AC Not Turning On

[stephenPSP]

Trying to install a Nest learning thermostat in my apartment.  I believe my HVAC is a one stage air conditioner with an electric heating plate add on.   Used to have an Ecobee thermostat and needed their power adapter (PEK) to make everything function correctly.   This is what the wiring looked like with the Ecobee.

 

 Had a basic Honeywell thermostat installed while I ordered the Nest thermostat.  The wiring looked like this. 

 when j installed the nest thermostat using this configuration, the blower turns on but it never calls on the compressor to start so the air never gets cool.  Not sure where to go next.   I did buy the nest power adapter just in case. 

[Vito2]

Similar question here: Got a new Daikin 2-stage cooling, 1-stage heating electric HVAC,  model DZ9VCA4819. Daikin thermostat has 4 wires: R, C, Data1 and Data 2. Connected it per color codes to Nest Thermostat (red, blue, yellow and white), but AC Not Turning On. Where did I go wrong?

[Patrick_Caezza]

@Vito2 

Your thermostat uses a propitary interface that is not compatible with any Nest thermostat.

[Patrick_Caezza]

@stephenPSP 

Going by the original thermostat wiring I see it is a cool-only system as there is nothing connected to the E terminal which is used for heat.

Look at the terminal block on the control board in the furnace/air handler to verify the thermostat is wired correctly.