Lennox HP inside/outside Wiring

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Old 02-20-10, 07:59 PM
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Lennox HP inside/outside Wiring

So, I am trying to understand the wiring of this Lennox HP.

On the back of the Honeywell Chronotherm III:

R has red wire (24VAC Power)
C has black wire (???)
O has orange wire (Reversing Valve for Heat???)
Y1 is jumped to W1 and has Yellow wire (Compressor/Aux Heat)
E has brown wire (Emergency Heat)
W2 has White wire (Second Stage Heat)
G has green wire (Inside Fan Blower)
B is not connected (???)
L is not connected (Service Light)
P is not connected (???)
 
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Old 02-20-10, 08:27 PM
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R has red wire (24VAC Power)
C has black wire (24VAC common)
O has orange wire (Reversing Valve for Cooling)
Y1 is jumped to W1 and has Yellow wire (Compressor energized for cooling "Y" and Heating "W')
E has brown wire (Emergency Heat)
W2 has White wire (Second Stage Heat)
G has green wire (Inside Fan Blower)
B is not connected (Reversing Valve for Heating) (Lennox energizes reversing valve for cooling)
L is not connected (Service Light)
P is not connected (No idea The T86xx xxxx model number may bring this up)
 
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Old 02-21-10, 06:54 AM
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Thank you for the additional info, Houston204.

Can you tell me the markers/colors and what they do for the HP26-411-1P and the CB19-31-2P with ECB19-10-1P.

Also, what do the individual parts of the model numbers mean?

Thanks.
 
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Old 02-21-10, 10:09 AM
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What's a marker/color ?

I'm not a Lennox Tech. I do have a Lennox user name and password since we do sell some. Yuri may be able to anwer the model number breakdown. I didn't see it in the manual.

Have a look...

http://tech.lennoxintl.com/PDFs/504711b.pdf

http://tech.lennoxintl.com/PDFs/502701.pdf

http://tech.lennoxintl.com/PDFs/503019.pdf
 
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Old 02-21-10, 12:01 PM
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Thank you very much for those tech pages. I had seen the HP26 one, but not the other 2.

I do have a question though about W1, W2, W3.

The wall panel that the face of the Honeywell Chronotherm III T-stat clips onto has Y1 and W1 jumpered together with a metal "U" - yellow wire. Y1 engages the compressor and W1 engages the Aux. Heat, thus at the same time (jumpered). Then I guess the Aux. Heat drops out after the heat pump warms up? It's not continuously running Aux heat (W1) at the same time as the HP, is it?!

The T-stat also has W2 with a white wire connected, which engages Aux Heat (2nd stage). Would this be for when the demand on the HP is more then 2 degrees?

The T-stat also has E with a brown wire connected, which engages Emer. Heat W2 (2nd stage) and if installed W3 (3rd stage). I don't think it has 3 heat strips. Do I understand this right?
 
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Old 02-21-10, 12:25 PM
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Your stat W1 does not connect to the electric heat strip terminal at all. It is jumpered to the compressor Y terminal to run the compressor on demand for stage 1 heat. Since the O terminal will not get energized with a stage 1 heat demand, you will run in heat mode.

W2 will energize the electric heat strips with a demand greater than 2 degrees (along with the compressor) as you have stated.

The E terminal energizes the heat strip without energizing the compressor terminal. (Y, W)

Since you have a 10KW strip (ECB19-10-1P) you do not have 3 elements.
 
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Old 02-21-10, 02:27 PM
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Okay, now I'm understanding the wiring much more.

So, is there 1 or 2 heat strips??

If there is only 1 heat strip, then does it double as aux or emer. heat?

If there are 2 heat strips, does emer. heat energize both?

Also, I noticed a difference in the HP26 tech note from above and the one that I had already HP26 earlier/later. I have the earlier/older HP-411-1P that has the reversing valve on the left side of the compressor and the internal setup is more complex looking then the later/newer version.

Again, thanks for all your help!
 
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Old 02-21-10, 03:13 PM
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You have two 5kw strips that should both energize when the air handler W1 (stat W2), or E is energized.

E should connect the the same W1 terminal at the air handler.

It is possible that someone has seperated the 2 strips after installation but I doubt it.
 
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Old 02-21-10, 06:27 PM
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The reason why I ask is that when either the HP is in Defrost Cycle or in Emer. Heat the warm (if you can even call it that) air from the heat strips that comes out of the first vent above the air handler is barely luke warm and they struggle to keep the inside temp above 70 deg. F. The outside temp was in the upper teens to lower 20's. I ended up putting the unit back in HP mode as the air coming out was warmer then from the heat strips! Could it be that the heat strips are not even working?!

The HP Defrost Cycle is currently broken as it has frozen up like a huge ice cube twice in 2 weeks. I have been able to run the system in A/C mode to simulate the Defrost Cycle for 15 mins to melt the ice off the HP coils. The first time it happened it was rainy outside and the second time it was humid and foggy, both times the temp was between 30 and 40 deg. F, which are ideal conditions for ice to build up on the HP coils.

