heat pump with Nest E thermostat stops cooling

[eddo]

I switched from a Honeywell T4 thermostat for my Diakin Heat Pump to a Nest E thermostat. I have no problem with the T4 controlling the system but when I change to the Nest thermostat I cannot keep the cooling mode working. When I first turn the system on in the cooling mode the blower comes on and the thermostat does the normal count down before turning the outdoor condensing unit on... the condensing unit runs for about 60 seconds then shuts off. It will not turn on unless I turn "system mode" to off then on again and let the count down begin again, as before it runs for about 60 seconds then shuts off. My system has Aux heat. could the problem be the "Heat Pump Balance" setting and the "Lockout or Breakpoint" temperatures?

Thank you for any assistance. I had to change back to the Honeywell T4 thermostat to keep the unit operating.

[Markjosephp]

Hello eddo,

I'm sorry for the delay in response, and thank you for taking the time to let us know about your inquiry.

It appears that you're experiencing power-related issues when activating your AC. If the Nest thermostat receives less power than it needs, this could cause your system to short-cycle. But I'd love to know more about this; could you please share with us your thermostat's wiring setup? If your Nest Thermostat is still installed, please gather its power readings in the Technical Info settings. Also, have you tried turning on your heating system? Does the same issue occur?

I'll look forward to your response.

Regards,
Mark

[Jenelyn_O]

Hi there,

Thanks for your help, Mark.

@eddo, chiming in — I just want to check if you're still encountering the issue. Please let us know as we'll be willing to assist you. 

Best,

Jenelyn

[Jenelyn_O]

Hi eddo,

I'm just checking in to make sure that you've seen our response. Please let us know if you have any other questions or concerns, as I'll be locking this thread in 24 hours.

Thanks,

Jenelyn