Got one driving me crazy

[swamprunner]

Ok here it goes... I got one driving me crazy.This is a heatpump. In a dentist office the hyg. area the grils are turning on the heat in the morning then turning on the ac when in the afternoon. They call me in the afternoon and say the ac is not working. I changed out the compressor about a month ago and sometimes when I go to check it out the pressures look great. But the compressor is tripped out on hi temp. or tripping the breaker. I went out yesterday and replaced the dryer filter. Pulled a new vac and got the pressures set. For sh** and giggles I pulled the guages off and connected to the unit beside the one I was working on to verify the pressures and both were the same. Any suggestions on what the problem could be?

[KB Cool]

Maybe a floating restriction. But, the tripping the breaker doesn't make sense. How's the fan motors? Any side to side play? wiring look good? Check run cap on compressor too. Especially, if it has a start assist.

[TXTech1]

Have you checked your high volt lines for a skinned wire or short of some sort? possible loose connection/grounding wire on the high volt possibly?

[air1]

Not enough information here to be of any help. What did you check? Did you cycle the reversing valve and check in both heat and cool? Amp draws and voltages? Are you weighing the charge in?

[HighlandThunder]

I had a 410-A split-A/C once where the condenser was on the ground and the coil on the third floor. Pressures looked great for the first 10-15 minutes of run time, then the head would start to steadily climb until the bypass opened. Whole problem was just overcharge. Just a thought.

-Brian

[JMack13]

What was the reason for changing the dryer?

[Andr00]

If I had a tripped breaker, I'd have immediately checked the cap just to rule it out.

[davidlanthony12]

It seems you are saying it works in the morning in heat mode and not in the afternoon when calling for cooling. Sounds like it might be a reversing valve issue.

[Brent Ridley]

Check your condenser coil. Make sure you have a clean coil. Also, make sure you have plenty of clearance for the condenser to get proper air circulation.

[rglasgow]

Don't know which heatpump you have but if heats in morning and want cool in afternoon; look for high head pressures. Could be simply dirty filters. During heating the compressor trips breaker and auxiliary heat keeps the office warm. Turn on cooling and nothing. They call you.

[captaincallback]

Heat pumps are strange animals. Does your condenser have a low ambient kit? If so, did you verify that it's cycling on and off correctly. I would also look at reversing valve and defrost cycle.

[SBKold]

All these responses and no one asked the obvious.

Recip compressor with indoor txv in cooling with no start kit.

[Brent Ridley]

Sb might be onto something. Please post model and serial of unit for both the HP and AHU.