Solved: Heat blowing cold air and only when fan is turned ON

Gr33ngi4nt — Sun, 10 Dec 2023 21:25:20 GMT

Hello, I have the nest thermostat (purchased in 2023) and have been having a lot of problems getting it set up. My HVAC uses a heat pump and my old existing thermostat did not have a C wire. The wires connect to the old thermostat were Y, G, R (with jumped to Rc), and W/OB. I have already installed the Nest Power Connector and this is working. Afterwards, I connected the Nest with G, R, Y and OB wires. Now, when I turn on heating, the condenser runs (the compressor I think is located outside on the roof of my low rise building) but the fan does not. The only way to get the fan turning on is when I manually turn the fan to ON. Even then, while the compressor runs I am only getting cold air blowing despite being in heat mode. I have tried switching from O setting to B setting (we have two HVAC systems and I noticed the other system specifically used a B wire) and this had no impact on the heat nor the fan situation. The C wire I've connected is correctly getting 24v. I don't understand what's wrong as everything seems to be set up correctly. Please help!

Moderator edit: Subject updated for clarity and findability.

Re: Heat blowing cold air and only when fan is turned ON

Gr33ngi4nt — Wed, 06 Dec 2023 00:33:31 GMT

Nevermind the fan does turn on after a few minutes of waiting. However on cool or heat I only get cool air coming from the the unit despite hearing the compressor turning on

topic Re: Heat blowing cold air and only when fan is turned ON in Nest Thermostats

Solved: Heat blowing cold air and only when fan is turned ON

Re: Heat blowing cold air and only when fan is turned ON