Do I have a faulty programmer?

[mav]

I appreciate this question may get asked several times, but after having searched the forums, I haven't found the answer to my particular problem.

I have a Glow-worm Micron 50FF boiler with the integral programmer fitted to a Y plan heating system. I have recently had a new 3 way valve and tank stat fitted. The room stat is a Drayton roomstat.

Everything on the water side seems to be working ok, the problem comes when I turn the heating off on the programmer. As soon as the room stat is turned up or the temperature drops, the boiler will fire up and pump starts running.

The heating side of the programmer appears to have no effect at all. Is the programmer faulty? It's less than 6 months old.

Thanks in advance for any advice.

Mav

 

[oilman]

It might be, or it might not.

 

[kevplumb]

have you always had the problem
or since you had the valve and stat changed

 

[Gas2Air]

The fault you describe is a stray 60-90 volts backfeeding on the grey (hot water off) wire in the 3 way valve to your programmer, enough as i say to backfeed and bring the pump and boiler on.

GlowWorm have a resistor built to stop this. It's connected on the mains inlet to your Micron, best advice contact GlowWorm.