PTAC blows out cold air for 3 minutes then shuts off

It sounds like your PTAC (packaged terminal air conditioner) unit is malfunctioning. When the thermostat is set to heating mode, the PTAC should be blowing warm air, not cold air. There are a few possible causes for this issue:

1. The PTAC may be low on refrigerant. If the unit is low on refrigerant, it may not be able to properly heat the air.
2. The PTAC's reversing valve may be stuck in the cooling position. The reversing valve is responsible for switching the flow of refrigerant between heating and cooling mode. If it is stuck in the cooling position, the PTAC will blow cold air even when the thermostat is set to heating mode.
3. The PTAC's heating element may be malfunctioning. If the heating element is not functioning properly, the PTAC will not be able to heat the air.

I recommend contacting a trained HVAC technician to diagnose and fix the issue with your PTAC. They will be able to determine the cause of the problem and repair it properly.

How are you determining that one section.is cold and one warm? If this is in fact the case you have a blockage in the coil or a compressor that is down provided this is a multi compressor unit.

The cold that you describe may be just unconditioned air? If you are certain you can hear the comp operating for a couple of minutes, and then the heat starts, I would guess it is a reversing valve issue if it's a heat pump and it probably is. Or the control board acting up. I've had a lot of issues with the boards in the Amanda PTAC units. I can't remember how to configure it, but if you Google "Amanda ptac configuration", there is a lot of info online. May try a reset method first. Hope this helps!

bad switch, bad motor capacitor, bad motor.

it depends on thermostat setting. compressor might be going off on a safety.

I would just ask the landlord the same question you asked us. It should always blow warm air if it is working properly.

I think your PTAC is under charge, if the air filter is clean and the evaporator is also clean together with the blower. Check the freon charge and refill if suction pressure is below 50psi and discharge is below 190 psi.

May be your thermostat setting wrong. If corrected check the heating coil.

freon is low or outside is very cold

Onl full service comes to mind.