Central Heating will not switch off

Hi,

We switched on our central heating briefly the other day (Boilermate III & Potterton Suprima Boiler) The heating works fine but will not switch off! We usually switch the central heating to 'on' using the switch on the timeclock on the boilermate III and use the thermostat to control the heating (turning the thermostat down to 10 degrees when we want to switch the heating off). However the heating stays on and does not respond to the thermostat in the hall. I switched the heating to 'off' on the boilermate III timeclock - But the heating is still on and we are swealtering!!!

Does anyone have any ideas ?

Many thanks

If it does not respond to timer or stat as in turning off.
Check 3 way valve.
If not Main PCB looks to be at fault.
Check pages 21 and 22 in the book.
Mike
MGC/H2O
Norfolk

I share the same problem, a Boilermate III and a Potterton Suprima (40 i think).
Everything used to work fine, we have the Central Heating set to on on the electromechanical clock and the thermostat in our hall would control the CH, obviously all through out summer the thermostat been set to lowest setting and therefore Radiators have not been on (the thermostat light would always indicate "Reached"). However we had our boiler serviced a few days ago and when the boilerman left I noticed the radiators were on! I first checked the thermostat and saw he switched it to 10. I intermediately turned this down as far as it would go (as we usually have it set). After a good few hours the radiators still would not switch off and were still really hot.
I then changed the switch on the Boilermate to CH off. Still the Radiators will not turn off. I've ended up having to turn each radiator off for the time being. I contacted the person who serviced the boiler and he said I had to turn the Temperature knob to "off" on the Potterton Suprima! I thought this controlled the temperature of the water leaving the boiler! I tried doing this and it has stopped the radiators heating up if I turn them back on, but we are left with lukewarm water and a red light on the Suprima so I don't think this can be right! I've since turned this knob back on so we get hot water again.
I'm not sure how it can be working one day, then our Suprima gets serviced and then our boilermate no longer works the way it should!

Hi;
Your hot water was all ok the summer.
Used no heating?
To service the boiler did the guy have to isolate it?
Yes and sometimes the supply switch operates the boiler and the BM III
Depending on who put it in etc etc.
Guy done his job then checked all was ok.
Normal and good practice to do so.
Would think the answer may be as my post above.
The boiler temp control has nowt to do with it.
Have you the book?
Down load one for free at Gledhill.
Try switching the BM III off, wait a few minutes then try again.
Mike
MGC/H2O
Norfolk.