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mr.coinring 05-24-2010 01:40 AM

York AC unit running slow...Please help :^(
I had to turn on the AC for the first time this season today and the vents were blowing out worm air.
I went out to check if the outside unit was on and it was.
The strange thing is that both the fan and pump are on but seem to be running much slower than normal.
The high line is not getting hot and the low line is not getting cold.

I believe that the fan and pump are single stage and the capacitor is a "dual run capacitor" not a "start capacitor"

Question is..
Can the dual run capacitor be bad but still be able to run the unit at a slower speed?
If the freon was low, wouldn't the low pressure switch not allow the unit to come on at all?
Is there anything else that can cause this?
Please help...Due to the economy I am unemployed and cannot pay to have a tech come out :^(

beenthere 05-24-2010 06:00 AM

Many units don't have a low pressure switch.

Good chance its the capacitor.

yuri 05-24-2010 07:32 AM

Yep, especially if it is visibly bulged/deformed looking.

mr.coinring 05-24-2010 11:16 AM

Guess I will try a new run capacitor.

In the event that doesn't work....what else can the problem be?

Might I add that I do NOT have to start anything by hand......Just seems like the pump and fan speed is at about 60%

Would it cut down the speed on the two if it were low on freon?

This unit is only about 6-7 years old.

I have read about a 24 Volts at a certain location on the unit.....can anyone tell me exactly where so I can check it?

At the contactor I seem to have 238 Volts

beenthere 05-24-2010 01:39 PM

A weak capacitor can cause the fan to run slower.

The 24 volts is the control voltage. Which has no bearing on compressor or fan speed. But would be checked across the contactors 24 volt coil.

Low of refrigerant wouldn't cause the fan to spin slower.

mr.coinring 05-24-2010 02:08 PM


Originally Posted by beenthere (Post 446396)
A weak capacitor can cause the fan to run slower.

The 24 volts is the control voltage. Which has no bearing on compressor or fan speed. But would be checked across the contactors 24 volt coil.

Low of refrigerant would cause the fan to spin slower.

I just installed a new dual run capacitor and it made no difference.

You say that being low on refrigerant will tell the unit to cut down the fan/pump speed to keep from freezing up?

beenthere 05-24-2010 02:10 PM


Meant to say that it wouldn't cause the fan speed to decrease.

Could have bearings tightening up on the fan motor.

mr.coinring 05-24-2010 02:52 PM

Fan bearings are great....spins rather easily and really smooth.

What else can make this whole thing slow down?

beenthere 05-24-2010 03:16 PM

Is it really slowed down. or does it just look that way to you, now that its not cooling right. Lots of people don't take notice tot he fan speed when their A/C is working.

You may have had 238 volts at the contactor when the A/C wasn't running. But what is the voltage when it is running.

mr.coinring 05-24-2010 03:35 PM

I take notice to the fan speed all the that its slower.....I can hear the pump, has a slight gargling buzzing noise, but I do believe its running. Figured it always sounded like that....just more noticeable with out the fan at full blast. Pretty much sound like a normal compressor to me.

I checked the Volts and it is 238 to 239 on the feed side when off.......and 238 to 239 on both sides when on.

In addition.....last year it was not working so well and the High line WAS getting hot, but the Low line was NOT getting cold.

Now it wont even do that.

beenthere 05-24-2010 03:39 PM

A slow running fan could cause the small line to get very hot.

So if its running slow, and the small line isn't getting hot. You have more trouble then just a slow running fan.

Might be time to bite the bullet, and call a tech to diagnose it. Might be a dirty condenser coil, and a low charge caused by a leak.

Have you checked the amp draw when the unit is running.

mr.coinring 05-24-2010 03:45 PM

I have a super fancy BluePoint digital volt meter I got From Snapon.

What setting do I need to have it on for that, and where do I check it? What should it be?

beenthere 05-24-2010 03:47 PM

Can that meter check amp draw on AC electric?

You would check it on one of the line voltage wires feeding the condenser.

mr.coinring 05-24-2010 03:50 PM

Guess its the DCA?

It has 200 with a backwards y then 2m, 20m, 200m, 2, 10

beenthere 05-24-2010 03:50 PM

Won't do AC amps.

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