Range Tribune Cylinder/Potterton boiler constantly firing

[Woody19763]

I've replied to an old thread about this in the hope that the person got to the bottom of it and can tell me what the problem was. We've been in our new build 5 years and can't get any satisfaction finding he fault.

It's an unvented pressurised system. If the water and central heating is off the boiler will still fire. The only way we can guarantee that it won't do it through the day/night is to turn it off at the mains.

We had a qualified engineer out last year, spent £300 getting him to service it all and look for the fault, he spent all day trying to locate the issue and reckoned it was a Danfos part (a valve of some sort) that wasn't shutting down in the airing cupboard (sorry I don't know the technical term). It was replaced, worked for a bit but now it's doing it again. I'm at my wits end with it, we got to a point where at least if the CH was off and the water was on the auto timer it wouldn't do it but last night it started doing it in the middle of the night. I don't want to keep throwing money at Engineer's who don't seem to fix the issue Anyone come across similar and can suggest what the issue may be? The wiring has been checked, twice.

 

[Gasguru]

Danfoss valves are prone to sticking.

Take the valve actuator off each valve (2 screws).

Check the spindle is free to turn.

The O ring on the spindle can fail, water leaks and they seize up. The spring in the actuator head is then unable to return the valve to the closed position and the heating/hotwater stays on.

The actuator heads can fail too with iffy microswitches.

 

[Woody19763]

Danfoss valves are prone to sticking.

Take the valve actuator off each valve (2 screws).

Check the spindle is free to turn.

The O ring on the spindle can fail, water leaks and they seize up. The spring in the actuator head is then unable to return the valve to the closed position and the heating/hotwater stays on.

The actuator heads can fail too with iffy microswitches.

Husband just looked and he says the valve's gone again, that's the third one in 5 years.... thank you

 

[Woody19763]

Any idea If there's another brand of valve that works better than that one, it's ridiculous that they don't last longer than about 12 months at a time....

 

[Gasguru]

Honeywell....much better design.