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Discussion Starter · #1 ·
I just replaced my condenser fan motor because the bearings were shot in my old one. My unit is a Keeprite KSSD 19-36, probably around 25 years old. The old motor had 4 wires, red, black, brown and white. The new motor's wires are yellow, black, brown, and brown/white. After I installed the motor and turned the breaker on the condenser fan motor immediately came on, and the only way to turn it off is with the breaker. If I turn the AC on with my Nest thermostat the compressor will kick in and cold air will come out the vents. If I the air off with the Nest, the compressor will stop but the condenser fan will keep running until I turn it off at the breaker. I'm assuming I've wired something incorrectly but can't figure out what. I've attached the wiring diagram from the user manual as well as the wiring I currently have. Can someone please tell me where I went wrong.
Thank you
 

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Yah, sounds like you mis-wired it so it's getting power hot all the time and also used the wrong motor.

The new motor based on the wire colours is a single speed with an option to wire capacitor with two wires.

The old motor is a 2-speed.

You need a 2-speed motor of the correct hp (to maintain full functionality) and it has to be wired as per the diagram.

Never a good idea to go by wire colour alone, need to know which wire does what.

Old -> red is low speed, black is high speed (fed by a thermostat which gets power from T2 of contactor)), brown goes to the capacitor, white goes to power T1 of contactor


Are you in canada? I ask because this is a canadian unit and I know of a supplier that sells generic parts to the general public.

Anyhow, can you post clear pic of the old motor's label with all the info including schematic? The motor itself usually has a schematic on the label. (HP, rpm, rated amp draw very important to know in selecting another motor)

I know of one generic universal style motor that may work due to being multi horse power and having a separate lead that can be used for a lower speed. But the HP of your existing fan motor needs to be high enough so it will actually drop in speed using the lower hp wire.

If a universal multi-hp/2-speed won't work, you'll have to either try to find the oem motor (very hard as it's a old unit) or re-wire it as a single speed, take the fan thermostat out of the circuit.
 

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Your old motor was a 2 speed motor, your new motor is a single speed motor. Won't hurt anything, but lower efficiency a bit.



Non of the brown wires get connected to the speed control relay.


To use that single speed motor. Yellow wire should connect to T1 of the contactor, Black should connect to T2 of the contactor, and the brown wire to The F terminal of the capacitor(if its the right size for the motor). The brown with white stripe should just have a wire nut put on it, and then strapped somewhere safe that it doesn't move or touch anything else.
 

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Discussion Starter · #4 ·
I just hooked up Yellow to T1, Black to T2, Brown to F on the capacitor but it's the same result, only way to turn the condenser fan off is with the breaker.
(I kept the short red wire going from T1 to C on the capacitor, which I'm assuming should still be there.)

Yes, I am in Canada (Ontario). If you could provide me the link to get a new 2 speed motor that would be greatly appreciated.

I've attached a picture of the sticker on the old motor for reference.

Thank you for your time and your assistance.
 

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There's nothing wrong with using a 1-speed motor - impact on operation is minor. (more noise and minor changes to capacity and efficiency in milder weather)

The universal motor I was thinking of is up to like 1/3hp won't work well in your application with the existing one being only 1/6hp. The manufacturer already says to use the red low speed for 1/6hp to get full speed.

If you want to use a 2-speed motor, it will have to be cross referenced or be direct oem. Keeprite has changed hands more than once since that unit was produced so finding oem may be difficult if not impossible.

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I think you have it wired to the wrong side of the contactor.

There's the power incoming side and the switched side -> it has to be connected to the switched side.

Wise to change the capacitor when changing the motor btw - may be starting to fail by now and new motor can require a different value particularly if it's the multi-hp type.
 

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Discussion Starter · #6 ·
I think I have it on the switched side. I've included a photo so that it's easier to understand what's going on.
T1 has the yellow from the motor, the short red to the C on the capacitor, and a large red that goes to the compressor.
T2 has the black from the motor and a large orange that goes to the compressor.

