Combi boiler stat not turning off heating

[Deleted member 120897]

Thanks just trying to find the wiring diagram. I think Live is 1. Neutral 3. Switch live 2. ?

No:

1 should be live in
3 should be switched
2 should be Neutral

Wiring diagram usually on the reverse of stat cover.

 

[Matt0029]

Thank you

 

[Matt0029]

No:

1 should be live in
3 should be switched
2 should be Neutral

Wiring diagram usually on the reverse of stat cover.

Thanks what Shaun said to test makes more sense now!

 

[Matt0029]

Test terminal 3 to earth or neutral with stat off should be no voltage

If there is 240v check 1 if that’s got 240v aswell stats dead

To to check I'm on the right track. Testing 3 (switched) to earth or neutral with the stat off. A reading of 0v. Shows that no volts are passing though the circuit i.e no call for heat at the boiler?

 

[ShaunCorbs]

Correct but I have seen them wired backwards eg 3 live 1 switch

 

[Deleted member 120897]

Correct but I have seen them wired backwards eg 3 live 1 switch

Yep, me too. Had one recently, set to a mid point, so in winter it’s fine. The way it was wired max was off and low (5 degrees) on the VRT30 was off.

 

[Matt0029]

Correct but I have seen them wired backwards eg 3 live 1 switch

Thank you!

 

[Matt0029]

Correct but I have seen them wired backwards eg 3 live 1 switch

Thanks of wired backwards at the stat it would still work? I know if get the wires wrong when swapping a boiler at the boiler side the stat comes on when turned down and off when turned up.

 

[Matt0029]

Test terminal 3 to earth or neutral with stat off should be no voltage

If there is 240v check 1 if that’s got 240v aswell stats dead

If that stat was dead, would that cause it not to knock off the heating. As is happening. Thanks

 

[ShaunCorbs]

Yes they can stick eg on all the time

 

[Matt0029]

Yes they can stick eg on all the time

Thanks even though it is making the clicking sound when going above/below cut of temperature?

 

[Deleted member 120897]

Thanks even though it is making the clicking sound when going above/below cut of temperature?

Yes. I’ve had some fail brand new out of the box.

 

[Matt0029]

The stats wires for some reason had been pulled out of the boiler not sure why. How old would be a pro combi he100 be around 10 years old?

 

[Matt0029]

Pro combi is a vokera?