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Brian HVAC Guy
Brian HVAC Guy, HVAC Technician
Category: HVAC
Satisfied Customers: 925
Experience:  I have been an HVAC/R mechanic/technician for 30+ years.
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Hello. I just installed a new Honeywell RTHL 2310/RTHL 221

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Hello. I just installed a new Honeywell RTHL 2310/RTHL 221 Series thermostat to operate my Trane heat pump. When I turned the AC on, the motor, fan, and blower operate, but it blows ambient temp air, not cool.

The thermostat is connected as (wiring to thermostat)
( C on old thermostat) Blue not used (because its a heat pump w/out auxiliary)
O to O
G to G
Y to Y. (Jumper between Y and W)
W to W
R to R

I remember that a technician needed to do something special because it is a trane, but I don't remember what. Can you please help? Thanks.

gotoman for ac : Russ here.. Be right back. Russ
gotoman for ac : Did you jumper RH to RC on thermostat. You have to do that for cooling. Russ
JACUSTOMER-8e2neyc4- :

I did not. the installation guide said to place a jump between y&w if using a heat pump without backup and so I did that. My house wiring has only an R. thermostat has a pre-existing jump between R & R C, which I left in place when i attached the R wire. I do not have an RH house wire.

JACUSTOMER-8e2neyc4- :

I realized that I should clarify. There is a jump between R&RC, and I left that in place, so there are two jumps on this thermostat;one that was already in place between R&RC and one that I put in between Y & W.

Hi, I'm Brian. I'm here to answer your HVAC question to your complete satisfaction! It appears Russ may have had to leave. I'd like to try to help. You say that the "motor fan and blower operate" Are you feeling warm or hot air coming off of your outdoor fan? Is your Trane system a package unit or split system (inside air handler/outside heat pump) or furnace with a coil above or below it and an outside heat pump? You say blue is unused because it is a heat pump w/o auxilliary heat, yet there is a white wire at W, are you sure there is no electric or gas/oil heat? If there were no auxiliary heat there should be only 4 wires necessary on your Trane, R,O,Y and G. If you could please answer all of the above questions I would appreciate it and will do my best to help you figure out this problem. Thanks, -Brian
Customer: replied 4 years ago.
Hi Brian. When the thermostat indicates that cool is operating, there is ambient temperature air coming from the floor vents. .... There is not a N excessive amount of air flow coming from the outdoor unit.

From your description *I believe* that is it is a split system. (It is a trance X R model 4TWR2036A1000AB.)

I am positive there are no gas or oil components, but from your description there is auxiliary heat, since there are more than those 4 wires, and they were all connected to the old thermostat. I apologize for my uncertainty, but my late husband used to handle all these kinds of things.

Thanks for your continuing help.
Thank you for your input. I'm sorry to hear about your husband. Yes you have a split system, that model number is XXXXX a Trane outdoor heat pump and since you have no gas or oil furnace then there will be a matching air handling unit inside somewhere and that air handler may have electric backup heat for your heat pump. That would be my suspicion and since you have Y jumped to W it's possible you are bringing on the electric backup heat along with the cooling and that is why you are getting what seems to be ambient indoor air coming out of your registers because the heat is off-setting the cooling. I would first remove the jumper from Y to W with no other wiring changes and see if you then get cool air when setting the unit to cool. That will tell us if you indeed have electric backup heat and if so, that thermostat will not support the backup heat option and you would have to upgrade to the next Honeywell model that does support backup heat to use that function. Let me know what you find and then if you would like, we can talk about the thermostat options a bit more. Thanks, -Brian
Customer: replied 4 years ago.
I just pulled the jump and I'm testing it now. I'll be back in a minute.Back from the test.... And there is a celebration here because there is cool air now coming from my ductwork! (Hopefully I'm not celebrating too soon but temperature in the house has gone down 1° so far, with about eight more to go:) Because it's over 90° here today, I am not going to mess with this right now. however, what are your recommendations on what kind of Honeywell thermostat I should install to run both heat and cool, now that I know that I do have auxiliary heat? Thanks in advance. Your help was really top notch.
Thank you for the kind words! I will look up the model of the Honeywell thermostat similar to the one you purchased but with the backup heat option and post it here. I will also include any pertinent info on installation. They are a little more complicated but not too bad and I'm sure you can do it with a little help.
Ok here is the next model up for a Honeywell heat pump thermostat that will also control your backup electric heat:

You would use the heat pump terminal designators on the wiring terminal strip and wire your system as follow:

Red to R/Rc (leave factory jumper in place)
Green to G
Yellow to Y
Orange to O/B
White to Aux and add jumper to E

If you can determine if the blue wire in your thermostat cable is connected to the B terminal of your Trane air handler then you can connect Blue to the C terminal of your thermostat. This will use the system power to power your thermostat and the batteries will only be used to backup your schedule/setpoints. If you can't or don't want to determine if the blue wire is hooked up to B on your Trane air handler then just tape it off and curl it and your thermostat will work on battery power alone and won't work if the batteries go dead so you will have to replace them more often.

This thermostat can operate a multitude of system types and you need to follow the instructions and enter the installer set up function and set these parameters for YOUR Trane system:

Function 1 parameter =5
All other functions/parameters should be fine at the factory default.

Thank you and good luck. If you have any other questions please post them here and I will gladly answer them for you!
Brian HVAC Guy, HVAC Technician
Category: HVAC
Satisfied Customers: 925
Experience: I have been an HVAC/R mechanic/technician for 30+ years.
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Customer: replied 3 years ago.
Hi Brian. I just received the thermostat you recommended. I have just one question how can I determine if the blue wire on my thermostat cable is connected to the blue terminal of my training air handler? I'd like to avoid operating only on battery power. Thanks. Barbara
Customer: replied 3 years ago.

Thank you. Asking again.... You said ". If you can't or don't want to determine if the blue wire is hooked up to B on your Trane air handler..."


How can I tell if the blue wire is hooked up in that way? (I do have a blue wire coming out of the house wiring. Is that it?)

Customer: replied 3 years ago.

I just started my upgraded week and so am asking again now, how can I tell if the blue wire is attached to the trane air handler? do you mean if a blue wire comes out of the house wiring?... if that's not what you mean, is there someplace on the unit itself I should look for blue wiring? Am I getting out of something that I could try myself? (I'm bold but I'm not foolish. ;)