# How to troubleshoot this ac?



## farmerjohn1324 (Feb 22, 2018)

I swear this thing just stopped working a few days ago.


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## billshack (Feb 23, 2018)

1) check for electric power. blown fuses.
2) check that t'sat is calling for cold.
3)check that fan can turn on both condenser and air unit. filters ect. 
4) look for anything that is out of the ordinary.
5) hook up pressure gauges  just to see if there is any refrigerate .


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## farmerjohn1324 (Feb 24, 2018)

billshack said:


> 1) check for electric power. blown fuses.
> 2) check that t'sat is calling for cold.
> 3)check that fan can turn on both condenser and air unit. filters ect.
> 4) look for anything that is out of the ordinary.
> 5) hook up pressure gauges  just to see if there is any refrigerate .



1. There are no electrical problems or tripped breakers that I can see.

2. The thermostat is calling for cold.

3. The fan turns on outside. I'm not sure what to be listening for on the inside unit. I can hear the furnace turn on when I set it to heat. But I never feel any air coming out of the registers.

I think I hear the inside fan trying to turn on when I set fan to "on" rather than "auto."

So should I open up the inside air handler? And look for what?


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## farmerjohn1324 (Feb 24, 2018)

I just changed the filter maybe 10 days ago. Could that be related to the problem? I changed it to the same size and brand that it previously had.

There's a brown stain on this new filter already and it's very wet. When I took it out, I thought the fan came on, but now it's not.


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## farmerjohn1324 (Feb 24, 2018)

Update: been doing some reading. I think the evaporator coils are iced. Maybe due to a blockage by the new filter?

But this is a new filter that was replacing a dirty one.

Should I go buy a new filter? How do I make sure this won't happen again?


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## tuffy (Feb 24, 2018)

1thing that causes that is low Freon, also poor air flow from dirty coils. Fan not working.


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## farmerjohn1324 (Feb 24, 2018)

tuffy said:


> 1thing that causes that is low Freon, also poor air flow from dirty coils.



Since the problem started around the same time I changed the filter, I think poor air flow is more likely. Especially since I think I heard the evaporator fan try to come on as soon as I took this filter out. All the registers in the house are open.

I just don't understand why putting a new filter in would cause this problem. And if I go get another, the problem may just happen again. Should the system work with NO filter in it? Should I try to get it working with no filter before I go out and get a new one?


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## kok328 (Feb 24, 2018)

the new filter doesn't have anything to do with your problem.
the problem was happening prior to the filter change cause the old filter was soaked by the melting evaporator coil ice.
shut the unit down until things thaw out, then try to run just the blower without heat or A/C.  I suspect your blower system is bad or going bad.  notice the speed of the blower in both heat and A/C mode as each setting will run at different speeds.  could be your cooling winding is bad but heat windings are Ok.
let us know what you find.


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## farmerjohn1324 (Feb 24, 2018)

kok328 said:


> the new filter doesn't have anything to do with your problem.
> the problem was happening prior to the filter change cause the old filter was soaked by the melting evaporator coil ice.
> shut the unit down until things thaw out, then try to run just the blower without heat or A/C.  I suspect your blower system is bad or going bad.  notice the speed of the blower in both heat and A/C mode as each setting will run at different speeds.  could be your cooling winding is bad but heat windings are Ok.
> let us know what you find.



How do you know the old filter was soaked? The filter in the picture is the new one from 10 days ago.

Should I take any of the panels off? Or just listen through the metal?


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## kok328 (Feb 26, 2018)

Because you said it was soaked. 
Panels on or off as long as you can get an idea of the fan speed.


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## farmerjohn1324 (Feb 26, 2018)

kok328 said:


> Because you said it was soaked.
> Panels on or off as long as you can get an idea of the fan speed.



The new filter was soaked. I don't remember the old one being wet, just dirty.

So the problem might be the filter. Just wondering exactly why.


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## kok328 (Feb 28, 2018)

I still think the problem is with the blower motor. At least from what you have described. I cant see hear or feel the unit so youll have to be my eyes and ears and I can only go based on what your saying. 
Basically I think your not moving enough air across the colis to keep them from freezing and thawing and soaking the filter.


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## slownsteady (Mar 3, 2018)

The machine worked fine before you changed the filter
The machine stopped working when you replaced the filter

Maybe you didn't put the filter in right or you didn't close the unit up correctly.


