gas boiler

[Tricky]

Thanks again, Tricky. Good tip about the sticky switch; I'll check that. There's a couple of other motorised valves too; I will look at those as well.

 

I intend to spend a few hours with a multimeter and a copy of the Honeywell Sundial S Plan schematic as soon as I can. Judging by other parts of the house (previously owned by a 75 year old widow with a succession of boyfriends who did odd jobs) Bodger was the requisite title of anyone working on it. All of the components are Honeywell bar the boiler so it should be simple-ish. It is complicated a bit by the second boiler and two frost stats, but I think I can see round those with luck.

If you go to wiring centre the orange wire is the switched live, so if your programmer is off these wires should be dead. Be careful though as even when the programmer is off the grey wire to each zone valve is a permanent live. You may have a synchron motor that's failed. With everything turned to off go to each zone valve and check to see if the valve is wide open by checking the lever on each. My bet is one will be stuck open, if so a motor is around 10 to 15 quid a fiddly but easy 15min fix. Just make sure power is off at the fused spur (should be 3 amp).

If you need to speak to me I'll pm you my number.

Rich.

[Man On The Clapham Omnibus]

If you go to wiring centre the orange wire is the switched live, so if your programmer is off these wires should be dead. Be careful though as even when the programmer is off the grey wire to each zone valve is a permanent live. You may have a synchron motor that's failed. With everything turned to off go to each zone valve and check to see if the valve is wide open by checking the lever on each. My bet is one will be stuck open, if so a motor is around 10 to 15 quid a fiddly but easy 15min fix. Just make sure power is off at the fused spur (should be 3 amp).

If you need to speak to me I'll pm you my number.

Rich.

 

Thank you Rich, I may well take up your kind offer. It's unlikely that I shall get to do it for a while as it's actually working but in a rather unconventional way. I'll put a watch on this thread to keep access to it.