Heil heat pump not working.

[pinkertonpv]

I have an 8 year old Heil 5 ton Heat pump. I replaced the fan blower motor two years ago and the condenser fan motor this past year. All capacitors were replaced when the motors were. The compressor will not come on. The outside condenser fan will not run. The inside fan operates normally and blows air thru the house. Thermostat is a Honeywell deluxe programable (also 8 yrs old) and appears to be operating normally. When operated in the heat mode, thermostat is calling for aux heat. Aux heat strips are not being energized. I believe this may have been happening for several weeks although I did not make the connection until this weekend when the fan stopped working.

Power is reaching the contactor and when manually pushed in to make contact, the compressor and outside fan operate.

There appears to be no obvious burned out part. Transformer and Sequencer appear normal. Defrost control circuit card appears normal with no burned spots. There is no burned wire or other smell.

Any idea what might be wrong? My first thought is to suspect the Contactor as the system works when it is manually operated. However I am not sure that is all there is to the issue. Help please.

[pinkertonpv]

update to Heil heat pump not working

Update: Contactor mayu be good and defrost bd may be pbm.

Checked for 24 volts low side of contactor. 24 volts - good. Placed jumper wire from low voltage side of contactor to Y1 on low voltage Thermostat bus, , bypassing defrost bd, . After timed delay, compressor and fan came on. Doesn't that indicate a Defrost board pbm?