Nest Termostat and Heat Pump Heating instead of Cooling.

[ConstantinV]

I've had the Nest Termostat for many years. Last year has a AC Condensor replaced with  a Heap Pump. No major problems but a bit of a hassle to setup Nest to work properly, but it worked fine in the winter, afterall. Recently I had to disconnect the outside wiring to the heat pump and reconnected them today, per the original connection schema. When I started the system I started getting hot air instead of cool. The Heat Pump is blades do not spin very fast though...I've read previously posted solutions for similar issue and followed instructions to no avail. I have changed the Settings from O to B, but then the Heat Pump stopped completely. Please help with a solution. Thanks

[sicsacol]

Hi @ConstantinV,

Thanks for reaching out to the community page. I understand your heat pump is blowing hot air instead of cool air when using your Nest Thermostat, especially after replacing your previous system. I appreciate the relevant information provided and the troubleshooting steps you've already tried, including checking the O/B orientation and rewiring your system. Don't worry, I'd be more than glad to assist you. To better support you, I have a few questions for you:

• What type of Nest Thermostat do you have? To check the model, please visit the next article: How to tell which Nest thermostat you have.
• Does the issue also happen with heating? 
• When you turn on the cooling, are there any error messages on your thermostat display? If so, what are they exactly?
• Could you please share a picture of your current wiring installation? 

Any additional details you can provide will be helpful.

Cheers,
Jonathan