High head normal vaper line in heat only

Hello Guest

You neglected to mention whether the machine was functioning correctly, before changing the service valves. If You can provide a little more information it would be appreciated.

I will check with a friend tomorrow who has been having similar problem with a Bard heat pump, and see if he has resolved the situation. He has normal pressures in cooling mode, and sporadic high-pressure readings (410 a system) in heating mode. The machine will seem to be functioning normally, and then he will have a return service call for compressor lockout.

I have recently run into check valves that have been damaged in installation by overheating in carrier units. Without further information my best suggestion would be to check the function of any check valves, and confirmed they are installed in the correct direction.

Hopefully my friend has resolve this problem (almost afraid to call him I may get goaded into a service call, if he hasn't.) . If I have any new information I will post it tomorrow.

70 psig suction in the heating mode seems high.68 dgr oa temp is also quite hi. What is you indoor coil air entering db/wb. What is your air leaving temp. Do you have required air flow. Low air flow will cause hi indoor coil press. The only thing a tev knows is super heat. Check your superheat before suspecting your expansion valve. How are you weighing a charge on a split system. Is the ah and the outdoor unit of the same seer rating.

Guest,

You're posting in the wrong forum.

Try Hvac-Talk.com

Best regards

I ran into this once. What I found was the backup heat source was before the evaporator coil, in this case a gas furnace heat exchanger. When the heat pump was running and the back-up heat came on the head pressure would shoot way up. I set it up where the compressor wouldn't run during back-up heat and then had to set a delay to where the compressor wouln't kick back in until the heat exchanger had cooled down enough not to drive up the head pressure.

Is there anything that could be introducing an unusually high heat load before the evaporator coil?