I have a recently installed new Trane system...

4TWX5024B1000A (XL15i) + 4TEE3F31B1000A
25,200 BTU's cooling
24,000 BTU's heating
13 EER, 15.25 SEER, 8.6 HSPF

And an existing Honeywell RTH7400D stat.

The system was professionally installed and seemed to get along great with the stat.

Lately the stat will get stuck on "wait" whenever it tries to call for heat. It rarely switches over to the "heat on" status. Sometimes it seems that the heat is on even when it is stuck on "wait" because the room temp will rise to 71 which is the target temp. But most of the time it remains on wait with the room temp continuously dropping into the 60's. I quite often hear a clicking sound either coming from the indoor unit or the stat. They are in proximity of each other. The clicking sound is usually heard in pairs about 15 to 20 seconds apart. I'm wondering if this is the "heat" turning on and off again...

This system controls one zone of our two zone house. As a result of the problem above certain rooms in the other zone end up getting super hot (I guess from the other unit over compensating) while rooms in the problem area remain cold.

I'm going with the assumption that the wiring between the new system and the stat was performed correctly although I am open to trouble shooting that part of the equation.

Here are the programming options as they are currently set in the stat.

0170 --> 7
0180 --> not prompted
0190 --> 0
0240 --> not prompted
0530 --> 1

These seem to be the settings that appear to be important to getting the stat to talk to the heat pump.

I'm wondering if these setting are correct for my scenario or if my stat needs to be replaced.

Any help would be much appreciated. Thanks.

Kevin

All of your questions should be asked of the contractor who installed your system and is responsible for its warranty but I will try and answer and provide you with info on the thermostat you have. Read your manual first so you have a better understanding of its operation then post back with your questions. One other item I will add is that set back thermostats do not work well with heat pumps due to electric or aux heat over ride.

BTW the WAIT sign is there when someone tries to force the unit to heat or cool before the time delay process is over. It is to protect the equipment from people playing Russian roulette with the thermostat as in raising or lowering the temp at to fast a speed. This will damage the equipment and that is why the thermostat outsmarts them and tells them that the equipment will wait for the time delay to run out before changing.

Manual

http://customer.honeywell.com/techli...it/69-1726.pdf

Thanks for your response. I'm not sure what a set back stat is.

The wait sign is being displayed even when no one is adjusting the temp. I actually set the schedule to have the same temp at all times to try remedy the problem. No luck.

If you read the manual the wait time is described in a couple of different locations. I see no fault where the wait time should be on for more than 5 minutes. You have another problem or it is the thermostat. If they sold and installed the thermostat call the contractor.

The thermostat was already installed with the previous system. Thanks for the rely.

Might be time for a new thermostat. Usually it is better to get a new thermostat when buying a new system.

I ended up getting a RTH7600. Wired per the instructions. The "Heat On" came on for about 10 seconds then switched over to "Wait". Could the compressor be switching on and off on its own and making the stat go into wait mode?

The wait sign is usually activated if someone tries to change a setting or something within a short period. Read the manual for your stat since that is what I am going to have to do.

Compressor minimum-off timer is active.
Wait up to five minutes for the cooling or

Heating system to turn on.

Set the unit and leave it alone for 10 to 15 minutes and see what it does. The WAIT is a system protection device built into the thermostat. Sometimes people play with the thermostat too much which can cause system damage so they built this in to prevent it.

Once again read your manual.

Starting on page 29 you have to do the proper set up or the thermostat will malfunction and possible cause the problem you are having.

NOTE try setting 530 in the set up to 0 instead of 1. Adaptive recovery does not work well with a heat pump. Try this for a few hours of leaving the thermostat alone then post back with results.

I had a guy come out and look it over and it turns out that the wiring from the stat to the air handler went bad. It was shorting out any time the stat called for the aux heat. He replaced the wiring and now it is working like a charm.

Bad wiring does have an effect on the operation of the thermostat and the unit itself. I am glad to know nothing got damaged other that the wire somehow.