Heat Pumps and Electric Heating - heat problem Trane XE 1000

Recently purchased a house with relativeley new Trane XE1000 exterior unit and old GE air handler (house 26 years old). AC fine. Heatpump OK when warmer. Recently have a problem: occasionally room temp air from vents until AUX heat kicks in. If I turn off the heatpump by going to Emergency Heat or turn down thermostat, heat pump will run normally next cycle.

When air not warm, large freon tube is cool to touch (not cold). Once, was hot (assume this was defrost cycle) and then turned cool and had the problem. Assume it is reversing valve? If so, what is etimate for parts and labor to fix. Do not have heating contractor and will use this as test case.

Also, any advantage in replacing air handler? had old one cleaned when we moved in.

Thanks

When the heat pump is in heating mode the fat copper line should be warm/hot and the skinny copper line should be cool/cold to the touch.

Personally I'd have it checked out by a pro. They may have used the old coil and only replaced the outdoor section which could cause you problems if not properly matched. You could be low on refrigerant, reversing valve could be going out and on and on and on.

On replaceing the airhandler, what kind of back-up heat does it utilize ?? If it's electric resistance then you may be fine if it's been maintained.

Could be any number of things these systems are fairly complicated and usually the only thing a HO can do is check for proper voltage and wiring connections, a tech can sort it out in a few minutes for a reasonable fee. If I were you I would be checking the wiring connections at the furnace and thermostat and if I had a multimeter and some electrical knowledge I would check for proper voltage at the contactor and thermostat. If you have been having trouble Quote "Heatpump OK when warmer" you may have a internal refrigerant problem that can only be diagnosed with proper equipment and certification. If you replace the furnace go with a matched coil for your condensor and a variable speed blower for maximum efficiency and comfort and of course the proper thermostat.

Thanks for both responses--one point of clarification is that 90% of the time (even when cold outside) heatpump does produce heat--only occasional mode of not producing heat which rectifies after turning off for 5-10 minutes.

will explore with contractor and look into a matched interior unit--am contemplating back up propane, so will explore.