As I said earlier this is the earlier HP26-411-1P model that has the Reversing Valve on the left side of the compressor and the HP set up is more complicated looking then the same newer model.

The Defrost Circuit is make up of the Defrost Terminating Thermostat, the Defrost Board, and the Defrost Relay. I took a look inside and the Defrost Board doesn't look burned, but it does look aged/weathered. The Defrost Terminating Thermostat was securely clipped on, but it looks like something white is handing from it, like a piece of plastic. ??? The next time I open it up I'll tap on the Defrost Relay a couple of times and see if I can see stuck or broken fingers inside the clear case.
 
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Old 02-21-10, 07:08 PM
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Do you have an amp meter?

A 5kw strip at 240VAC will pull 20.83 amps.
5000/240 = 20.8333 or 5000/230 = 21.73

I can see why a heat pump with strips would be warmer than strips alone.

That clear relay should appear burned if it is failing. My money is on the board.

You might jumper the defrost stat to to eliminate it as your problem.

From your posted manual...
Early Model HP26−1 (208/230V)

6− During heating operation, when outdoor coil drops below
35 plus or minus 4 degrees F, the defrost thermostat (S6) closes. When
defrost thermostat closes, defrost timer (CMC1) begins
timing. If defrost thermostat remains closed at the end
of 30, 60 or 90 minutes, defrost relay energizes and defrost
begins.
7− When defrost relay energizes, reversing valve (K4−1)
and indoor electric heat (K4−3) relay are energized.
K4−2 de−energizes outdoor fan (B4).
8− Defrost continues until 14 + 1 minutes have elapsed or
until the defrost thermostat opens. When defrost thermostat
opens to terminate defrost, the defrost timer
loses power and resets. Defrost timing is stopped until
the next call for defrost (when defrost thermostat
closes).
9− After each thermostat demand is satisfied time delay
locks out the circuit to compressor contactor coil and
defrost control for 5 + 2 minutes. At the end of the timed
period, the time delay allows the compressor contactor
and defrost control to be energized upon demand as in
step 2.
 
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Old 02-21-10, 07:55 PM
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I just have a couple of DDM's. But I have been thinking about buying an AMP 'clamp' meter. Have any suggestions, place to buy, or prices? I don't need the best, but i don't want the worst either, just something in the middle.

Would it hurt if I left the T-stat in place, connected and just jumper the 24vac from the terminal directly to the Defrost Board where the other leg of the T-stat connects? Or should I disconnect it and just do the jumper of 24vac directly to the Defrost board?

Defrost Board - Does R1 look burnt to you?

Defrost Relay - Looked clear when I saw it, but will check it again.

Defrost Terminating T-stat - See the white broken white plastic piece in between the T-stat and freon tube? What is that and is it effecting the T-stat?

Also, what is this and what does it do?! Looks like it is set on about 43 deg. F.
 

Last edited by AWEstun; 02-21-10 at 08:14 PM.
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Old 02-21-10, 08:11 PM
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Will it initiate defrost when you jumper the 2 test terminals displayed on your defrost control?
 
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Old 02-21-10, 08:25 PM
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I haven't been back out there to check things out again since a couple of days ago when I took those pictures.

I've been researching and gathering as much knowledge about the system as I can.

What is the procedure to jumper test the Defrost Board? I would assume the system needs to be running in HP mode and you just use the tip of a screw driver to momentarily short those two test pins together?

Then what is supposed to happen? I would assume the Defrost Relay clicks and simultaneously the fan cuts out, the Reversing Valve reverses into A/C mode, and the inside Aux Heat Strip(s) energize all while the compressor is running?

If this does happen for how long will it run of the 14 +/-1 minutes that it would normally run?

If I remember from the Defrost Cycle working in the past and having read the tech notes, the system shuts down after completing it's defrost-A/C cycle and wont restart in normal HP mode until the TOC clears it's 5 +/-1 minutes, right?

Would I be able to test the Defrost Board to see if it is giving a 24VAC signal to the Defrost Relay to engage? That would be 'out' (24VAC to relay) and common on the terminal line, right?
 
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Old 02-21-10, 08:27 PM
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Yes, use a screwdriver tip.
I'd expect it to go back to nomal operation on it's own very quickly, but I would would certainly watch it run untill this occurs.




I've always used Fieldpiece untill last year. I like Extech, it has an impressive capacitance range.

$80 at Frys for this Extech MA220... looks like they have a location in Austin, AWEstun.

FRYS.com*|*EXTECH MA220


http://www.extech.com/instruments/re...s/MA220_UM.pdf

I'm using an Extech EX612 now.
 
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Old 02-21-10, 08:52 PM
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Okay, so if I jumper test the Defrost Board and it energizes into Defrost Cycle, that will tell me that both the Defrost Board and Defrost Relay are good and that the Defrost Terminating T-stat is bad, right?