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## farmerjohn1324 (Mar 4, 2018)

I left it running for 8 days, set on 72 degree "Cool" and the fan set on "Auto" with no filter in.

When I got here, the house was 72 degrees, but not sure it was running because that's about the same temperature it is outside.

The ice seems to have melted from the evaporator coils, however.

I turned the fan to "On" and I think it hums, but doesn't turn on. This is what it sounds like.

https://www.dropbox.com/s/940rwxvzt65zqqu/0304181820.mp4?dl=0


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## kok328 (Mar 5, 2018)

farmerjohn1324 said:


> I left it running for 8 days, set on 72 degree "Cool" and the fan set on "Auto" with no filter in.
> 
> When I got here, the house was 72 degrees, but not sure it was running because that's about the same temperature it is outside.
> 
> ...



Bingo!!  That's what I was referring to.  Either the motor or capacitor or both are bad as long as your getting proper voltage to the windings.  Do you have any meters to test these components?


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## farmerjohn1324 (Mar 8, 2018)

kok328 said:


> Bingo!!  That's what I was referring to.  Either the motor or capacitor or both are bad as long as your getting proper voltage to the windings.  Do you have any meters to test these components?



No. What should I buy?

And I still find it interesting that this problem started the same time I changed the filter. Guess it's just a coincidence.


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## nealtw (Mar 8, 2018)

farmerjohn1324 said:


> No. What should I buy?
> 
> And I still find it interesting that this problem started the same time I changed the filter. Guess it's just a coincidence.


 
coincidence    coin-cadence, change that to dollar-cadence:hide:


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## farmerjohn1324 (Mar 8, 2018)

kok328 said:


> Bingo!!  That's what I was referring to.  Either the motor or capacitor or both are bad as long as your getting proper voltage to the windings.  Do you have any meters to test these components?



https://youtu.be/flbUtLMeSOQ

Is this pretty accurate? I can tell it gets power since it hums.


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## kok328 (Mar 8, 2018)

well, it hums because something is wrong.
could be not getting enough voltage.
that is why i asked about a meter.
you have a couple of choices here.
buy a meter and find the faulty component(s) or just by new until the problem goes away.
your first and cheapest option is to replace the capacitor.  if you don't have a meter to read it then maybe the supply house can test it for you.
otherwise, gamble $20, replace it and see what happens.
if capacitor is good and voltage is good then it will be the blower motor itself that is bad.


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## farmerjohn1324 (Mar 8, 2018)

kok328 said:


> well, it hums because something is wrong.
> could be not getting enough voltage.
> that is why i asked about a meter.
> you have a couple of choices here.
> ...



Where do I buy a capacitor from?

I've been reading that a capacitor problem can originally trace back to a blocked filter. All these problems started when I changed the filter. I don't get why a brand new filter of the same size and brand as the old one would cause an issue.


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## kok328 (Mar 9, 2018)

Graingers can hook you up. 
Youll need the rating or just take the old one with you and they might test it for you too.


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## farmerjohn1324 (Mar 10, 2018)

Where do I buy a multimeter with long terminals like that? The terminals on the ones from HD/Lowe's are so short, I can't even trust that they're working in this application.


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## slownsteady (Mar 10, 2018)

Is the motor free to spin? Nothing fell in or is resting against a moving part? Just a couple of simple things to check.


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## farmerjohn1324 (Mar 11, 2018)

slownsteady said:


> Is the motor free to spin? Nothing fell in or is resting against a moving part? Just a couple of simple things to check.



It spun freely. My multimeter told me zero for the capacitor, so I'm guessing that's it unless my meter is not good enough.

Do you know where I can get one with long terminals?


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## kok328 (Mar 11, 2018)

farmerjohn1324 said:


> It spun freely. My multimeter told me zero for the capacitor, so I'm guessing that's it unless my meter is not good enough.
> 
> Do you know where I can get one with long terminals?



Zero what?  Chances are the meter you have is not capable of reading a capacitor.
Graingers can hook you up with the appropriate meter too.
but at this point far cheaper to gamble on a new capacitor.


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## farmerjohn1324 (Mar 18, 2018)

Replaced the capacitor. Still doesn't work.

I noticed something I didn't notice before. The blower motor can be spun by hand only when the power is off. As soon as I try to send power to the motor, it locks up and can't be spun.

