My Trane Heat Pump runs continuously. It reaches the set temp on the thermostat but never stops blowing air. Also, the air is warm only when aux is on, as soon as aux is off, air is cooler. Unit is only 5 months old & has been doing this since it was installed. HVAC company has come out 3 times & done nothing about it.
Any advice would be greatly appreciated.

 

Possible dip switch issue...
What is the model number of the outdoor unit?
What is the model number of the indoor unit?

Possible return air leakage...
What is the temperature of the air at the air intake filter grill?
What is the air temperature entering the indoor unit 6 inches before the unit?

 

You've set the temperature on the thermostat.
Your saying the blower keeps running past the set temperature.
You must note if it's just the inside blower or blower and outside condenser.
Have you waited to see what happens when the room temp goes one degree over the set temp ?
Thermostats operate in 1/10's of a degree. It is very possible it won't stop at exactly the set temp.
That is not a problem.

Your heat pump is primarily the compressor driven method.
The aux is only for when the heat pump can't keep up.

You need to be aware of what your system is doing. If it switches into aux it would indicate that the room temperature is 3 or more degrees below the set temperature OR the heat pump is running with no temp increase noticed. You need to see exactly what it's doing so you can tell your installer. Outside temps should also be noted when checking for problems.

It sounds like the heat pump is not working as well as it should be. Unless you are in a real cold area or make large changes at the thermostat.... you should hardly ever see aux. The banging typically means the condenser is short cycling. That can damage a compressor but is not caused by the compressor.

Your system will use the aux heat when the heat pump is defrosting.

Houston will check further as he is the Trane expert.

 

Model# TEM4A0B30S31SC

Model# 4TWR4030G1000A

I don't think its an air leakage because the unit was running nonstop like this since the first day it was installed. After 3 months, the outdoor unit started making a loud banging noise. The HVAC tech came out & said it was wired incorrectly...after he left, it worked correctly for a few weeks but then started having issues again. The unit does not shut off when the set temp is reached. Could it be a damaged compressor from the nonstop running? and a faulty blower relay timer switch?
When I turn the power off at the breaker for 30 mins & then turn it back on, the unit will run properly for a few days & then go back to blowing nonstop.

 

What causes a condenser to short cycle?

Here's an example of what's happening at this moment. It is 60 degrees outside, my thermostat is set at 65, it has reached 65 over an hour ago yet the air is still blowing & its blowing cold air. The fan on the outside unit (condenser) is spinning. The only way to get the system to stop blowing air is to manually turn it off at the thermostat or shut the power off at the breaker.
When I turn the system back on, aux turns on & warm air blows out...as soon as aux turns off, the air coming out of the vents is cold & it will run forever this way unless I turn it off again manually. The outside temp doesn't make a difference...it will do this whether its 40 degrees outside or 70. It just runs nonstop until the end of time lol.

 

To be specific.... you have set the thermostat to 65f. Does the display actually show over 66F ?
If it does... that would indicate a thermostat problem.

 

No, it does not show over 65.