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Replacing manual Thermostat.

I have a Solar heat pump system fitted. This has a manual 3 speed fan coil thermostat with a setpoint control.
I can control the heat pump by it's timer but not the fan coil. When the heat pump is switched of the fan continues to run unless you manually switch it of. Similarly when the heat pump comes on in the morning you have to manually switch on the fan coil. Can anyone recommend a solution where I can switch on the fan automatically.



  • LanceLance Member Posts: 142
    Your information is too little for me to be specific but this may help. You can wire in a fan relay to operated the fan on a specific speed when the heat pump turns on/off. Relays come in various voltages.
  • WobblerWobbler Member Posts: 3
    Hi Lance

    Thank you for your reply.
    Not really sure how to accomplish that, I have attached details of the heat pump circuit board and the thermostat.
    My problem as I see it, is the thermostat works independently from the heat pump and the only control it has is the high temp setpoint. I could achieve better control albeit without fan speed with a central heating programmer and room stat. I find it hard to believe that air source heat pumps do not have a equal control.
    Please let me have your thoughts.

  • SherlockOhmsSherlockOhms Member Posts: 13

    Not sure what you have for equipment, there is a bit of options for various applications, here is a typical heat pump wiring, I saw no wiring on your info.
  • SherlockOhmsSherlockOhms Member Posts: 13

    This is the bigger picture beyond the thermostat.
  • WobblerWobbler Member Posts: 3
    Hi SherlockOhms
    Thanks for your post.
    My problem is the thermostat supplied with the system does not have enough controllability see attached PDF file showing wiring for HL108DA2/DB2. This will not allow me to control the fan by the heat pump or by a timer. I have to manually switch it, not good for waking up to a cold house of blowing cold air all night.

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