I have a 12 year old Trane XL-1400 heat pump. The outside unit is a TWY036A100A3. Up until recently it has worked well. Maintained twice a year. Maintenance history: changed a relay in the air handler a few years ago (aux heat), new TXV last year. More recently failed a fan thermostatic relay in the outside unit that controls the 2-speed fan. For a few hours, the compressor would come on along with the fan but the fan would turn off in a minute or so. Compressor would struggle and then turn off. I assume it may have repeated the cycle once the thermal interlock reset. No more than 3 hours of this before I noticed the failure. See my other thread for details.
About two weeks later, the crankcase heater failed (shorted to ground). Popped the 40 amp fuse in the outdoor box. Serviceman disconnected the crank heater from the 240 line for now.
My serviceman is still waiting on parts from the factory to fix the fan control. He wire around the faulty relay to keep my a/c running on one fan speed.
Looking for advice from those of you who work on these systems every day. Is the Trane nearing end of life? Is the couple hours strain on the compressor during the fan failure something to worry about? Should I fix the known problems including the crankcase heater and press on, or start to think about a full system replacement this fall?
OBTW, for what its worth... the outside unit is under a tall (10+ ft ) deck open on all three sides, so it's been protected from direct sun, rain and snow but has good airflow around it.