Heater always on

[TnRox]

I have the vintage ac and heater kit on my roxor and when I turn the air conditioner on it will it will blow hot air out and not blow cold for several minutes and will not get all the way cold like it will before the roxor fully heats up

 

[Jgeib]

Do you have the 12v ball valve on the hot water side to the heater coil? If yes, its not closing to shut the water off to the heater side.