I have a Rudd heat pump system (circa '98). Lately it has developed a problem where when in cooling mode, the Aux light comes on and the unit blows hot air (it is 95F outside and the unit is set to 75F inside). If I turn the system off (breaker on the air handler) the problem goes away for awhile. Sometimes it fixes it for weeks, sometimes only for 5 minutes and then the cycle repeats.

Last cooling season I had this problem and called a tech. He said the wires in the thermostat needed to be re-seated (which he did) and the problem went away (but now problem is back this summer). I re-seated the wires (lossened and then tightened screws) but this has not solved the problem this time.

Any suggestions before I call the tech again?

 

The stat is what's kicking the aux on. It will need replaced but in the mean time you can just unhook the aux heating wire from the stat till you get a new one.

 

I've got a trane heat pump and it is behaving in the same manner. Last night I unhooked the auxillary heat wire, but I noticed today that it was blowing hot again. It wasn't the heat strips, it seems that the a/c went into heat mode. The coils inside were very warm to the touch. I went to a window that allowed me to see the outside unit and saw that the fan on top wasn't turning, and I could hear the compressor running. I don't know exactly how the system operates (obviously) and the more I dig the more modes and features I uncover. Any idea? again: in cooling mode, auxillary lamp illuminates, 1st stage heat strips come on, and the house heats up. I disconnected the "w" terminal in the thermostat and now the house still heats instead of cools at times, however, the heat strips don't come on. Also, outside unit was running without turning the fan. The family is getting hot under the collar....

 

Sounds like the unit goes into a defrost mode on you. Check defrost boardor controls in outside unit.

ED

 

hole man If your outside condensor compressor is running without the condensor fan on in AC mode you probably have a bad fan motor or capacitor just go ahead and change out both pieces. When the fan motor stops and the compressor continues to run the system pressures will rise to almost unreal numbers, your system will fail very quickly if this problem is not soon corrected. confirm by checking temp on outside coils when the problem occurs CAUTION they will probably fry your hand if you stick it on there!

 

Holekamp,

Interesting. That is similar to an issue I'm having. Essentially, the heat pump is always on (even the "off/auto" switch on the t'stat doesn't do anything). It will either cool or heat (the heat is coming from the heat pump and not the furnace) depending on whether the set "cooling" temperature is higher or lower than the current indoor temperature. It seems to completely ignore the second temperature setting (the one to tell it when to start heating).

You may want to try playing with the temperature settings to see if you can "force" it into cooling or heating mode. If this works, then you can at least force it to stay in the cooling mode until you can fix it.

However, until you can get your outdoor fan working, you may just want to keep the whole system off.

Good luck.

Andrew
P.S. My own solution is to replace the thermostat. Even if it doesn't fix this problem, I wanted to replace it anyways (it is an old mecury switch).

 

Many units will go into a defrost mod. You will have heat inside and the outside fan dont run. Id start for sure with the defrost board.
On that new tstat a progammable one is not to good for a heat pump on heat. Cause when it tries to get the heat back up it kicks on the strip heats so it cost you what you saved in fuel.

ED