Central Heating Controller Problems

[Barry Ward]

Can anyone help. A couple of nights ago my RCD for the house tripped and I traced it back to the heating and water controls. I have an acl lifestyle controls and a Baxi solo bolier. I have tried replacing the controller but get the same fault. The RCD always trips out after 4 seconds. I have wired in the boiler seperately and it works and I can get hot water but the CH doesn't seem to work and the boiler overheats. The programmer was wired in with the boiler power as well and not just the thermostat and cylinder thermostat. ANY IDEAS ?

 

[IanDB]

I have wired in the boiler seperately and it works and I can get hot water

So that bit's OK then.

but the CH doesn't seem to work and the boiler overheats.

Looks as though the fault is in this area. You could try and isolate items further into the system. Try the CH actuator valve, that's about all that's left.

 

[Barry Ward]

Asking a simple question: Is that the same as the multi postion valve and how can I check its OK

 

[IanDB]

Yes. I don't know what valve you've got so I can't be specific. It could be that the motor has gone short circuit (or close). The motor drive is normally supplied by the brown (switched live from thermostat) and blue (neutral) wires. If you disconnect these you could try the system again to see if it trips. The orange and grey wires provide the switched power to the pump once the valve is in the correct position.

If those wire colours don't tie up, make a note of where your ones go and only then (!) disconnect to see if this is where the fault is.