Does this mean I 100% need a new motor? Where do I find one?

And why would all this have started when I changed the filter? I replaced an old, dirty one with a brand new one of the same size and brand.


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## farmerjohn1324 (Mar 20, 2018)

Will a 3 jaw puller like this work to remove the blower motor from the wheel?

https://m.harborfreight.com/3-piece-three-jaw-puller-set-8832.html?utm_referrer=direct/not provided

Or do I need a hub puller like this?

https://www.walmart.com/ip/FAN-BLAD...4529&wl11=online&wl12=108472120&wl13=&veh=sem


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## kok328 (Mar 20, 2018)

Yes the motor is toast and it had nothing to do with the filter change it was purely coincidental.
No, you do not need a puller to change the motor.
You managed to get the blower and housing out of the unit, that is good.
Now you need to loosen the set screw on the hub of the blower wheel with a long handled allen wrench.
Then remove the 3 motor frame bolts from the housing.
From there you can separate the motor from the wheel and housing and will be able to see the "nameplate" info on the motor to order a new one.
Again, Graingers has your back.  The only reason I recommend them is that they will sell to you without a contractor's license, can locate just about anything and is a common name when I don't know what suppliers are around your locale.


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## farmerjohn1324 (Mar 20, 2018)

kok328 said:


> Yes the motor is toast and it had nothing to do with the filter change it was purely coincidental.
> No, you do not need a puller to change the motor.
> You managed to get the blower and housing out of the unit, that is good.
> Now you need to loosen the set screw on the hub of the blower wheel with a long handled allen wrench.
> ...



Thank you.

I pulled this screw out with an adjustable wrench. Is this the set screw you're talking about? I took out the 3 motor frame bolts also.

I still can't get the motor detached from the wheel. There's a piece I can turn independently of the wheel (red arrow in picture) if I hold the wheel still, but this doesn't cause the motor to come loose, even after turning it with a wrench for several minutes in either direction.


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## farmerjohn1324 (Mar 20, 2018)

Doing some research. Pretty sure I need a hub puller for this.


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## lou-in-usa (Mar 21, 2018)

Pull the capacitor out, it's usually strapped to the blower housing. Look at how many microfarads and volts it's rated at or take it to an electronics store. Or look on eBay, just make sure you get a replacement with the same values. Thief melting frost on the a coil could have damaged the capacitor, rusted the shaft at the bearing on the motor and caused it to seize, or otherwise damage the blower.

Before you put it all back together, consider doing a thorough cleaning of the a coil. If you ran it any length of time without a filter, or that was a normal practice from a previous owner, then putting a filter in now, won't help the fact that you're coil fins are clogged with garbage and causing a lack of airflow and therefore causing your coil to freeze up.


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## farmerjohn1324 (Mar 21, 2018)

lou-in-usa said:


> Pull the capacitor out, it's usually strapped to the blower housing. Look at how many microfarads and volts it's rated at or take it to an electronics store. Or look on eBay, just make sure you get a replacement with the same values. Thief melting frost on the a coil could have damaged the capacitor, rusted the shaft at the bearing on the motor and caused it to seize, or otherwise damage the blower.
> 
> Before you put it all back together, consider doing a thorough cleaning of the a coil. If you ran it any length of time without a filter, or that was a normal practice from a previous owner, then putting a filter in now, won't help the fact that you're coil fins are clogged with garbage and causing a lack of airflow and therefore causing your coil to freeze up.



Okay.

I already tried changing the capacitor. Didn't help.

How do I clean the evaporator coils? I had planned to clean the blower wheel also if I can get it off.


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## lou-in-usa (Mar 21, 2018)

If your blower is not spinning when you switch the thermostat to "Fan On", then that is your first priority, because cleaning the coils won't make the blower spin!  If you know how to use a voltmeter, you can see if you have line voltage (~120 VAC), across the  wires connecting to the fan motor, but you have to know which wires you should be seeing voltage on, and that depends on you being able to understand a wiring diagram that may be inside your cabinet, or maybe one you can find a schematic online; blower motors can be single or multi-speed, and you have to know what color wire you should expect voltage on. Maybe someone else here can help with that. Also note that induction motors almost never burn-up, and you if your motor did, you'd probably detect the acrid smell of burned/melted wiring insulation. What typically happens, is the bearings wear to the point where the rotor becomes off-center enough that the magnetic phasing that would normally start the motor spinning, can't because it's uneven. Another thing, if your squirrel-cage is so rusted onto the motor shaft that you need a puller to remove it, I'd bet the bearing part of the shaft is also rusted and ruined the bearings, and it doesn't take much for the rotor to be too far off center to prevent the motor from starting.

