Potterton Profile Boiler switches off when turned down

[maccow]

I Have a Potterton Profile boiler which is about 15 years old. Every time I turn the heater down it switches off so I can only use it at one temperature, when its turned up full! Its been like this for a few years now and other than this it works fine and has passed its boiler service.
Im going to move out & let out the house so have to get it fixed soon.
Im just wondering if anyone knows what could be the cause & how much I might expect to pay to have it repaired.

 

[45yearsagasman]

When you say "turn the heater down" what are you referring to? A better description of your system would help.

 

[ianniann]

I assume you are turning down the flow temperature? It would be normal for the boiler to turn off if you do this because it will be above the new set temperature, but it should turn back on again after a few minutes when the water has cooled to the new setting. Does yours stay off forever? What sort of level are you turning it down to?

 

[Agile]

To make the situation clear could yo turn the boiler stat down to about "2" and then turn of the heating from cold and tell us what happend.

You say its "passed its service" but a service is not something to be passed or failed.

I expect you have had a Gas Safety Certificate done but that is not the same as a service and a stat problem would not be noticed in most cases.

Tony