Very old heat pump- new t stat problems


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Old 03-11-15, 08:01 AM
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Very old heat pump- new t stat problems

Hello. I have a 1986 Lennox packaged heat pump with electric backup. We just bought the house, and the system has never worked right. Just replaced the thermostat with the intent of getting it working better, and now it's really messed up. Bought Honeywell RTH2410B t stat. Here's what I have as far as wiring on the old t stat. Red= R, Yellow - Y, M - orange, F - green, V - blue, X- brown. Have two unused wires also.

As for problems, I wired it per instructions, making a couple educated guesses, and heat worked all winter. However, bad frost buildup. Now, with warmer weather, no A\C. Fan runs, but compressor doesn't.

Any help you guys can provide would be great. I have everything open at the unit so I can chase wires, etc. Should be able to answer specific questions on the unit. Thanks!

Chris
 
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Old 03-11-15, 08:31 AM
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I am on a cell and cannot post my Houston204 pic of Lennox Alt wiring but you can probably google image it.

I can verify this tonight but..
Old -new
R-O
Y-Aux
M-Y
F-G
V-R
X-C

I see no emergency heat option on that new stat.
 
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Old 03-11-15, 06:37 PM
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Tape off the old X wire.
The old R is now O/B.
The old Y is now W/Aux.
The old V is now R.
The old F is now G.
The old M is now Y.

You must also set a couple of jumpers...
JP1 = HE
JP2 = O (should already be there)

You must also configure the stat...
Change function 6 from 0 to 1.
 
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Old 03-12-15, 04:02 AM
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My old thermostat, and looking at the existing board on the heat pump, has both R and V. What are my options since it says you can't use this thermostat if you have any two of the following wires... Im assuming the jumper changes take care of that? I'll try it, but I'm not sure how to change jumpers or where they are.
 

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Old 03-12-15, 04:41 AM
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On the back of the thermostat, I don't see any jumpers. Just a switch that says gas heat or heat pump.

As for functions, they skip from 5 to 20 with no 6. I set the wires as suggested and get fan running continuously without control, and no other functions.
 
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Old 03-12-15, 06:20 AM
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The old R is reversing valve. It is now O.

The old V is voltage. It is now R.

Pictures with lines pointing to the jumpers are on your manual.

If you don't feel comfortable following my recommended connections it might be a good idea to call a contractor.

If you print the link to your old stat that I posted it may help him.

I would get a different stat.
 
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Old 03-12-15, 07:00 AM
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I understand the new wiring conventions and the variations in Lennox wiring. That was very helpful. I have wired the thermostat just as you recommended. I just don't see any jumpers to be changed on the T-stat, and the only mention of jumpers in the manual is related to the jumper between R and Rc on the wiring block. In the T-stat controls, there simply is no function 6. It has functions 1, 5, 13, 14, 15, 20, 21, 40. All have been set as required by the manual. Any other ideas?
 
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Old 03-12-15, 08:03 AM
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They may have updated the stat since they published the manual I found.

The 2 jumpers are behind the stat 1/3 the way up from the bottom in the manual the I downloaded.
Looks like the are near the battery area.

Post the manual number that you have if it is available.
 
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Old 03-12-15, 08:08 AM
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I cannot download manuals from Honeywell's site to my cell. I can post a picture tonight but your stat should have come with the manual?

I never install lower than 5000 series Honeywell thermostats. This is the area that the feeling of a great quality product drops off.
 
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Old 03-12-15, 09:20 AM
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Thanks for all the help thus far. It's greatly appreciated. The manual I have is 69-2726ES-01. I think maybe they updated the stat since the manual you have, and replaced the jumpers with a switch changing the operation from "gas or oil" to "electric or heat pump". The function settings seem to be a little different as well, but I think I have everything set up correctly now according to the manual. However, I still have a continuously operating fan and nothing else works. No compressor, no condenser fan, no reversing valve. I am 100% sure the unit is still operational though, as it worked in heat mode before I started the T-stat rewiring. So, I am thinking either I need a different T-stat, or the wiring is still incorrect somehow.

Here's a pic of the T-stat connections inside the unit.

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Old 03-12-15, 09:28 AM
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And here is the link to the manual if it helps.

http://customer.honeywell.com/reques...form=69-2726ES
 
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Old 03-12-15, 05:06 PM
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Can you read the model number of the heat pump?
 
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Old 03-12-15, 05:47 PM
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Does the fan turn off when you disconnect the old V wire?

If you touched V to X it can pop a fuse or damage a transformer.
The fan often runs when 24 volts is lost.

Is the model number CHP15?

Lennox does not have great diagrams. Probably looks like 4 or 5 rectangles and 2 or 3 wires. If you by some miracle have a good diagram, posting it may be of assistance.
 
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Old 03-17-15, 06:30 AM
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Yeah the model number is CHP15. Still fighting this problem.

Just installed a new transformer as I had in fact killed the old one. I will try the V-wire disconnect and see if that kills the fan. Anything else I can try to get you more info? I can post a pic of the wiring diagram of the valve and compressor inside the panel if that would help.

Thanks again.

Chris
 
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Old 03-17-15, 07:18 AM
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I would add a 5 amp blade type automotive fuse between the new transformer and the air handler V terminal using a couple of spade connectors.

A pic of your diagram would be of assistance.
I am unable to get that old manual with the diagram.
 
 

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