Thermostat upgrade problem with 9 wires

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  #1  
Old 02-23-19, 09:45 AM
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Thermostat upgrade problem with 9 wires

Want to upgrade to a programmable thermostat. It is a Honeywell RTH6500. Had old manual Honeywell with 9-wires:

B E G L O R W2 X Y

New one has:

K L Aux/E G O/B C Y R RC

Not sure of brand, but I have a heat pump/AC unit outside with air handler in crawl space. I called Honeywell to get advise and they provided me with a wiring schedule.

However, the fan outside seems to be running a lot and I am not seeing any sort of defrost time. It seems to be going straight to auxiliary heat. Obviously, something is amiss.

Honeywell told me to:
L=blank
G=G
Y=Y
R=R
X=C
O=O/B
B= Not used
E=Aux/E
W2=Aux/E

HELP! My bill was over $400 and want to get this corrected.




 
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  #2  
Old 02-23-19, 02:58 PM
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Some more information would be of assistance.
Do you still have the old thermostat? The model number may help us look it up.

Did you snap a picture of the old wire connections before removing that thermostat?

Did you configure your new thermostat for heat pump with Aux heat?
 
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Old 02-23-19, 03:51 PM
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https://customer.resideo.com/resourc...33-00130EF.pdf

Page 18 in the manual gives you instructions on setting your new thermostat for heat pump with aux heat.

Function 1 = 5
 
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Old 02-23-19, 04:13 PM
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Here's another thing to consider...... when in heat pump mode..... if the room temperature is 3 or more degrees below the thermostat set point..... the electric coils are turned on until the gap is closed. This is the single biggest reason for NOT using a programmable thermostat for heat on a heat pump system.
 
  #5  
Old 02-24-19, 02:47 PM
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There are several numbers, none that say model no.

LR1620
R10
T874R1285
8432X
8421
Q674L 1157

I did take pic and also marked the wires with the letter designations.
I also programmed the unit as you infpdicated.
 
  #6  
Old 02-24-19, 03:23 PM
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Do you plan on using setback temperatures/unoccupied modes with this thermostat?
 
  #7  
Old 02-24-19, 03:34 PM
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Q674L 1157
Is the sub-base model number. The model number for the stat is on it.
 
  #8  
Old 02-24-19, 06:26 PM
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I think the model number is after the T874 as I found this:
R1285 Obsolete. Honeywell logo; Rheem part no. 41-20796-15; used with Q674L1157.

Probably like was said - setback can backfire with a heat pump on a programmable thermostat.

Still should see what the wires actually connect to. If it was a Rheem then most used B and not O. Possibly thermostat was kept when compressor last swapped out.
 
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Old 02-24-19, 07:02 PM
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Yep, that looks like a Rheem / Ruud thermostat.

Are we sure that nothing was connected to the B terminal?

I would love to find out if the outdoor unit is a Rheem or a Ruud before another $400 electric bill comes up.
 
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Old 02-24-19, 07:43 PM
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Does the outdoor unit run when a heating demand is present?
Does the outdoor unit discharge cold air from the top when it is heating?
 
  #11  
Old 02-27-19, 04:35 AM
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Actually, the L is blank; meaning only 8-wires. The B was connected to B-terminal, but on upgrade Honeywell told me not to connect to anything. Not sure what was there, it was replaced as part of purchase agreement with an off-brand. Outdoor unit seems to run a great deal, especially when heat demanded. Air temperature isn't too bad, but cannot tell if cold air being expelled.[img]webkit-fake-url://b225f38d-5b94-4f0c-9308-a6cdfc0d24e3/imagejpeg[/img]
 
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Old 03-01-19, 11:07 PM
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Is the outdoor unit on the roof or some place that makes it difficult to take a picture of the unit tag?

Your link says "FAKE URL" in it.
Is that something you posted or is it a virus?

Was both the O terminal an B terminal in use with the old thermostat?
 
  #13  
Old 03-04-19, 02:25 AM
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Posted a photo of the old, but I guess I did not. Both the O and B were wired and in use to the old thermostat.
 
  #14  
Old 03-04-19, 07:04 PM
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If you post the make and model number of the outdoor unit we may be able to save you a couple of hundred dollars on your next light bill.

You can pay someone to get this information for you and still come out cheaper than running heating and cooling simultaneously.
 
  #15  
Old 03-04-19, 07:09 PM
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There is a high probability that you need to use the B wire at the O/B terminal and need to change the setting of the OB terminal.

If this is the case you are running cooling and heating at the same time.

If the condenser is in a location that you are unable to access like a roof, you should call an AC company out to get the required information from the condenser and air handler to properly set up your thermostat.

If you can access the outdoor unit, type the make and model number in your post.
 
  #16  
Old 03-11-19, 07:30 AM
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Brand: Weather King. Model: 13PJA24A01 Serial No: 7329 M2206 05175Volts: 208/2320. Phase 1. Hertz: 60. Compressor: R.L.A. 9.9/9.9 L.R.A. 54. Outdoor Fan Motor: F.L.A. 0.8. HP (Watts): 1/6
 
  #17  
Old 03-12-19, 01:16 PM
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Weather King

Appears to be a Rheem unit, at least that comes up when I put the model number in.

 
  #18  
Old 03-12-19, 02:22 PM
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So should have used B wire from old and not the O. So a/c running all the time when trying to heat - had to use aux coils.
 
  #19  
Old 03-12-19, 02:59 PM
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So I should switch and connect the B and leave the O unconnected?
 
  #20  
Old 03-12-19, 03:32 PM
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And change the O/B setting to B in the thermostat. Page 18 function 2 - https://customer.resideo.com/resourc...33-00130EF.pdf

Should still trace the O wire to see where it goes. If you have zones (multiple thermostats) you might have issues when you need a/c.
 
  #21  
Old 03-12-19, 05:59 PM
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Presume separate wire to the up unit.
 
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