I have amana ptac that blows warm air, and one part blow cold air. no error codes

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.

sounds like the auxillary heat strips are coming on and off....what kind of time does it cycle on and off?

This indicates FREEZE PROTECTION. Please look up an operator's manual on your particular model. A quick download you will find easily.

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

if the fan switch is in the Run position and not the auto position you are getting cool are when the heat element is not on. this is kind of like a way to circulate the air. look for an auto setting it then should only come on when needed. Keep in mind it is normal for the fan to start blowing before the heating element is warmed up, this prevents it from over heating, or coming on when the fan is not working

The thermostat is bad or out of adjustment.

freon is low or outside is very cold

the board or the heater need to be replaced

Onl full service comes to mind.