Amana compressor hot after cap replaced


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Old 05-05-14, 06:44 PM
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Amana compressor hot after cap replaced

Hi all, first time to post here but I read a ton of great info here all the time. I have an Amana system that is approx. 7 years old. Have had fan and compressor capacitors replaced previously, and yesterday it quit cooling again. I decided to have a go at it, and found the fan was running but the compressor was not. The compressor capacitor was slightly swollen, and tested bad with my DVOM. I bought a new one at lunch today and the compressor came on after I installed it.

I patted myself on the back and went back to work. I got home this evening and you guessed it, the house was hot. Same conditions as before, the fan on, compressor not. I checked for voltage in and out of the capacitor and all around the contactor. Everything seems to have power where it should. I decided to check power directly at the compressor and found that the compressor was too hot to lay my hand on for any length of time, even though it had not been running for quite a while (house was up to 80*). I just left it powered down to cool off.

Did I do something wrong? Or is my compressor toast? Any help would be greatly appreciated.
 
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Old 05-05-14, 06:53 PM
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The compressor thermal overload should reset itself.

I would:

1. Retest the capacitor - maybe something is killing it

2. Check the voltage at the contractor when the compressor tries to start -> you may have an electrical issue (the issue could even be the transformer on the street), but you have to rule out any issues in the house before calling the utility

Do the lights dim a lot when the compressor tries to start? Does it take several attempts for the compressor to start. You could try a hard-start kit* as a last resort.

*If you use a two wire kit, make sure it has an electronic potential relay
 
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Old 05-05-14, 06:58 PM
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Thanks for the reply Muggle. I'm not sure what a hard start kit is, but isn't that like a bandaid on a broken bone? I guess I don't know what all could induce thermal overload protection besides the obvious fan inop.

Also, when you are talking about checking the voltage, do you mean to see if it drops considerably?
 
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Old 05-05-14, 07:16 PM
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^Yup - check voltage at contactor when it starts. Also check the resistance across the contactor (t-stat calling for cooling, main power to condenser off and high voltage wires disconnected) -> worn contacts could be causing a voltage drop and preventing the compressor from starting. Starting current is 4-6 times running current.

Also check your outdoor coil for excessive dust/dirt buildup -> that could cause the compressor to draw excessive current and trip the overload.

Note: It's normal for that top of a scroll type compressor to be hot -> unless you've got a 13 seer system running r22, your unit most likely has a scroll in it.

A hard start kit is a capacitor and relay combination you put in parallel to the run capacitor which increases starting torque. If your system needs one (no obvious cause like low voltage issue or bad capacitor), it's not a patch - particularly if you've got a long lineset or expansion valve indoors.
 
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Old 05-05-14, 09:43 PM
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Thanks again for the info. It is indeed a scroll compressor. Could the need for a hard start kit increase over time, perhaps as the compressor ages? The contactor and compressor are original, but the fan and caps have been replaced. Not sure about the type of metering device. Will get out there tomorrow and check the contactor further.

Another question if you don't mind- Is checking voltage drop on Alternating Current the same as DC systems such as automotive? Just use a DVOM to check for the difference in voltage potential between 2 points while the circuit is operating?

Also, why are the wires between contactor and cap and between cap and compressor so small compared to the other wires to and from the compressor?

Again, I really appreciate all the knowledge you're sharing with me and others. I bet it didn't come to you as freely
 
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Old 05-05-14, 10:26 PM
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If you can start the compressor by using the run capacitor, you don't need hard start kit. Looks like compressor overheat, Wait it cools off, try to start it again. You mentioned small wires, the only small wires are the two 24V wires connected to the contactor, all others should be the regular wires.
 
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Old 05-05-14, 10:51 PM
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Another question if you don't mind- Is checking voltage drop on Alternating Current the same as DC systems such as automotive? Just use a DVOM to check for the difference in voltage potential between 2 points while the circuit is operating?
Yah - the meter should work that way whether you're operating on an AC or DC circuit. As long as there's a potential difference, it should pick it up.

Could the need for a hard start kit increase over time, perhaps as the compressor ages?
I could see that happening, but 7 years is pretty new.

Hard start shouldn't be needed in theory, but if it doesn't consistently start without one and there's no obvious cause, one should be added.

Definitely monitor the system a little bit -> See if the compressor sometimes doesn't start to begin with or cycles off after running for a while. (hard start won't help at all if it starts fine but cycles on overload after a while) If you've got a clamp ammeter, check the running amp draw.
 
