topic Re: 2 stage duel fuel heat pump in Nest Thermostats

2 stage duel fuel heat pump

Aloha_Ohana — Fri, 16 Aug 2024 06:36:58 GMT

I have a Gen 3 Nest Thermostat and have just installed a 2 stage duel fuel Trane heat pump. I noticed that during stage 1 of cooling, only the fan turns on, not the compressor. Then when the temperature creeps up to 2- 3 degrees of set temperature, it goes strait to stage 2 cooling. I also noticed that my equipment setting identifies my unit has conventional heat and I am not seeing a way to change it to a heat pump system.

Currently at my tstat, I have Y1, Y2, G, Rc, W1, W2, and C connected. Nothing at o/b, star or Rh.

1. Should my tstat identify my system as a heat pump rather than conventional and if so, how do I change this.

2. Am I wired correctly for a 2 stage duel fuel?

Re: 2 stage duel fuel heat pump

AxelD — Mon, 19 Aug 2024 18:28:26 GMT

Hi Aloha_Ohana,

Thanks for posting in the Community! It’s interesting that your system is a Heat Pump but there isn't any wire connected to O/B. That might be the reason why the Nest Thermostat is recognizing it as a Conventional System. To help troubleshoot this issue, please share photos of your previous and current wiring configurations.

Keep me posted.

Regards,
Axel.

Re: 2 stage duel fuel heat pump

Aloha_Ohana — Mon, 19 Aug 2024 19:22:07 GMT

Thanks Axel. It turns out it is user error. Trane makes two models of the same name and what was delivered and installed was the AC version, this the reason why the wiring diagram did not show an o connection

Re: 2 stage duel fuel heat pump

AxelD — Mon, 19 Aug 2024 20:07:50 GMT

Hi Aloha_Ohana,

Thanks for replying! I appreciate the update and the information provided about your Trane HVAC system, now that it makes sense that it doesn’t have an O wire.

Remember I'll be here for any further questions you may need.

Regards,
Axel.