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Help Troubleshooting A/C Compressor

20 posts in this topic

For my home central A/C, I have a copeland zr49k3 compressor unit feeding a Ruud Air Handler.

Currently, the air handler is running, but it is not blowing cold air. I believe what is happening is that the compressor turns on, then blows the circuit breaker and shuts off, leaving the air handler running.

Can anyone suggest steps for troubleshooting the problem - steps, tests, etc.?

Thanks.

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First you need a volt-ohm-meter. Do you have one?

What makes you think the unit stops due to a breaker? Did you reset it and it tripped again the next time the condenser tried to come on?

If you have a bad compressor , it is very easy to check if it is tripping a breaker. A compressor tripping a breaker is dead in most cases.

Need more info to help.

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Yes, have a multimeter. Let me know what to test for and happy to provide more data.

The circuit breaker was tripped 2x - first time a month or two ago, second time last week, though we haven't had that much use of the a/c - and the unit came back on when breaker was reset. I could be mistaken or could have been coincidental but that seems about right.

Today, I opened up the compressor unit and tried to turn on the A/C. I left it on for not more than about 30 seconds. Breaker did not trip, but the compressor got very hot so I shut it down.

Is it possible that the freon leaked out of the system? A few weeks ago, I cleaned the air handler - don't think I did anything to damage it, but could I have possibly have done something which would have caused a small leak?

Again, if you think there are any steps I should take to help provide more info, happy to do it.

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ok, from what you tell me it sounds like maybe the condenser fan motor is not running and the compressor is overheating to the point of tripping a breaker(maybe). Does the outside fan run with the compressor?? if not either bad fan motor or bad fan capacitor.

If condenser fan motor runs , but compressor overheats and trips breaker within a short time period, then maybe a bad compressor capacitor.

It is likely you have a duel capacitor and it may be partially or compleatly bad. Look at the capacitor . it should have a totally flat top. if it swollen at all , and if you see any oil or wax leaking. it is bad .

I will tell you how to test a CAP with a meter if you think that may be the problemmage.gif

Edited by ACtechGUY

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I agree with AC. Capacitor most likely.

post-2707-0-44218300-1301410452_thumb.jp

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Hey applianceman . Should I be worried that I know that picture is a carrier condenser? I would hate to go grey before my time.

fakenopic.gif

Edited by ACtechGUY

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Many thanks for the info.

Tested again today. You are right - the fan that draws air through the heat exchanger was not spinning. The compressor ran for no more than 30-60 secs but the area below the fan where the heat exchanger is was hot so I shut it down quickly.

I took the fan out of the housing and it spun freely, though had some built up grease/dirt on it (see picture here: https://picasaweb.google.com/asheitner/AirConditioner#5589626265199270450'>https://picasaweb.google.com/asheitner/AirConditioner#5589626265199270450). I did not see a fan on the compressor.

I also took some pictures of the electronics. See album here: https://picasaweb.google.com/asheitner/AirConditioner#

The capacitors looked ok to me, though one of them had some rust on it. https://picasaweb.google.com/asheitner/AirConditioner#5589626327737377826

Also, on this picture, you can see that there are 2 wires that go to nowhere (brown and clipped yellow one at the top) - not sure if this is supposed to be the case or if it's an error: https://picasaweb.google.com/asheitner/AirConditioner#5589626277781490674

Suggestions for next steps?

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WOW!! That was close !!!! We just had the worst hail/ wind storm any grey haired person can remember. Dude my siding and plants are shreaded...

Back to your problem..... Judging by the first photo , your condenser fan motor is failed. You see all the oil??? that used to be lubricating the motor bearings. NOw it is not!!! MOTOR VERY DEAD my friend.down.gif If the compressor is running, the condenser fan will always run at the same time!!! Didn't you hear the sqealing noise it was making before it stopped working?wink.gif

# 2 .... The electrical box is a mess. all those capacitors MUST BE strapped down. The person who changed the start and run capacitors did real Crap-Tastic work. If you know who did it , don't let them work on your unit again.nuke.gif

When you buy a new motor , Also buy a new Duel capacitor . I see from the box(!!!! THAT SHOULD NOT BE THERE!!!) that you would need a

50 / 5 Microfarad at 370 volt.

The small device with the cut wires is(WAS) a time delay device. It is there so that if you have a brown out(power flicker) the condenser will not come back on for 5 minutes. Not really critical , most low end units dont have them at all. But if it were in the circuit it may save the compressor in the event of bad power event.

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Thanks again. I do remember who worked on the unit prior and had an intuition that they did crappy work, which is why I wanted to diagnose myself this time.

OK - will look for a new fan motor and capacitor - any suggestions how to id the proper fan motor and where to source it? I did see the grease but the fan turns pretty smooth - i.e. not seized or metal on metal sound/feel to it.

When I re-assemble, what is the best way to strap down the capacitors and organize them better?

I'm in FL, so power flickers are a reality...how do I spec a time delay device and where can I get one of those?

