My old air conditioner thermostat broke down, so I bought a new one. But when it arrived, I was horrified to discover that the terminal of the wires were not named the same. Both thermostats have similar controls:

  • Temperature (wheel)
  • Fan controls: auto/cont on the old one; speed on the new one
  • Cool/Off/Heat

I have four wires coming out of the wall. In the old thermostat they were connected as follow:

  • Blue wire: R/1
  • Black wire: Y/6 :
  • Green-Yellow wire: W/7
  • Brown wire: G/8

In the new thermostat, I have the following terminals: C, O, L, N, H, M, L

The old thermostat is a "T8376B1000 roca t40". The new one is a "dh 11.804".

I join some pictures: The notice of the new one (don't have and don't find on the Internet the one for the old one)

The notice of the new one (don't have and don't find on the Internet the one for the old one)

The old one is below

The old one is below.

Does anyone know how to wire the new one? Are they compatible ?

Thank you, any help would be much appreciated.

  • 1
    What make and model is the air conditioner indoor unit? Commented Oct 8, 2017 at 13:08
  • @ThreePhaseEel it's a "Roca". A spanish brand. I don't know the model because it's not visible (kind of hidden in the ceiling).
    – Legisey
    Commented Oct 8, 2017 at 15:33
  • What voltage do you measure from R to G at your wiring? Commented Oct 8, 2017 at 15:43
  • @ThreePhaseEel I'm sorry, I'm not equipped to measure that :S
    – Legisey
    Commented Oct 8, 2017 at 20:25
  • 1
    borrowing a voltmeter would indeed help you determine the wiring Commented Oct 9, 2017 at 22:21

1 Answer 1


Noting that the new one includes fan speed control and the old one does not, I'm going to say you bought the wrong model of thermostat.

Motor speed control isn't something that can usually just be added by changing the thermostat. It would require specific wiring and motor change in the air conditioner.

Completely disassemble the old thermostat, and examine the circuit board to get its model number and order using that.

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