Ecotec 637 Plus always "on"/showing heat demand

[Tom Green]

Hi

My Ecotec 637 has recently started being "on" the whole time, even when there is no demand for heat. It thinks there is (the radiator symbol is constantly on), and so is maintaining the system to temperature.

The heating & hw system (honeywell evohome) isn't calling for heat, and it still continues to run even when both systems are set to "off".

I have checked the wiring and see no signs of loose/crossed/shorted wires.

Is this an electronic fault with the boiler? Any other thoughts before I get an engineer out?

Thanks

Tom

 

[Steelmasons]

Link wire has possibly not been removed...call someone..

 

[Dan Robinson]

Link wire is option number one.

When you say the controls are off, are you sure the boiler relay is off?

How is Evohome configured? Who configured it? And when was it set up?

 

[Tom Green]

Hi

Thanks for this. In looking to answer your questions (checking the signal from the boiler relay etc) I eventually diagnosed the CH motorised valve. It was sending a live signal to the boiler when the controller wasn't calling for it. There was some debris in the microswitch which I cleaned out and that seems to have fixed it. However now the valve itself doesn't seem to be closing (this may or may not have been the case before I took it off to check it).

Either way, the problem is solved for now (I have the towel rail on while the hot water is on) and I'll replace the valve head and should be fully back in business.

Thanks!

Tom

 

[FurstyFerret]

Just personal opinion but I'd suggest replacing the valve head. Once the microswitch sticks once, it'll stick again.

 

[Tom Green]

Thanks- yes am going to replace the head now.
Tom