Hi out there - has anyone ever wired a HY01BW thermostat - the problem is I have 3 wires - yellow, red and blue - I also have 3 terminal which are NO, COM & NC. does any one know which wires go in which terminal please. 
HY01BW thermostat wire problem
- Thread starter cheeriodeerio
- Start date
Hi thanks for replying = I am about to remove an old dial thermostat with a new touch screen, the problem is the new thermostat has 3 different terminal markings from the dial. the touch screen terminals are com, no & nc. I know that red is live and blue is neutral but don'tknow where to fit them.
Heating forum would be appropriate place to post [not all stats use a neutral].
the 3 colours you say are used will not mean anything much but the red is likely to be the live one & the blue the neutral (but assume nothing, you should check at the boiler or local junction box using a voltage tester which is live & which is neutral), if there are 3 wires then its likely to be a 240 supply on the old thermostat & 1 is the 240v live feed, 1 will be the switched return wire & the 3rd will be the neutral that gives the neutral for the heat expectation heater on the old stat.
if the instructions you have with your unit are the same as the ones I had DO NOT wire as it shows or you will blow the relay contacts apart. the instructions I had show live on the Common terminal & neutral on the N/O
it should show live on common & the switched return on the N/O the neutral is NOT USED & can be disconnected at its source then cut back at the thermostat.
some boilers use a volt free switch but they will only have 2 wires going to the thermostat.
hope this helps
if the instructions you have with your unit are the same as the ones I had DO NOT wire as it shows or you will blow the relay contacts apart. the instructions I had show live on the Common terminal & neutral on the N/O
it should show live on common & the switched return on the N/O the neutral is NOT USED & can be disconnected at its source then cut back at the thermostat.
some boilers use a volt free switch but they will only have 2 wires going to the thermostat.
hope this helps
You need to verify this yourself, but the red wire is most likely live, yellow wire is most likely switched live, and the blue wire is most likley neutral.
If the wires are as described above; then the red wire goes to COM, the yellow wires goes to NO, and the blue wire is terminated safely in a connector block.
AGAIN, verify what the wires are and identify the live and switched live wires.
Elliott
If the wires are as described above; then the red wire goes to COM, the yellow wires goes to NO, and the blue wire is terminated safely in a connector block.
AGAIN, verify what the wires are and identify the live and switched live wires.
Elliott
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