Troubleshooting A/C compressor-capacitor part#?


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Old 06-03-08, 03:30 PM
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Troubleshooting A/C compressor-capacitor part#?

Frigidaire split system - compressor MDL: FS3BD-030K
Start Relay Kit 912933

1. Thermo - OK 26 VAC to the little-bitty circuit board outside
2. L1-L2 - Line in 240 VAC
3. Relay - OK 26 VAC across the coil - pulls in with no delay, but system has not cooled this season
4. T1-T2 - relay out terminals 240 VAC
5. T1 - Yellow (heavy guage) to compressor NOT warm
6. T2 - B/W (heavy guage) to compressor NOT warm
7. T1 - Yellow (light guage) to fan capacitor- Orange - to fan
8. T2 - Black (light guage) direct to fan
9. Fan capacitor - Blue - to fan
10. Fan capacitor - Red (light guage) to compressor
11. Fan starts "on demand"
12. Compressor never makes a sound.
13. Last season compressor had to try three times to start
14. Sounded like thermal overload would delay each try
15. Needs new thermal cut-out? Needs hard-start kit? Needs compressor start capacitor?
16. Where can I get the parts???

Any ideas would be appreciated.
Tnx
Jake
 
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Old 06-03-08, 04:06 PM
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Frigidaire FS3BD-030K: 13+ SEER, 2.5 ton condensing unit.

If the compressor does not make even a hush though the condenser fan is up and running, you could very well have a bad compressor.

Yes, the internal thermal overload could be the one holding it back from starting but the compressor should have started, ran for sometime, and only then the thermal overload would have come into the scene.

The manufacturer does not show (on-line) an schematic for this unit. If you could scan it I'd guide you with how to test the compressor...and/or you could take & post pictures as well.

Maybe the external overload is defective (that would be a blessing). This would be a small, black, cylinder-shaped device that you would hear snapping if the compressor was to take too long to start. This overload is of an automatic-reset type and is typically connected in series between the contactor and the common terminal on the compressor.

You could try buying parts at your local Johnstone Supply store, or even at a Graingers. Google them on the web.
 
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Old 06-03-08, 08:36 PM
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Tnx pflor...

I can't find schematic; I'm not well organized.

There are three leads to the black box on the side of the compressor. I haven't tried to get inside it yet. Two of them are line voltage leads yellow (T1) and black/white (T2). The third lead is red and runs back to parallel lugs on one pole of the fan capacitor. Another set of parallel lugs on the fan capacitor send a blue wire to the fan, and a set of 90 degree angled lugs receive a yellow wire also from T1 and pass it to an orange lead to the fan. T2 sends a black wire directly to the fan.

With the system on and fan running I used a digital meter to check voltages between the lugs of the fan capacitor and ground.

Yellow+orange 90 degree lugs to ground = 118 VAC
Blue lugs to ground = 294 VAC
Red lugs to ground = 118 VAC

Does the compressor start with 240 volts and run with 120?
Does the fan have start and run windings?

Still can't find the schematic. If it stops raining tomorrow, I'll try to get inside the condenser housing to get a picture of the compressor wiring.

More later
Jake
 
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Old 06-04-08, 03:15 AM
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Originally Posted by gingerjake
Does the compressor start with 240 volts and run with 120?
No. Your compressor starts and so long it's running, will do with 240V

Originally Posted by gingerjake
Does the fan have start and run windings?
Yes

Originally Posted by gingerjake
Still can't find the schematic.
It should be on the inside of the control box. I've also contacted the mfr requesting it. They are usually pretty good at helping with requests such as this. We'll see.

Originally Posted by gingerjake
If it stops raining tomorrow, I'll try to get inside the condenser housing to get a picture of the compressor wiring.
pictures will work great too.
 
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Old 06-04-08, 10:59 AM
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I'll look inside the housing for a schematic. Must have forgotten to look yesterday.

