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I am currently having to turn my boiler off at night via the fused spur so that it doesn't run all night, as it seems to be constantly on even though the programmer is timed off.
I have a 10 year old Y-plan system with Glowworm boiler & Drayton mid-position valve. I recently had a problem with the boiler sparking but not lighting but that was resolved with a new gas valve. No wiring has been compromised to my knowledge.
I have read that the Drayton MPV is prone to get sticky microswitches, which can cause the orange wire to stay live & thus keep the boiler/pump on. However, with this said (& after some time reading/understanding about the principal/circuitry behind this type of valve) I can not see how there would be a live at any of the Grey, White or Orange control wires if the programmer is timed OFF. Sure if the programmer is ON & CH is timed ON (white is live) I can see that a stuck CH only microswitch will also feed live to the the orange wire thus keeping the boiler on - but as said the boiler stays on with the programmer OFF.
The programmer appears to be OK (I am no expert with these things) but having taken it off the wall & checked the pins with a meter. The relays are both in the off position & stay there until I switch CH or HW on, whereby you can hear them click on (with programmer back on wall of course & mains on). Boiler stays on even with programmer taken off the wall so I assume that rules out any programmer fault.
What can be causing the boiler/pump to stay on ? The boiler is in the garage & although I am having a garage conversion done at the moment I don't think any cables have been damaged (& wouldn't that cause the RCD to trip or fuse in the boiler to go ?) - I do have a frost stat next to the boiler that the builder accidentally knocked the front dial off - I don't know if he has upset that - it was/is set at it's minimum setting (3 degrees).
Is the frost stat designed to fire up the boiler even with the programmer off (now that I am writing this I think the anwser must be yes as that is the whole purpose of the frost stat) ? How do I check that this has not been damaged ie. what measuremets should I be getting on the frost stat ? Can it also be taken out of the circuit now that the boiler will be in a warm room so frost stat will be pointless anyway.
Sorry for the very long post - just trying to give you guys as much info as possible.
Thanks in advance
I have a 10 year old Y-plan system with Glowworm boiler & Drayton mid-position valve. I recently had a problem with the boiler sparking but not lighting but that was resolved with a new gas valve. No wiring has been compromised to my knowledge.
I have read that the Drayton MPV is prone to get sticky microswitches, which can cause the orange wire to stay live & thus keep the boiler/pump on. However, with this said (& after some time reading/understanding about the principal/circuitry behind this type of valve) I can not see how there would be a live at any of the Grey, White or Orange control wires if the programmer is timed OFF. Sure if the programmer is ON & CH is timed ON (white is live) I can see that a stuck CH only microswitch will also feed live to the the orange wire thus keeping the boiler on - but as said the boiler stays on with the programmer OFF.
The programmer appears to be OK (I am no expert with these things) but having taken it off the wall & checked the pins with a meter. The relays are both in the off position & stay there until I switch CH or HW on, whereby you can hear them click on (with programmer back on wall of course & mains on). Boiler stays on even with programmer taken off the wall so I assume that rules out any programmer fault.
What can be causing the boiler/pump to stay on ? The boiler is in the garage & although I am having a garage conversion done at the moment I don't think any cables have been damaged (& wouldn't that cause the RCD to trip or fuse in the boiler to go ?) - I do have a frost stat next to the boiler that the builder accidentally knocked the front dial off - I don't know if he has upset that - it was/is set at it's minimum setting (3 degrees).
Is the frost stat designed to fire up the boiler even with the programmer off (now that I am writing this I think the anwser must be yes as that is the whole purpose of the frost stat) ? How do I check that this has not been damaged ie. what measuremets should I be getting on the frost stat ? Can it also be taken out of the circuit now that the boiler will be in a warm room so frost stat will be pointless anyway.
Sorry for the very long post - just trying to give you guys as much info as possible.
Thanks in advance