If you have no voltage to the motor, and you don't hear a relay click when you switch on the fan, then I'd bet your water, got to the fan relay or some other electronic component, in which case you should call a professional.


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## kok328 (Mar 22, 2018)

farmerjohn1324 said:


> Thank you.
> 
> I pulled this screw out with an adjustable wrench. Is this the set screw you're talking about? I took out the 3 motor frame bolts also.
> 
> I still can't get the motor detached from the wheel. There's a piece I can turn independently of the wheel (red arrow in picture) if I hold the wheel still, but this doesn't cause the motor to come loose, even after turning it with a wrench for several minutes in either direction.



Yes, that is the set screw I was referring to.  Try a little liquid penetrating oil on the shaft and hub.  If you've loosened everything up, you should be able to use a hammer and drive the shaft out of the hub.  Be careful not to distort the yolk on the fan hub.  I've never had to use a puller on these before.


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## farmerjohn1324 (Mar 26, 2018)

Does anyone know how to hook these wires up?

7 wires total. The ground is obvious, as are the 2 for the capacitor.

That leaves me with a black, blue, red, and white. I believe that the black, blue, and red are all hot wires, and the white is a neutral.

From the wiring diagram, it looks like I might be supposed to pick one of the hot wires, and cap the other two? What do I connect the "chosen" hot wire to? I believe this fan is only one speed, so which do I pick?


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## farmerjohn1324 (Mar 26, 2018)

farmerjohn1324 said:


> Does anyone know how to hook these wires up?
> 
> 7 wires total. The ground is obvious, as are the 2 for the capacitor.
> 
> ...



Okay I Googled it. 

The white goes to neutral, obviously.

And I'm supposed to pick ONE of the hot wires, and cap the rest. Generally, I pick the highest speed.

And it only makes sense that the previous wiring had a yellow neutral and blue hot.

Not really sure where to attach the ground wire to, but maybe it will become obvious when I get it back in.


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## farmerjohn1324 (Mar 28, 2018)

I have a few questions about the disconnects.

Can I crimp them with these wire cutters, or do I need a special crimping tool? The wires pictured are from the old motor. The old motor had more plastic insulation than the new disconnects that I bought. Do I need to buy additional insulation to attach the these new female disconnects?

Also, I can't quite figure out how to reattach the neutral (yellow) wire to the unit. It had two yellow wires (one from motor, one from elsewhere) going to a connector within the unit. (Pic attached of connection before it was disassembled). Now I'm looking at all these same parts, and can't figure out how to connect two female disconnects to the same terminal.


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## farmerjohn1324 (Apr 14, 2018)

Is there any way to know which of the secondary voltage wires from the old transformer (red or brown) is the Common "C" wire, and which is the "R" wire? 

The new transformer does not come with wires attached, but labels terminals "R" and "C."

If there's any clue, the two terminals on the circuit panel they were connected to are labeled "C" and "T" but I don't want to assume anything and guess wrong. The brown was connected to the "C" and the red to "T."


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## farmerjohn1324 (Apr 14, 2018)

What is going on here? I needed 18 gauge wire for the 24V transformer wires. I bought 18-2 wire, sold as "thermostat wire" and cut off the sheathing. The 18 gauge wires that were inside (red in the picture) are WAY smaller than the 18 gauge wires that I see elsewhere. The red and white thermostat wire fit in the 22 gauge space in my wire cutters.


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## kok328 (Apr 14, 2018)

farmerjohn1324 said:


> I have a few questions about the disconnects.
> 
> Can I crimp them with these wire cutters, or do I need a special crimping tool? The wires pictured are from the old motor. The old motor had more plastic insulation than the new disconnects that I bought. Do I need to buy additional insulation to attach the these new female disconnects?
> 
> Also, I can't quite figure out how to reattach the neutral (yellow) wire to the unit. It had two yellow wires (one from motor, one from elsewhere) going to a connector within the unit. (Pic attached of connection before it was disassembled). Now I'm looking at all these same parts, and can't figure out how to connect two female disconnects to the same terminal.