Found a site by Steve Arnold (I think) for parts and tips (www.arnoldservice.com). If it is the external overload automatic reset (most promising solution) and I replace it, I still would expect multiple start failures before the compressor kicks in like it was doing last season. To cure this problem Arnold sells a solid state hard start kit called the SPP6 or something like that. Would it replace the start capacitor on the compressor itself or work in series with the T1 line from the contactor inside the outer housing? If it's inside the housing with the other stuff, it wouldn't be out in the rain.{:-)

Jake
 
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Old 06-04-08, 11:39 AM
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I don't think your unit comes with an external overload (the schematic will tell), and it does not come with a start capacitor either, only a running cap (again, the schematic or pics will help). The hard start kit is a good idea, make sure you buy one appropriate for a 2.5-ton unit.
 
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Old 06-05-08, 05:57 AM
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Hi pflor...

Pulled the housing cover again thia a.m. and low and behold there is a schematic inside. I'm peruseing it as we speak.

More later when I figure it out.

Tom
 
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Old 06-05-08, 06:16 AM
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Does this look like the schematic for your unit? pls confirm.

Both (left and right) schematics are the same. The one on the left is called a "ladder", on the right is a "pictorial".

Check the one on the right, compare with your unit and tell me if the colors shown match what you have there.

Also notice the following:
1- The ASTC is an "option", you may or may not have it
2- So is the PTCR. BUT, if your unit has a PTCR, as per mfr, it should NOT have a hard start kit installed...if you still wanted it installed, the PTCR would have to be removed and modifications to the system wiring will need to be done
 
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Old 06-05-08, 07:58 AM
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This is the correct schematic.

Exceptions:
1. No PTCR
2. No crankcase heater
3. ASCT installed
4. No hard start kit

As you suggested, there is no external overload/overheat cut-out.

Fact:
1. With 240 VAC across the common (C) and run (R)terminals of the compressor it neither hums nor grunts.
2. Fan runs normally.

Hypothesis: Compressor internal overload permanently OPEN
Test: With all proper safety precautions, isolate dual capacitor H lead and C lead from T1. Check continuity between H lead and T1.
Result: If continuity, wiring to, or overload itself is open
Result: If infinite, start or run winding is open (OUCH)

I recall working on an Amana compressor once that had the overload mounted in the top of the compressor case. I replaced it and the compressor was fine. Is that possible with this compressor or is it dead.
 
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Old 06-05-08, 09:06 AM
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Tested as follows:

1. disconnected from dual capacitor:
a. H lead (red) to compressor start winding
b. C lead (yellow) to T1 to compressor run winding
c. F lead (blue) to fan

2. Resistance:

a. H lead to C lead = 3.1 ohms (windings intact)
b. H lead to T1 = 3.1 ohms (windings intact)
c. H lead to T2 = 8.8 megaohms (essentially open?)
d. C lead to T2 = 8.7 megaohms (essentially open?)

3. If the overload is stuck open, can I whack the side of the compressor (like we did to a voltage regulator in the old days) and get it to close again? {:-)

4. If not, can I replace the overload cut-out?

5. If not, is there anything else short of replacing the compressor (it's only four years old and still under warranty)

Many thanks for the help you've given!!
 
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Old 06-05-08, 10:12 AM
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You are very thorough!
Are you college age?

I want to make sure that you are testing the compressor properly. The black, yellow and red wires MUST be disconnected from the compressor terminals. Only then you may take ohm readings, and the procedure is as follows:

(1) testing for a short to ground --> one lead of the ohmmeter firmly touchin any metal copper pipe there, and with the other touch (one at a time) each one of the three compressor terminals (C, R and S). In each case you should get an INFINITY reading. Continuity on any of these 3 readings means a dead compressor

(2) testing for open internal overload --> one lead of the ohmmeter firmly on the C terminal of the compressor; the other first to the S terminal (take note of the reading), and then to the R terminal. If in either one of these two the readout is INFINITY, you have an open overload. If the compressor in not hot (touch it), the compressor motor is dead. If the compressor is hot, wait until it cools down and retake these two readings.