If I jumper the test on the Defrost Board and it does not energize into Defrost Cycle, that will tell me that either the Defrost board or the Defrost Relay is bad, right? In this case then I could put the DMM on the 'out' and common and jumper test to see if there is 24VAC on the 'out' for the Defrost Relay. If not then the Defrost Board is bad. If there is 24VAC on the 'out', then the Defrost Relay is bad. Right?

Did you see the picture of the Defrost Terminating T-stat with that white weird looking plastic between the T-stat and freon tube? What could that be???

Also, did you see how R1 (resistor 1) is burned looking in the middle on the Defrost board (left side and middle)?
 

Last edited by AWEstun; 02-21-10 at 09:46 PM.
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Old 02-21-10, 10:35 PM
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It would at least prove the relay isn't the cuprit.

If you jumper test and it does not initiate defrost, it would indicate the sensor isn't the culprit. (but it does look ugly)
Ohming it out with a freezing temp at the sensor would be a good test.

Would you say that resistor is orange, orange, brown, gold starting from the side closest to the stripes?

Resistor Calculator
 
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Old 02-21-10, 11:03 PM
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Wait, I read on the tech notes that the 24VAC goes to the Defrost Terminating T-stat first, then if it is cold enough 35 +/-5 deg F then it closes and lets the 24VAC through it to the Defrost Board. Then after the set 30/60/90 accumulated time the on-board relay sends the 24VAC 'out' to the Defrost Relay and it closes, and simultaneously cuts the fan off, energizing the reversing valve for A/C mode, and energizing the aux. heat strip(s) for 14 +/-1 minutes or until the Defrost Terminating T-stat opens (warmer then 30 +/-5 deg. F) and breaks the 24VAC feed to the Defrost Board.

So, if I jumper 'test' on the Defrost Board and don't get any kind of response, then I'd bypass the T-stat and jumper the 24VAC directly from the term to the 24VAC on the Defrost Board. Then jumper 'test' again and see if there is a response. If no response then most likely the Defrost Board is bad, but I could verify that by using a DMM to check if there is an 'out' of 24VAC even leaving the Defrost Board for the Defrost Relay. If not, then the defrost board is definitely bad.

As for that R1 resistor that looks burnt on the Defrost Board, I can't even make out the color bands. I still have my resistor slide chart from AC/DC class (college course) in HS! I'm 95% sure it is the Defrost Board that is bad.

I'm tempted to just go ahead and order the Defrost Board and the Defrost Terminating T-stat, as that will be just over $100 and get me free shipping. I'm almost willing to take a chance that it is not the Defrost Relay that is bad.

I just remembered that there is a smaller black cut wire hanging down from around the top of the compressor. Did someone cut the compressor thermal overload???
 
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Old 02-21-10, 11:24 PM
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I would actually remove the mounting screw and examine the relay for obvious burned points.

I'm also very confident it is the defrost timer.
The sensor might also be a good idea though.
 
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Old 02-22-10, 05:35 AM
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The outside weather will be up to 55 deg F today and dry, so I might go remove the T-stat. Put it in a ziploc bag and freeze it for a couple of hours and then check for continuity across it. If it is bad, can I just jumper the 24VAC from the terminal directly to the Defrost Board and leave it like that so the HP goes into defrost mode every 90 minutes of accumulated run time? Tuesday it's likey to snow some in central Texas and be down to 30 Tuesday night and a couple deg. colder Wed night. So, if the T-stat is bad and I just jumper it and leave it that way, then at least the HP would run the Defrost Cycle every 90 minutes of accumulated run time.

Also, do you know what the POTS (big black knob) with the 43 deg F temp setting is that is in front of the compressor? It seems to be some kind of temperature/thermostat as it has a probe wire sensor stuck into the hollow bottom of the HP frame. What does this control? Something tells me that it energizes the aux heat strips when when temp is below 43 deg. F outside, when the HP is first turned on???
 

Last edited by AWEstun; 02-22-10 at 05:52 AM.
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Old 02-22-10, 10:35 PM
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I'd say, at 43 degrees and colder, any time you call for stage 2 heat you will energize both strips.

 
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Old 02-24-10, 12:36 PM
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same basic model heat pump

Originally Posted by Houston204 View Post
What's a marker/color ?

I'm not a Lennox Tech. I do have a Lennox user name and password since we do sell some. Yuri may be able to anwer the model number breakdown. I didn't see it in the manual.

Have a look...

http://tech.lennoxintl.com/PDFs/504711b.pdf

http://tech.lennoxintl.com/PDFs/502701.pdf

http://tech.lennoxintl.com/PDFs/503019.pdf
Houston204,

My daughter has the older model Lennox, the only difference to the unit we`re talking about is its model #HP26-311-1P, and a couple of minor differences; fixed thermistor RTS wired back to the thermostat, and defrost control board that has the connections "C", "Out", "R" and "Hold". It also has a time delay board just to the right of it wired from the "Y" thermostat input lead and from "Out" to the "Hold" terminal on the defrost control board. The heat pump has no adjustable thermostat to energize the electric heat strips. I just joined this site, so I don`t yet know how to include photos (I have ten). If you let me know how to add photos from my computer, I can upload them to you.
 
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