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ON the motor will be a label. it will list horsepower (HP) , RPM and voltage. that is what you need yo know to find a new motor. Make sure you find one that says it is for a rheem or rudd unit. Most replacement motors will NOT have the mounting screw holes in the side of the motor case. The way the motor mounts in the unit is done only by rheem/rhudd so most motors will not work as a replacement.

YOu will also need to replace the capacitor for the motor.

We strap down capacitors with perforated strap and self tapping screws. http://www.google.com/products/catalog?q=perforated+strap&hl=en&rlz=1C1GPCK_enUS388US388&prmd=ivns&biw=1024&bih=655&bav=on.2,or.r_gc.r_pw.&um=1&ie=UTF-8&cid=7458507581129347817&sa=X&ei=qGCUTcLRHoi6tgeny5yFDA&ved=0CHIQ8wIwAA#

Here is a link to a delay on break timer that will replace the device you havehttp://www.gsistore.com/icm203fb-delay-on-break-ti.html

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Fantastic, thanks.

Will take a look at the motor for specs and will shop for the properly spec'd capacitor.

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:wallbash: Clean up will ya. Look at the terminals on the capacitor (burnt), power leads on contactor (cut back, strip, re-insert)

BTW it states 60/5 mfd 370 Volt not 50/5. Also all that schmootz on the bottom clean it. :yucky: Get some foaming bathroom cleaner and clean the coils. :thanks:

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hey bud i see you also have a potential relay on your unit, do a few simple checks, check line voltage first, then you need to check both capacitors with a meter that reads microfarads, if your contactor is closed and your voltage is ok is your compressor and fan running? this should be an easy fix.

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and also that time delay relay is on the control voltage side, it job is to prevent shortcycles. if your contactor pulls in its ok.

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Many thanks again for the replies. Few more questions:

1. Having trouble locating the correct motor. The numbers/specs that came off the motor are: GE S325XPV# (stamped on the motor body) GE 325S, 1/3 HP, 200-230V, A 1 60 are written on the bar code/label. I can't seem to locate this motor via google search (at least by that model number). Any suggestions for this motor or a comparable replacement?

2. I lifted up the 60+5/370 capacitor to plan for strapping it down and uncovered the top part of another capacitor underneath: https://picasaweb.google.com/asheitner/AirConditioner#5592121902240002706 and https://picasaweb.google.com/asheitner/AirConditioner#5592121902657001138 The capacitor is not connected to anything. Was this the one that was previously used and broke but was replaced by the silver cylindrical one? If so, should I just remove this "Ultramet" capacitor to make space for the new capacitor?

Thanks.

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hey bud this is simple. forget about the cap that is not connected, you have a dual cap, just buy a third horse, 208 230 generic condensor motor, you need the proper rpm as well, its either 1075 or 1725, and also buy a new run cap,

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Thanks. I ended up locating an a/c supply house nearby and went down there for all the stuff. They didn't have the motor in stock and thought it was worth a try with just a new capacitor. That seemed to do the trick - the fan turned on and the unit is cooling properly again. They guessed that when the fan was not turning on, the freon was staying hot and would no longer condense, which overheated the compressor and caused the breaker to trip.

I also bought coil cleaner, so will be cleaning those shortly.

Also, I bought a new time delay ("delay on make") so when I figure out how to wire that up, will get that installed as well. The old one was a "delay on break" - that should not matter, should it?

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no no no, high head will not trip a breaker, and why you wuould just replace a capacitor on a guess, any good supply house carries these simple everyday motors, i dont get it.and you dont either. do me a favor and call a qualified tech, for your own safety, i mean no harm but i see your lost and guessing?????? which concerns me.i use a meter you should too ok.

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no no no, high head will not trip a breaker, and why you wuould just replace a capacitor on a guess, any good supply house carries these simple everyday motors, i dont get it.and you dont either. do me a favor and call a qualified tech, for your own safety, i mean no harm but i see your lost and guessing?????? which concerns me.i use a meter you should too ok.

:wallbash: Since when will high head pressure not trip a circuit breaker I've seen it many of times. Most electrical problems are created from poor mechanical problems. Back when Glenn Henigan (Copeland's head Engineer) he made various presentations dealing with this fact.

Copeland had a series of manual's I will see if I have the pdf version. :thumbsup:

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Also, I bought a new time delay ("delay on make") so when I figure out how to wire that up, will get that installed as well. The old one was a "delay on break" - that should not matter, should it?

Big difference between these two devices,. A delay on break will prevent the unit from restarting for 5 minutes whenever you lose 24 volts to the condenser( like when it cycles off , or when the power fails to your home). The condenser will start instantly on a call for cool because that 5 minutes likely elapsed while the system was idle.

A delay on break will prevent the unit from STARTING for (?) 5 minutes EVERYtime the condenser gets a signal to start.

so everytime the thermostat calls for cool , the blower will run , but it will take 5 minutes for the condenser to come on every time. not desirable at all.

Edited by ACtechGUY

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