If you were to get a reading between C and R but infinity between C and S (or viceversa), a winding is broken, compressor is dead.


Answer to your questions:
your Q3 --> wacking won't help. Wacking helps if the piston is stuck, but not if the overload is messed-up
your Q4 --> no! these motors are not serviceable
your Q5 --> Your unit should still be under mfr warranty. I believe compressors come with a 10-yr mfr warranty. Contact Frigidaire/Nordyne and find out how are you to proceed in this situation. They'll likely expect a licensed contractor to do the job.
 
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Old 06-11-08, 01:28 PM
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Pflor...

Mea culpa, mea culpa, mea culpa and three saalams to the wise one from the east (New Jersey, I think).

If I had done what you TOLD me to do, I could have saved $300 and four days in 95 degree weather without A/C, but I was too lazy to crawl inside the condenser and check the compressor terminals themselves. The common lead was corroded, loose and making just enough contact to give a resistance reading instead of infinity.

I've learned my lesson; listen to the experts!

THANKS AGAIN!

p.s. I might have gone ahead and checked those terminals if I had known how frequently those spade and lug connectors corrode away (and in just four years). Looks to me like crappy engineering and manufacturing practice.

Tom
 
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Old 06-13-08, 06:20 PM
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Capacitor corrosion?

Hi gents,

Looks like you two were on an interesting path, one I might be able to benefit from.

We have a 5 ton unit outside that the blower motor doesn't start. The a/c serviceman came today, and basically said we should consider replacing the entire thing - partly because he could do a bunch of service replacing the capacitor which he said is bad, just to find out the fan motor actually went bad, and after replacing that, we might find out the compressor failed.

When he put the fuse in outside, you could hear the compressor start, and generating heat but the fan didn't blow.

After telling him I'd think about it (replacing it with an $4k unit), I started pulling things apart myself. I found the right part number for the capacitor and a source online. I could also find the fan motor as well I'm sure. I'd be very comfortable replacing both of those, and it would be well worth my time/money in case either one was the culprit...

One question - is it possible the capacitor connectors rusting could be causing problems? How do I test the capacitor to see if it's still viable (or do I just take his word that he tested it appropriately)? And if not - how long does it take for the charge in a 55/5.0 MFD capacitor to dissipate? It'll be at least 24 hours if not several days before I find a replacement - is that long enough?

Another question - if I replace the fan motor and cap, how likely is it the compressor has failed if it still makes sound and heat? And if the compressor has failed, I presume replacing that would mean replacing the refrigerant in the system (which I wouldn't have any clue how to do)?
 
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Old 06-14-08, 03:09 AM
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Originally Posted by dheista
We have a 5 ton unit outside that the blower motor doesn't start. The a/c serviceman came today, and basically said we should consider replacing the entire thing - partly because he could do a bunch of service replacing the capacitor which he said is bad, just to find out the fan motor actually went bad, and after replacing that, we might find out the compressor failed.
RUBBISH!!! that it is a bunch of work replacing a capacitor? gi'me a break!!! It takes a minute and they are cheap. This guy was shamelessly pushing for a sale.

Originally Posted by dheista
One question - is it possible the capacitor connectors rusting could be causing problems?
Yes, is possible. Buy yourself a bag of female quick connectors for the size wire you have there...the investment is less than 5 bucks and you'll have connectors for the next 5 years

Originally Posted by dheista
How do I test the capacitor to see if it's still viable (or do I just take his word that he tested it appropriately)? And if not - how long does it take for the charge in a 55/5.0 MFD capacitor to dissipate? It'll be at least 24 hours if not several days before I find a replacement - is that long enough?
If you can arm yourself with a digital clamp-on meter that has a capacitor testing feature I'll teach you how to do it.
Capacitors typically discharge rather quick, but to be on the safe side, all you have to do is jump across its terminals with the bare metal shank of a screw driver.
Finding a replacement should not take that long unless you live on the peak of mount everest. Google up for your local Johnstone Supply or Grainger stores. Buying a new dual capacitor (which is what you have there), should cost you less than $20.

