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Controlling daikin Heat pump and Hot water boiler/Heating with single thermostat

msimm15 Member Posts: 3
Hi I am researching ideas to have a single thermostat to control both my Diakin Mini Split AC and my gas boiler. The Daikin units allow for installation of a wired thermostat - the DAikin Envi which is essentially an Ecobee Smart SI redone specifically for Daikins mini split but with only 6 main terminals - 2 for data, and 2 for power + 2 extra for aux heat (also 24vac).

I am thinking of using the 24vac backup heat terminals to control the zone valve associated with the room where the mini split is. I have a taco 6 zone control panel controlling the boiler.

1 - Would I be able use the 24Vac from the aux heat on the thermostat to control the zone valve ?
2 - Can I connect directly to the zone valve ?
3 - Do I need to use an isolating relay for the zone valve ?
4 - What is the voltage of the data wires from the thermostat going into the taco control panel ?

I believe the Daikin Envi allows you to program when the aux heat should kick in based on temps so I would really just have the envi call heat from the boiler when its below 35 degrees or so.

I found 1 write up on line of another person suggesting something like this a few yrs back but it didnt say what happened or if it worked.

The other thing I was thinking was to have the 24Vac from the aux heat line control power to the 24vac thermostat controlling the boiler which should work but would make the thermostat itself go on an off to frequently causing to restart each time.

Any input or direction would be appreciated.



  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,512
    As the Daikin system is so brand specific in its parts, maybe their technical support system would be better able to answer this question.—NBC