I have a LENNOX heatpump with a newer replacement RHEEM outside unit,
due to a gas leak at the coils of the original LENNOX unit. It works
fine in AC mode, but when it switches to heat, the compressor gets VERY
hot over time, and the accumulator starts frosting up from the bottom
up. It's a dual fuel, and I switched it over to gas, and the icing
leared up almost instantly. In heatpump "heat" mode, the air at the
registers is only about 75deg. I'll have to switch it back to heatpump
mode to see ig that's happening all the time, or just when the
compressor is heating up.

I'm thinking the defrost board might be wacky, but not sure .. .. anyone
got opinions ??