How to wire replacement thermostat (Ed.)

[PIERRE 1961]

Hi all.

Im trying to convert my thermostat from a old Honeywell T6360 analogue stat to a new Honeywell DT90E.

The wiring consists of [ L brown] [ neutral black] [ boiler switch on white] [green earth] NO C wire.

Im trying to fit the DT90E as follows from a youtube video also going by the wiring instructions enclosed.

The video shows that neutral and earth arnt needed,so i terminated them to choc block and poked back into the wall.

The video then shows fitting the live to terminal A and the switch on wire to terminal B,which the diagram seems to show also. im told the batteries power the screen.

Upon doing this its blowing my boiler isolater switch fuse upon re energising the circuit.

Anyone have any idea whats wrong.

 

[Murdochcat]

If it’s blowing the fuse you have introduced a dead short

 

[PIERRE 1961]

i gathered that, but not sure how as its wired as per video and wiring diagram.
its apparently only a two wire connection

 

[RandomGrinch]

Can you show us a picture of how the old stat was connected, and the wires as they are now?
Which wires were connected to terminals 1 and 3 of the T6360?

 

[PIERRE 1961]

Hi ive managed to figure out the problem.I was led to believe the grey/white wire was the switching wire as many sites state.Ive found out that is actually a neutral.What i presumed was the black neutral is actully the switch wire. If i was the original installer i would have put black/blue tape on the white/grey wire and maybe red tape on the black wire.The stat seems to be working ok after a rewire.Many thanks for previous posts for gettting me back on track

 

[RandomGrinch]

i would have put black/blue tape on the white/grey wire and maybe red tape on the black wire.

It's never too late to leave sleeving on the wires. You might save the next occupier a nasty shock
Well done for sorting it.

 

[JohnD]

No offence meant, but when you said

The wiring consists of [ L brown] [ neutral black] [ boiler switch on white] [green earth] NO C wire."

The truth is that

"The wiring consists of brown, black, white, green."

As you now realise, the colours of wires cannot be relied upon, so you have to test and identify them.