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AC not working - House AC question...UPDATED: Now working :)

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https://sigforum.com/eve/forums/a/tpc/f/320601935/m/1340072034

September 12, 2017, 05:49 PM
ShouldBFishin
AC not working - House AC question...UPDATED: Now working :)
TempStar AC (installed in 2004) was working fine yesterday, today not so much.


Went out to the compressor and the fan wasn't running, but it does spin freely by hand - compressor was too hot to touch.


Disconnected power outside - plugged it in and heard a 1/4 second buzz, then click, then nothing. The fan did not spin.


The Run Start Capacitor was wet with oil on the outside. Got to the local plumbing and heating shop just as they were closing and picked up a new capacitor (Old one was 45/5uF, new one is 50/5uF if that matters).


Put the new capacitor in, connected power, same 1/4 second buzz, click but this time the fan started to spin, then nothing.

ETA: Compressor is a Copeland scroll ZR26KA-PFV 130. I just put my meter around the black contactor wire and it looks like it's drawing 68 Amps and 46 Amps on the red wire (if I'm reading those correctly) - wondering if the compressor is shot... Frown


Any ideas on what I should be looking at next?

This message has been edited. Last edited by: ShouldBFishin,
September 12, 2017, 06:25 PM
thezoltar
Sometimes there are 2 50amp fuses located next to the outside unit in a box of their own. I've had them blow two different times. They are the large shotgunshell sized fuses. If they sound like a salt shaker when you shake them the internals are blown.


======
...welcome to the barnyard...some animals are more equal than others
September 12, 2017, 06:28 PM
Oz_Shadow
No idea if this could be it, but there's a thing called a Contactor

One of the connection pads fell off mine and stopped it. There's 110 and 220 feeding it. Replacement was $40-50 I think.
September 12, 2017, 07:07 PM
ShouldBFishin
quote:
Originally posted by thezoltar:
Sometimes there are 2 50amp fuses located next to the outside unit in a box of their own. I've had them blow two different times. They are the large shotgunshell sized fuses. If they sound like a salt shaker when you shake them the internals are blown.


Didn't think of those, but just checked the fuses and they're still good.
September 12, 2017, 07:12 PM
ShouldBFishin
quote:
Originally posted by Oz_Shadow:
No idea if this could be it, but there's a thing called a Contactor

One of the connection pads fell off mine and stopped it. There's 110 and 220 feeding it. Replacement was $40-50 I think.


I'll take a closer look at that, but I was able to manually push in the contactor (I was measuring amperage around the black and red wires when the connection was made).
September 12, 2017, 07:37 PM
M1Garandy
quote:
Originally posted by ShouldBFishin:
quote:
Originally posted by Oz_Shadow:
No idea if this could be it, but there's a thing called a Contactor

One of the connection pads fell off mine and stopped it. There's 110 and 220 feeding it. Replacement was $40-50 I think.


I'll take a closer look at that, but I was able to manually push in the contactor (I was measuring amperage around the black and red wires when the connection was made).


I had bits of fried capacitor fall down (mounted inverted) and jam the contacts of the contactor up. That took a bit of investigation to detect after replacing the start/run cap.
September 12, 2017, 08:57 PM
lee40215
Compressor is hot and needs to cool off. The capacitor which was bad is used to start the compressor and fan motor. Give it 24 hours or trickle cold water over it for 5 or 6 hours then try it again.
September 12, 2017, 10:30 PM
Excam_Man
Model number... ? (T)2A330(*)KA(#)00... ?

The blown cap was the reason for the fan to fail to start.

Most likely the contacts on the contactor are arced enough to cause the compressor to fail to start.

When the unit tries to start (it hums), pulling more current then normal, which causes the high temperature limit to trip (the 'click' you're hearing). But the fan will continue to operate.

Replace the contactor and it might be fine.
If not, the compressor could be locked up or has a bad winding.

If it doesn't run after a new contactor, we can further diagnose.

BTW, you can wire around the contactor for testing purposes.

***Just looked up a T2A3 and 68 Amps is locked rotor amps. You need to check the compressor windings. If they check fine, you can try a 'hard start' kit, to see if the 'kit' will break the compressor's rotor free. You still need to change the contactor or wire around it, so you have a good connection for testing.




