The old stat was 22 years old and each and every time that the heat would
automatically go on, the blue auxiliary light would light up. Should the
auxiliary heat always be on during calls for heat? Also, the room
temperature and set temperature were not in sink, being off about 5 degrees.

AKA is the same as emergency heat? I thought they were separate issues. My
new TH8320U has Heat on, Aux Heat on, and then a separate Emergency heat
indicator. Am I not understanding this correctly?

If aux heat is inefficient above 20 degrees should I simply set the aux heat
lockout at 20 degrees and above so that only the compressor would operate?

Maybe an intermittently stuck fan relay? If so I guess I should get a
professional to look at this and fix if necessary.

Re the heat pump, I do get the Heat On indicator and warm air comes into the
room, and sometimes it will switch to saying Aux Heat On, also with warm
air. Since Heat On brings heated air, does that mean that the compressor is
in fact working?

If the room temp is indicated at 70 and the set temp is 72 I will see the
Heat On indication and warm air. If I move the set temp higher even a few
degrees, the Aux Heat On indicates. Normal?

Last Q: Is it better or not to utilize the temp lockouts for compressor and
aux since I added the outside temp accessory to this new stat?

"


"Travis Jordan" wrote in message
...
~~~AAA~~~ wrote:
I have a Trane BWD724A100A1 heat pump system servicing my 600 s.f.
apartment. The original Weathertron stat appeared to be inop in that
whenever heat is called for the aux heat blue light indicates. I
purchased a Honeywell TH8320U and outside temp indicator that I
appeared to wire correctly to this stat that I just installed. Now,
a few ?s:


Aux heat (AKA emergency heat) comes from resistance-heating "heat
strips" which at outside temperatures above about 20 degrees are
terribly inefficient compared to a heat pump.

On occasion, after the new stat reaches the set temp during heat
cycle, the "heat on" indicator will turn off but the vents will
continue to blow out air, at decreasing temp. I put a thermometer in
the ceiling duct and at times this air continues to blow out for 20 -
30 mins going down to 63 F which of course lowers the room temp,
causing the heat to have to turn on again. Even if I remove the stat
from the wall plate the vents continue to push out this cold air for
at least several more minutes. As I said, this only happens
sometimes. Sometimes it appears to work correctly and the ducts shut
down shortly after the 'heat on' indicator turns off. How can I stop
this from happening?

Sounds like a stuck fan relay on the air handler.

I'll speculate that your heat pump component isn't working at all, that
the new thermostat did nothing to change this, and that you've got an
intermittently stuck fan relay. Time to call a service tech.