Yes, you can crimp with the wire cutters.
No, you don't need different connectors but, a better brand would have been nice.
To connect two females to one male, you need the adapter piece that was under the yellow wires.


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## kok328 (Apr 14, 2018)

farmerjohn1324 said:


> Is there any way to know which of the secondary voltage wires from the old transformer (red or brown) is the Common "C" wire, and which is the "R" wire?
> 
> The new transformer does not come with wires attached, but labels terminals "R" and "C."
> 
> If there's any clue, the two terminals on the circuit panel they were connected to are labeled "C" and "T" but I don't want to assume anything and guess wrong. The brown was connected to the "C" and the red to "T."



Yes, energize the primaries on the transformer and then use a volt meter from one secondary wire to ground.  If no voltage then that is the common wire.


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## kok328 (Apr 14, 2018)

farmerjohn1324 said:


> What is going on here? I needed 18 gauge wire for the 24V transformer wires. I bought 18-2 wire, sold as "thermostat wire" and cut off the sheathing. The 18 gauge wires that were inside (red in the picture) are WAY smaller than the 18 gauge wires that I see elsewhere. The red and white thermostat wire fit in the 22 gauge space in my wire cutters.



If your saying the wire size is different AFTER stripping the insulation then one or more of the wires are not the size they claim to be.
Also, you can reduce the wire guage slightly with wire strippers, especially with solid core but, should be that noticeable when stripped using the correct slot on the strippers.


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## farmerjohn1324 (Apr 14, 2018)

kok328 said:


> If your saying the wire size is different AFTER stripping the insulation then one or more of the wires are not the size they claim to be.
> Also, you can reduce the wire guage slightly with wire strippers, especially with solid core but, should be that noticeable when stripped using the correct slot on the strippers.



Well Home Depot better give me my 40 cents back or I'm gonna raise hell.


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## farmerjohn1324 (Apr 15, 2018)

For the secondary voltage wires, one end must be screwed to a terminal on the transformer, the other must be connected to a female disconnect. I must use solid wire because stranded won't screw well onto the transformer screws. Therefore, I must solder the other end to the female disconnect.

How can I do this when the disconnect is wrapped in plastic?


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## farmerjohn1324 (Apr 15, 2018)

Once again, I buy "18"-2 thermostat wire, this time from Ace Hardware, and it is not 18 gauge.


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## farmerjohn1324 (Apr 20, 2018)

I hooked all,this up,today,and it worked fine.

I put the motor on "low" because that's what the old one was on. Is that okay?

This is the new motor, new transformer, new capacitor.


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## tuffy (Apr 20, 2018)

Nice job


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## kok328 (Apr 26, 2018)

farmerjohn1324 said:


> I hooked all,this up,today,and it worked fine.
> 
> I put the motor on "low" because that's what the old one was on. Is that okay?
> 
> This is the new motor, new transformer, new capacitor.



I would expect the circuit board to have multiple speed terminal (low,  med & hi).
the control board will select the speed based one mode setting (fan, heat, cool).


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## farmerjohn1324 (Apr 26, 2018)

kok328 said:


> I would expect the circuit board to have multiple speed terminal (low,  med & hi).
> the control board will select the speed based one mode setting (fan, heat, cool).



The old motor had low speed connected and high speed capped with a wire nut. I just copied how it was.


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## kok328 (Apr 27, 2018)

farmerjohn1324 said:


> The old motor had low speed connected and high speed capped with a wire nut. I just copied how it was.



I understand but, what you copied was incorrect.  You'll stand a chance of freezing up the coils if you run it at low speed.


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## farmerjohn1324 (Apr 27, 2018)

kok328 said:


> I understand but, what you copied was incorrect.  You'll stand a chance of freezing up the coils if you run it at low speed.



So which should I connect to that terminal on the circuit board? Or should more than one of the speeds be connected? If that is the case, I don't know where to connect any of the additional wires.


