Potterton Puma 80 malfunction

[scm]

Hello, for the last few days my boiler decided to have a life of his own! When I turn the hot water tap on for a few minutes and then turn it off, the central heating switches on even though the boiler switch is only on hot water!!! The radiators become hot and the boiler switches off only after a few minutes.
Could anyone tell me what is possibly wrong with it? Thanks :?

[sunbeam]

Re: Potterton Puma 80 malfunction

diverter valve problem.

you could change the whole valve but they are expensive, the last time i bought one it was around £85.00 + vat but they're not bad to change,

inside the valve on a puma there is a wax capsule and it is this that has gone,

if you shop around you should be able to just get the capsule,

but if you're going to change the wax capsule inside the valve,make shure you get the pin (on the capsule) inside the hole (inside the bottom of the valve)

[scm]

Thanks for the advice.