Sanyo: Abnormality in external ROM of outdoor unit

Model CH5524VKA2 Goodman compressor 25 years old Seems to have a problem going in or coming out of defrost mode intermittently. I shut it down at the thermostat and restart it 5 minutes later and it's ok for a week or more.I thought I'd try to replace the solenoid. Is it just a matter of disconnecting the wires, removing a nut and pulling it out?

Hi everyone, I wrote in last winter as it was our first winter in a home with an air source heat pump and electrical aux backup. Located in Canada. We operate under time of use electricity pricing where prices are lowest between 7pm and 7am. When we moved in, the previous owners had a 3 degree Celsius setback overnight. This resulted in a huge spike of hydro at approx 5am as it moved to reach the warmer set point for wake up. The cost savings (as the heat was basically off all night) were close to nil. Any savings were lost when the aux heat kicked in at 5am. I did some research at the time and most recommendations where to NOT setback a heatpump. Made sense. So I changed it to remain constant temp all day. House is occupied all day. So far this winter, the costs do appear higher this way. Heatpump with occasional aux use over night seems to be more expensive. Costs between 15 and 70 cents an hour overnight. Say between 11pm and 5am. From what I remember, when I had the setback programmed, it was pennies an hour til the 5am mark when it would cost $1-$1.50 for the 5-7am warmup period. I think I’m going to try a simple 1 degree setback overnight and see how it compares. Tough to do perfect comparisons given fluctuating temps and solar heat. We can get cold days at -15 Celsius with a lot of sun and the heat doesn’t kick on all day. We’re southern facing with full windows across the length of the home. Heatpump runs a lot during the day and night as far as I can tell. It’s been between -5 and +5 C most days. Realize we’re at the limit of exterior temperature where a heatpump can deliver adequate heat, but is having the outside compressor running all day normal? Or would having the aux kick in earlier be better from an compressor lifespan perspective? Are these units designed to run 16-18 hours a day? I’ll let you know what I learn.