Stat wiring, I've adjusted

grandfortune · Nov 19, 2018

Hi all,
Have I wired this right, adding underfloor heating to a S plan opened the stat to check connections and it was just wired to the right hand side stat only I've re done it to the picture so the brown goes Rob the limiter first, that right?

Cheers grand

[ElectriciansForums.net] Stat wiring, I've adjusted

Taylortwocities · Nov 19, 2018

They are in series, so it don't matter.

PS, the left hand limiter needs earthing too!
PPS, the blue conductor needs to have a brown sleeve on it.

MDJ · Nov 19, 2018

PPPS Don't forget to ensure the flex outer sheath is inside the stat

Taylortwocities · Nov 19, 2018

Just to check:

we are looking at the temp controls for an unvented tank (Megaflo, etc)?
And that bit of flex is part of the DHW control circuit?

davesparks · Nov 19, 2018

Yes both stats must be in series, only having the right hand stat connected was dangerous, you've done the correct thing there.

Those units are normally double insulated so connecting the earth is not necessary, but if you are going to connect it then connect it to both metal bits, not just one.

davesparks · Nov 19, 2018

Are you sure it's an S plan system as there appears to be a black wire connected to the DHW off terminal of the stat, this would suggest a Y plan system.

If it is a Y plan system then you should confirm that the necessary additional 2 port valve for the overheat protection has been installed. If the installer didn't connect the overheat stat they may have ignored other essential safety devices.