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## kok328 (Apr 28, 2018)

farmerjohn1324 said:


> So which should I connect to that terminal on the circuit board? Or should more than one of the speeds be connected? If that is the case, I don't know where to connect any of the additional wires.



should be designations for lo, med, hi on the board where the low is plugged in now.
motor should say which color is which speed.
you may have to crimp a connector onto the capped off wires to connect to the board


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## farmerjohn1324 (Apr 28, 2018)

kok328 said:


> should be designations for lo, med, hi on the board where the low is plugged in now.
> motor should say which color is which speed.
> you may have to crimp a connector onto the capped off wires to connect to the board



I know which wires are for low-med-high coming out of the motor, but not sure for the circuit board.

I'll take a look at the circuit board tomorrow.


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## WyrTwister (May 1, 2018)

It is not uncommon , as has been said , for heat & cool to run different indoor fan speeds .

     I personally would run it on high , Iif you can only connect 1 speed .

     All this brought to mind , all the things that I take for granted / do automatically when trouble shooting , that the OP had to learn .  And the tools I take for granted that he had to gather up .

     I am blessed .

Wyr
God bless


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## Dennis Palmer (Jun 5, 2018)

This issue mostly occurs in an Air conditioner when the thermostat is not working properly, lack of power, or contacter problem. Check out all the mentioned issues and make sure they are working fine or you can call an expert to fix this problem.


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## Green8 (Jun 26, 2018)

Clear Duct System and Good Airflow | Common Air Handler Problems

Since the AHU is the central unit that moves the air throughout the ductwork it is important to make sure nothing obstructs the airflow through the air handler such as dirty or clogged air filters. A regular air filter maintenance schedule will help you maintain good air flow through the duct system. It also helps keep the air handler components inside clean and free of debris and dust. If you maintain good filter maintenance you will not have to worry about a dirty evaporator coil or any other components clogging with dust or debris. Furthermore, this includes closing off supply vents.

Blower Motor Failure | Common Air Handler Problems

The next most common problem that can occur with an air handler is a failure of a blower motor whether it be the blower motor or something else that causes the blower motor to fail. It could be a bad relay, control board, run capacitor or the blower motor itself. It could also be the blower wheel. These are AHU (Air Handling Unit) problems that need the attention of a professional HVAC technician. An HVAC technician can identify the problem quickly and make the repair. It may require ordering parts or the part may be available on the service truck but the problem will be resolved quickly and efficiently.

Proper Filter Maintenance | Common Air Handler Problems

Most of the issues described can be avoided with proper filter maintenance. Even the blower motor failure can be enhanced by bad airflow resulting from no regular filter maintenance. It makes the motor work harder creating more heat and pulling more amperage which costs you more electricity costs. The dirt from dust that builds up also hurts the motor and creates more heat which can have detrimental effects on the motor. Consequently, the lesson is to keep a good clean filter in the system and you will reduce any problems that may occur with your air handler.

Air Handling Units  | HVAC Airflow

Again, it is recommended that an HVAC professional do this work. Make sure you read the High Performance HVAC disclaimer before proceeding. A professional will have all the proper HVAC tools to complete the HVAC repair or maintenance job quickly and efficiently. It does not matter what type of equipment you have. You can have a Trane, Goodman, York, Rheem, or Carrier HVAC system and it all needs to be maintained. If you decide to do it yourself make sure you follow the safety procedures as noted on the Air Handler Page about cutting power to the air handling unit before attempting to clean the evaporator coils.

Basic Check | Common Air Handler Problems

See condensate drain section below for more information on this subject. Soak the air handling unit evaporator coil with a soap and water solution. Professionals use an industrial strength coil cleaner which may be available at some hardware stores. Let this solution soak for a few minutes. Then take a rag and wipe as much dust off the surface of the evaporator coils as possible. Repeat these steps until the evaporator coils look clean. Take a flashlight and look between the fins on the evaporator coils. The evaporator fin on the coil should appear to be clean. If not, soak the evaporator coils again and use a brush with light bristles to brush the evaporator coils.

Checking the Air Handler Blower Motor | Common Air Handler Problems

The air handler blower is comprised of different components in most units. It has an electric motor, a squirrel cage blower wheel, and a cage typically referred to as a squirrel cage. Some air handling units have belt driven motors and most have capacitors for the air handler electric motor and typically the only required HVAC maintenance on the blower is oiling the air handler blower motor if it has oil ports or checking the belt if you have a belt driven motor. Not all blower motors have oil ports. These blower motors use sealed bearings and never require oil. The air handler blower motors that do have oil ports usually have little plastic dust caps that can be removed so that oil can be applied.


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