Central heating/hot water programmer fault

[griswald1999]

Hi, I've a very old Potterton EP2000 programmer that has begun to misbehave. It seems to be that the power bypasses the programmer so that the boiler is on all the time.
The slide buttons that advance the program or switch the program off/auto/once/twice etc have no effect at all - power remains on at the boiler.

However, the central heating pump will not work unless the led shows that the central heating is switched on.

Before I order a EP2 replacement, could it be any other component that is having an effect on the programmer and causing it to behave this way?

Thanks in advance

 

[ollski]

Sounds like tour clock has probably had it but not your main fault.

 

[45yearsagasman]

Before I order a EP2 replacement, could it be any other component that is having an effect on the programmer and causing it to behave this way?

Quite possibly yes, but you tell us nothing about the rest of your system, not even the boiler make.

 

[griswald1999]

Boiler is Worcester Danesmoor 20/25 - cuts out when cylinder thermostat dictates, so seems ok
Two rads upstairs (working fine)
Six rads downstairs (working fine)
Cylinder seems to be storing hot water just fine.
Two Honeywell valves (silver box things) in cylinder cupboard seem to be ok (one replaced last year)

The only way to turn the system on and off is to use fused switch at side of program unit.

What else do you need to know?

 

[ollski]

Suspect your hot water valve may be sticking.

 

[griswald1999]

Suspect your hot water valve may be sticking.

Thanks for your response. How can I check this valve?

 

[ollski]

Check for voltage on the orange wires in the wiring centre with a multimeter. If you dont have one take each orange wire out one at a time and make safe and then re-introduce the power and see which one stops the pump running.

 

[griswald1999]

Check for voltage on the orange wires in the wiring centre with a multimeter. If you dont have one take each orange wire out one at a time and make safe and then re-introduce the power and see which one stops the pump running.

Thanks, didn't need the multi-meter - gave the valve a very gentle tap and 'wiggled' the slider. Heard a sort of gurgle and the programmer now works properly.... so not faulty.

I'll get my local heating engineer to replace the valve asap.

Thanks again for your help, much appreciated.