Just moved in and have a Rheem Heat Pump. In heat mode the fan runs constantly and after a little while the reset button on the condenser trips. I reset the condenser unit by pushing the red reset button and after a while it trips again. I suspect a dirty inside coil check it. It is very dirty where you can't get to it. Slide coil out and clean it from underneath. Very difficult. Finished start it up and it runs through it cycle a couple times and I go to bed. Wake up the condenser has tripped again. Plan to check pressures after work. Didn't check them earlier because of the dirty coil whick will skew the pressure readings. I work on air conditioners don't know much about heat pumps in heat mode. Anyone have suggestions to what is tripping the reset button on the condensing unit. It is a split unit and the condenser fans and compressor run after it is reset. I don't know the history on the unit. I get heating from 70 degrees in to 94 degrees out with the heat pump while it is working.

Checked pressure in heating mode. High side went to 450psi it pegged the low pressure. Put high pressure gauge on low side and pressure built up to 400psi and then I shut it off. Switched to air conditioning. Ambient temperature around 60 degrees, High side around 150 psi dropping and low side around 75 psi and dropping. I think the reversing valve is screwing up. Does anyone agree or does anyone have any other ideas?