Programmer says "OFF" but boiler remains "ON&

[Elephant_Guy]

I have recently developed a problem with my Potterton Netaheat 10-16 and Gloworm programmer.

Despite the programmer's manual switches being switched to the "Off" position the boiler continuously fires up and heats hot water. The central heating system seems unaffected and the radiators remain cold. the boiler continues to heat hot water until the correct temperature is reached, the thermostat cuts in, switching off the boiler for about 10 minutes before it starts up all over again.

It's driving me potty (sorry!!).

The only way to stop the problem is to turn off the programmer power supply at the mains which prevent's the boiler firing up.

I have tried replacing the programmer front but the problem remained the same. After a suggestion from a previous post I checked the motorised valves but they all also appear to be working correctly.

Any ideas ?

 

[gazthepottertonengineer]

yes sounds like your motorised valve switch is stuck on

wot have you got i.e 2 port or 3 port

 

[Elephant_Guy]

I have 2x2 port valves.

 

[gazthepottertonengineer]

check them as one of them will be stuck in the on position

 

[Elephant_Guy]

Many Thanks. I will look a bit harder...

 

[ollski]

There won't be anything to see just the microswitches sticking on on the hot water actuator. Try taking the head off if its possible and moving the valve itself by hand just to make sure its not that which is sticking.

 

[Elephant_Guy]

Many Thanks Gaz and Ollski

Finally worked out it was only the motor in one of the 2 way valves, £15 in B & Q sorted it out.

Appreciate your help in getting an idea where the problem was, I really didnt have any idea where to look first and you saved me a lot of time and money

Thanks again.

Eiephant_Guy

 

[kevplumb]

should have looked here

 

[Elephant_Guy]

Doh!!!!

Will look at Screwfix first next time Kev.

ta