I replaced the contactor a few years back because a mouse fried itself on in and it stopped working. I will look into replacing the capacitor though too.
 

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Well, the motor is getting its power from somewhere. I don't see anything bad in the pic that could do it.

To be clear, is the motor running at normal speed with no call for cooling?

Are you sure compressor coming on only with a call for cooling? It's in an insulated compartment so may be hard to hear with the cover on.
 

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Discussion Starter · #8 ·
Yes, it's very confusing. I turn the breaker off and the thermostat off to do the wiring. As soon as I turn the breaker back on the condenser fans starts up and it looks like it's going full speed. There is no air coming out of the vents.
Then I turn the thermostat to cool, and then the compressor kicks in the furnace blower fan and cool air will start coming out the vents.
I'm stumped.
 

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could take some probing with a multi-meter to figure out what's going on.

A long shot, just speculation - i do wonder if there's a short to ground affecting the fan circuit and it's getting fed 120v. can only happen with a single pole contactor.
 

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Sounds like one of the poles of the contactor is welded closed, and perhaps a short in the cap to ground. Use a multimeter to find out if either of the contactor poles is welded closed.
 
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Discussion Starter · #11 ·
So I tested the contactor, with the thermostat on I was getting 245 on the contactor. I then turned the thermostat off and I was still getting the 245 on there. So that sounds like the contactor is always open. I will get a new contactor and hopefully that will fix it. Should I still pursue a new 2 speed motor or is that not really necessary. I found one with the same specs except the amperage is slightly higher. The original was 1.5 and the replacement is 1.8, not sure if that is acceptable.
You guys have been an awesome help!
 

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Were you measuring on the L1 and L2 terminals, or the T1 and T2 terminals.


You want to measure from T1 to ground, and T2 to ground. With the thermostat turned to off.
 

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can you post a link?

I wouldn't worry too much about having a 2-speed fan. Most units even made now have a single speed and do fine. The lower speed is helpful in keeping the refrigerant pressure up in mild weather and allowing for full capacity and dehumidification. Real world difference probably not noticeable.

Whatever you do - don't replace this unit until the compressor fails or it springs a refrigerant leak. Nothing you buy will be as good - just walking I still see a lot of faded/slightly rusted old keeprites in my area which are in use, they're more common than others of the same vintage. They made them until the early 90s so even the newest are near 30 years. Nothing you buy now will last.

You're lucky to still have the documentation - it's unavailable online.
 

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Discussion Starter · #14 ·
I measured from T1 to ground and T2 to ground and both were 120, with the thermostat on and thermostat off.
The 240 was when I had the leads on T1 and T2.

Here's the link to the 2 speed replacement motor:
https://www.amresupply.com/part/12383822

I've been told the same thing about this unit. Hopefully it keeps going for lots more years, just a few replacement parts.
 

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That's the motor I was thinking of.

It won't work properly as a 2-speed due to being multi-horse power and being rated 1/6 to 1/3hp, what you need being the minimum of the range already.

You have a 1/6hp load and it would spin at full speed already with the red connected.
You would need a 1/4 or 1/3rd hp load to have it slow down using the red and run at full speed using the black.

Use the black and it won't run significantly faster, motor would just run inefficiently and possibly overheat, being at half load. Max speed is synchronous speed -> 1200 rpm I believe, close to 1125 it runs at with red.


See attached.

To get two speed operation, you need a "pure" single hp rated at 1/6 or near same amperage as what you have. Would likely need to be an oem style motor.
 

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That looks like a two pull contactor but I believe it may be a single. Replace it with a two pole.

Sent from my SM-G960U using Tapatalk
 

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And I believe you are right. It does say on the contactor that L2 to T2 is shunted.

Then you probably have a short to fround in the capacitor.
 

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I’m thinking he’s getting a backfeed through the compressor. Since the contactor only has one leg. You could isolate it by a two pole contactor. Or a separate capacitor and using the striped wire. Or could it be as simple as swapping the black and yellow wires on the contactor?
 
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