What seemed like a good idea at the time has turned into a real problem!
We have an old Honeywell room thermostat - not sure of the actual model but this is a picture:
It was working ok - we are just about to decorate the room and decided it would be good to replace it with a more modern looking one.
I disconnected it from the circuit and made a note of the wiring. The colours seemed a bit wrong but it worked and so assumed it must be right.
Note wires are only connected to 1, 4 and 3 and looking from the back we can see the colours:
So Blue is on 1; Yellow on 4 and Red on 3
Looking on the diagram inside the cover, we can see that 1 is Live; 4 is the switched Neutral and 3 is the Neutral.
This is where I think the colours are wrong as I would have expected Red to be Live but it works so must be correct.
I intend to replace this with a Drayton Combi-stat RTS8, the wiring for this is:
So, I connected the Red wire to N; Yellow to 3 and Blue to L. Turned on the power and when turning the dial right up to 30 nothing happens - the boiler doesn't fire.
I put a meter on L and N and it showed 240V but when putting it on L and 3 is showed nothing. To test the unit, I disconnected and measured the resistance between L and 3 when turned to 0 degrees - it showed no connection but when turned up to 30 it showed 0 ohms, so I believe the unit works.
I did also connect the wires to a ring mains tester and it said the L & N were reversed, so I swapped the Red and Blue wires round but all that did was blow the main heating circuit fuse!
I don't see what is wrong - wish I hadn't started!
We have an old Honeywell room thermostat - not sure of the actual model but this is a picture:
It was working ok - we are just about to decorate the room and decided it would be good to replace it with a more modern looking one.
I disconnected it from the circuit and made a note of the wiring. The colours seemed a bit wrong but it worked and so assumed it must be right.
Note wires are only connected to 1, 4 and 3 and looking from the back we can see the colours:
So Blue is on 1; Yellow on 4 and Red on 3
Looking on the diagram inside the cover, we can see that 1 is Live; 4 is the switched Neutral and 3 is the Neutral.
This is where I think the colours are wrong as I would have expected Red to be Live but it works so must be correct.
I intend to replace this with a Drayton Combi-stat RTS8, the wiring for this is:
So, I connected the Red wire to N; Yellow to 3 and Blue to L. Turned on the power and when turning the dial right up to 30 nothing happens - the boiler doesn't fire.
I put a meter on L and N and it showed 240V but when putting it on L and 3 is showed nothing. To test the unit, I disconnected and measured the resistance between L and 3 when turned to 0 degrees - it showed no connection but when turned up to 30 it showed 0 ohms, so I believe the unit works.
I did also connect the wires to a ring mains tester and it said the L & N were reversed, so I swapped the Red and Blue wires round but all that did was blow the main heating circuit fuse!
I don't see what is wrong - wish I hadn't started!
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