September 12, 2017, 11:43 PM
old rugged cross
I am betting the comp. is toast. If it isn't I would not invest much $ into it. Cause it most likely is not long for this world. The components and labor will nickel and dime you to death to ultimately figure out it is time to upgrade.

Time to start thinking about some new equip. is my best guess.
But EM is our resident expert on these matters.Smile



"Practice like you want to play in the game"
September 13, 2017, 03:57 PM
ShouldBFishin
Thanks for the input guys.


I work from home - except on Wednesdays. Hoping to get home before dark tonight so I can get the model number, check the windings and maybe bypass the contactor for testing.
September 13, 2017, 09:15 PM
ShouldBFishin
AC is working!


When I got home I checked the windings on the compressor, each of those had continuity. I checked the thermostat power at the contactor - at first it read 25 volts (when I had disconnected the power to the AC), but when I reconnected power to the AC I wasn't getting any reading on the thermostat wires. Replaced the batteries in the programmable thermostat, a 5 amp fuse on the furnace circuit board for good measure and it fired right up.


My guess is that the bad capacitor caused the fan to stop, the compressor to overheat yesterday and needed a significant amount of time to cool down (thanks Lee).


Again, thanks to all who took the time to reply. I really appreciate the knowledge of the Sigforum members.
September 13, 2017, 11:30 PM
old rugged cross
glad to hear it is working. The real question is for how long. Hope is like the energizer bunny for you. Wink



"Practice like you want to play in the game"
September 14, 2017, 12:09 AM
Excam_Man
So what's the model number and the compressor's RLA?




September 14, 2017, 08:44 AM
AJM
quote:
bad capacitor

Bad capacitor


ΜΟΛΩΝ ΛΑΒΕ
September 14, 2017, 09:40 AM
ShouldBFishin
quote:
Originally posted by Excam_Man:
So what's the model number and the compressor's RLA?


That tag on the outside reads:
Model N2A330AKA200
14.1 RLA 68.0 LRA


Should I be checking the amperage draw now that it's working again?
September 14, 2017, 09:41 AM
ShouldBFishin
quote:
Originally posted by old rugged cross:
glad to hear it is working. The real question is for how long. Hope is like the energizer bunny for you. Wink


Me too... It was 80 and humid in the house when I got home last night. Took quite awhile to bring that temp down.
September 15, 2017, 09:51 PM
Excam_Man
quote:
Originally posted by ShouldBFishin:
quote:
Originally posted by Excam_Man:
So what's the model number and the compressor's RLA?


That tag on the outside reads:
Model N2A330AKA200
14.1 RLA 68.0 LRA


Should I be checking the amperage draw now that it's working again?


Yes, it'll give ya an idea of how well its doing.




September 21, 2017, 04:29 PM
ShouldBFishin
quote:
Originally posted by Excam_Man:
quote:
Originally posted by ShouldBFishin:
quote:
Originally posted by Excam_Man:
So what's the model number and the compressor's RLA?


That tag on the outside reads:
Model N2A330AKA200
14.1 RLA 68.0 LRA


Should I be checking the amperage draw now that it's working again?


Yes, it'll give ya an idea of how well its doing.


So far so good - AC still works Smile


Weather warmed up a bit so I thought I'd run out and check the amperage draw when the AC was running.

Red wire read 5.5 Amps, black wire read 7.6 Amps.

Not sure I trust the peak reading on startup - that was really high @77 Amps (had the meter set to keep the peak reading while I ran inside and kicked the AC on).
September 21, 2017, 06:14 PM
old rugged cross
If I was in Vegas I would be placing my bet that it is on barrowed time.

But you have had a good run with it some when it does quit you cannot complain.

And again. I would look to replace the system all together with new equipment.



"Practice like you want to play in the game"
September 21, 2017, 08:38 PM
Shifferbrains
quote:
Originally posted by ShouldBFishin:

Not sure I trust the peak reading on startup - that was really high @77 Amps (had the meter set to keep the peak reading while I ran inside and kicked the AC on).



There will always be a high amperage spike when an electric motor starts, perfectly normal.