Lennox heat pump w/ Honeywell CT3611R wiring

21:49 ______________________________________________________________________ I have a Lennox Elite 11 Series HP29 model heat pump with an mercury-contact thermostat. I replaced it with a digital programmable Honeywell CT3611R thermostat (designed for self-installation for heat pumps). Everthing appears fine, except heating. Only auxiliary heat turns on. The outdoor compressor does not turn on during heating. My outside temperature is 45 F (late April in Ohio). Temperature setting is 70F. (By the way, cooling works fine on warm days a week ago.) old Lennox wires: X, V, M, Y, F, R, E new CT3611R wires: C, R, Y, W2, G, O, E. I followed Honeywell’s wiring diagram for Lennox replacement. My old thermostat is around 17 years old while my heat pump compressor is only 4 years old. The compressor’s manual mentioned the following wires: C, R, Y1, W1, G, O, E. Did I miss something? Any help will be greatly appreciated. Replies: guting “Re(1):Lennox heat pump w/ Honeywell CT3611R w” , posted Wed 28 Apr 16:43 ______________________________________________________________________ My home is 100% electric. Heating is from the heat pump. (There are also a few independent space heaters in different rooms.) Xenos Webmaster “Re(1):Lennox heat pump w/ Honeywell CT3611R w” , posted Wed 28 Apr 16:42 ______________________________________________________________________ I am confused as to where we are. Can you please reply to the bottom message as there really mixed up. Thanks. Xenos. The best way to escape a problem is to solve it. guting “Re(1):Lennox heat pump w/ Honeywell CT3611R w” , posted Wed 28 Apr 10:32 ______________________________________________________________________ By the way, my compressor did not come on while auxiliary heat was on. I did hear a clear buzzing noise (like a transformer buzz). Honeywell technician told me that CT3611 did call the compressor for heat in that case. Something might be wrong with the compressor. However, I checked the A/C cooling of the heat pump, the compressor worked fine. The Elite 11 series H29 compressor was installed in Sept. 2000. guting “Re(1):Lennox heat pump w/ Honeywell CT3611R w” , posted Wed 28 Apr 09:27 ______________________________________________________________________ The old Lennox thermostat had only 7 terminals total, all listed above. It does not have stage 1 heating relay terminal. In CT3611R thermostat, there is a factory-installed jumper between Y (compressor) and W1 (stage 1 heating relay). Thanks. guting “Re(1):Lennox heat pump w/ Honeywell CT3611R w” , posted Wed 28 Apr 09:08 ______________________________________________________________________ Thanks for your reply. My wiring was exactly as you said which was also the same as in Honeywell’s wiring diagram. I wonder why the compressor does not come on for heating. I switched to A/C, the compressor works fine. But in the heating mode, only auxiliary heat comes on. Compressor is not moving at all. With the old Lennox thermostat, the system worked fine. By the way, during my testing, the indoor temperature was 68F, outdoor 45F. Heating setpoint 72F, cooling setpiont 65F. I always waited for several minutes before switch between heating and cooling. Someone told me that I should wait for the heating to kick in naturally instead of mannually increasing the setpoint temperature. Otherwise, the system thinks heat is needed right away and it will use the auxiliary heat source. Does this make any sense? Thanks in advance. Xenos Webmaster “Re(2):Lennox heat pump w/ Honeywell CT3611R w” , posted Wed 28 Apr 16:39 ______________________________________________________________________ Yes that would be corect, Is this a fosel fuel furnace? or electric. If electric this wouldn’t matter. Xenos. The best way to escape a problem is to solve it. Xenos Webmaster “Re(2):Lennox heat pump w/ Honeywell CT3611R w” , posted Wed 28 Apr 09:14 ______________________________________________________________________ You only listed a W2, I thought that thermostat had 2 Ws and one of them needed to be jumped to Y. did you list all the terminals you have? Does it operate in cooling? if not it’s not the thermostat. Xenos. The best way to escape a problem is to solve it. Xenos Webmaster “Re(1):Lennox heat pump w/ Honeywell CT3611R w” , posted Tue 27 Apr 22:07 ______________________________________________________________________ IF X, V, M, Y, F, R, E Are the old Lennox terminals then. X= Common Power = Honeywell C V= 24Vac Power = Honeywell – R M= Compressor = Honeywell – Y Y= Heat = Honeywell – W2 F= Fan = Honeywell – G R= Reversing Valve = Honeywell – O E= Emergency Heat = Honeywell – E Hope this helps. Xenos. The best way to escape a problem is to solve it. Xenos Webmaster “Re(2):Lennox heat pump w/ Honeywell CT3611R w” , posted Wed 28 Apr 09:13 ______________________________________________________________________ You only listed a W2, I thought that thermostat had 2 Ws and one of them needed to be jumped to Y. did you list all the terminals you have? Does it operate in cooling? if not it’s not the thermostat. Xenos. The best way to escape a problem is to solve it. guting “Re(3):Lennox heat pump w/ Honeywell CT3611R w” , posted Thu 29 Apr 08:08 ______________________________________________________________________ Problem solved!!! It appears that Aux. Ht. is turned on if user switches to heating from Off or Cooling. After the room temperature reaches the setpoint and the system kicks in automatically again (when room temperature drops), compressor heat will come on without Aux. Ht. A Lennox repair person told me that this behavior is normal. In summary, there is nothing unusually for wiring CT3611 to replace a Lennox thermostat for a regular heat pump. Just following Honeywell wiring diagram. Thanks for all the help I got. Cheers!

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