian, August 2009

Sounds like the Heating Zone Valve, or Mid Pos 3 Port Valve (whichever is fitted is letting by), Honeywell valves can be repaired using a new Ball Seal kit, Danfoss etc will need to have the whole body replaced, it would be worth checking the Actuator motor is not seized, but this is less likely

www.elanar.co.uk, August 2009