Originally Posted by dheista
Another question - if I replace the fan motor and cap, how likely is it the compressor has failed if it still makes sound and heat? And if the compressor has failed, I presume replacing that would mean replacing the refrigerant in the system (which I wouldn't have any clue how to do)?
If you hear the compressor running and no fuses nor circuit breakers are tripping, your compressor is good. But making this tiny investment in a capacitor (and perhaps a fan motor as well...though try buying only the capacitor first) is well worth it. If it comes down to the compressor also being bad, then your best course of action is to replace the condensing unit, and yes, you need a professional to do that, it is not a job for the DIY.
 
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Old 06-14-08, 12:11 PM
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Shameless

Yeah - that's what I thought. Much easier for the repair guy to just follow the instructions of the boss and make a sale...

Anyway - I've looked on Grainger and Johnstone. Unfortunately there are no saturday-open stores close to me west of DC 40 miles. I did find several that are open M-F, and online - I found a few round cap at Grainger:

http://www.grainger.com/Grainger/wwg...x=0&submit.y=0

I had called FamousParts.com last evening (after they stopped shipping, and couldn't get something to my saturday delivery) and they informed me the part in my unit was a dual capacitor, and I'd need the following:
http://www.famousparts.com/g32-481.html

I could order from them, and maybe get it mid-week next week, but I won't be back here until the weekend and would like to get the parts early in the week and have a friend replace it for my family who's living in the house.

My question - is there a way to tell what Grainger cap I should use? I didn't realize there were "single" and "dual" capacitors - I presume that has something to do with the number of contacts on top (since there are 3 sets of terminals)?

It seems like this part from grainger:
http://www.grainger.com/Grainger/items/3GA13
is the right one. It says it replaces the same GE part number that the one from famousparts.com said I needed...

Anyway - I'm gonna either order from Grainger (at $5.39 instead of $37!) or hopefully have someone pick one up Monday morning...

In the meantime - I'm gonna yank the cap off the unit and go to home depot/radio shack and find some female connectors to replace the rusty ones on the wire anyway - will be happier with new connectors anyway.
 
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Old 06-14-08, 03:17 PM
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Yes, you have a dual cap there.

Are you sure is a 55/5? Yes, is a large unit (5 tons) the one you have, but still, it seems like the "55" is a bit too large. Double check.
You also need the voltage rating of the capacitor...370V? 440V? which is it?

Make sure you get an identical replacement.
 
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Old 06-14-08, 03:54 PM
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Cap with pics

Originally Posted by pflor
Yes, you have a dual cap there.

Are you sure is a 55/5? Yes, is a large unit (5 tons) the one you have, but still, it seems like the "55" is a bit too large. Double check.
You also need the voltage rating of the capacitor...370V? 440V? which is it?

Make sure you get an identical replacement.
Yeah - I've actually triple-checked the cap, and I've taken a couple photos in case you can verify?

Wish I had access to a capacitor tester. I only have a voltmeter, and don't see any cap settings. Only volts and resistance...



 
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Old 06-14-08, 07:56 PM
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goodness gracious!!!
those terminals look awful!

Yeah, get a new cap.
 
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Old 06-21-08, 07:14 PM
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Woohoo - fixed!

Just got the replacement capacitor, stuck it in, and the fan fired up just dandy! Thanks pflor - just saved me $3k - $8k which the repair guy said we should spend putting an entirely new system in, just because my $20 capacitor from Grainger needed to be replaced...

Another smashing success - lemme know if I can send a $100 gift certificate for Outback or McCormick and Schmick's to you!
 
 

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