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Old 05-05-14, 11:27 PM
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The sounds of it yes internal overload switch was tripped. This is a switch located internally mounted in common winding. It's a safety feature. Be careful handling swollen capacitors or inspecting visually with power applied. They can and will explode and cover you with hot oil and tin foil looking material.besides that it'll scare hell out you. Try again replacing capacitor. With the power SECURED remove housing top. Fan maybe mounted to this cover or have it's own 48yz frame mount. Remove lid careful of fan wiring. Some you can lean fan back and balance without disconnecting electrical. All power still SECURED get water hose with high pressure nozzle. Position hose to wash coils from inside out. Pay notice to base of coil where it and bottom plate meet. Remove any and all debris from that area as that's main flashing section of coils. Rinse complete coil. Rinse debris out of bottom of inside. Most have holes for drainage. Once inside thoroughly washed rinse outside coils in a downward sweeping motion. You do not want to bend or fold in coils but enough to pass thru coil. After rinsing is over reassemble unit. Turn thermostat off or set to highest setting. Restore outside power. Go back to stat run down until stat is calling for. operations. Check operations is all equipment online? You now need a volt ohm amp multimeter. Using the amp probe setting check amps at contractor on both fan compressor and then over all amps. Compare your findings to data given on data plate.listen to unit does anything sound as if it's laboring. For instance is fan whining or slight grinding. Compressor is it at norm sound level is it whining knocking vibrating hard. If none of this applies amps with in given guidelines all should be good. If unit compressor continues to malfunction do install electronic hard start potential relay circuit to aid compressor start. Cleaning unit will make big difference in amp draw. You may test overall amps before then after cleaning to compare. If a Bristol brand compressor they need hard start kit due to start design. Short cycling of electricity can be major cause of this issue.
 
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Old 05-06-14, 06:54 AM
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I got a feeling you are out of refrigerant.
 
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Old 05-06-14, 07:10 AM
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Wow, awesome info everyone. Coil is clean but never paid attention to very bottom areas. Always figured if 95 percent is clean, then I'm good. Could be 7 years of crap in there and I wouldn't know. Will look today at lunch. I don't have an amp clamp but I think a buddy at work does. Will check it out and update asap. Thanks again.
 
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Old 05-06-14, 07:13 AM
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Apprentice, certainly never to argue, but only to learn, what makes you say that about the refrig level? Without telling me how to check pressures, can you tell me if there a way to check without breaking forum rules?
 
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Old 05-06-14, 12:52 PM
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Symptoms of low refrigerant charge:

- Insufficient cooling*
- Indoor coil freezing up, starting only from one side*
- Warm suction line*
- Sound of gas bubbles running through liquid line -> you should have a full column of liquid

*Restriction can cause this symptom.
 
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Old 05-06-14, 01:35 PM
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"Hotguy"(I feel weird saying or writing that.) The reason I think it may be out of refrigerant is I have a hunch that the compressor is off from the overload because of running without refrigerant for an extended period. It's rare to see a unit go off from the overload for extended amounts of time just because of a bad capacitor. Little or no refrigerant often causes the compressor to overheat and shut off, sometimes for several hours. A bad capacitor usually causes the compressor to shut off for only a couple of minutes.

Its just a guess. Lots of variables and hard to say with any certainty, without seeing it.
 
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Old 05-06-14, 05:49 PM
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HaHaHa! Sorry Apprentice, I was trying to think of a quick user name to register on the board. I was referring to my condition, definitely not my looks!!

I couldn't get my hands on an amp clamp, so I measured voltage drop across the contactor and everywhere I measured, I only read millivolts, so I assume the contactor is good (at this point).

I went ahead and purchased a 5-2-1 hard start kit and installed it. After comments here and further research, it sounds like a good idea to me. I fired it back up at lunch and it worked fine until I had to go back to work. Unfortunately, it didn't fix it. It shut back off from thermal overload I guess.

I'm heading out now to thoroughly clean the coil paying close attention like wwb371 said.

Also, clocert, compared to the other 2 wires to the compressor and all the wires to the fan, the start wires are much smaller in diameter. Maybe a third as thick as the others. I didn't cut one to see what the actual gauge is but I would guess 20 ga or so. All the other wires are big fat ones. Perhaps it's different insulation size and not wire gauge...

Thanks again for all the input.
 
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Old 05-06-14, 07:30 PM
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If the condenser is dirty, the liquid line will be very hot.

If it's low charge, the suction line won't be very cold.
 
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Old 05-07-14, 08:29 PM
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Just wanted to update this thread and thank everyone for their help. I stated that the hard start kit I installed didn't fix my concern, but I was wrong. After I got done installing the hard start kit, I reinstalled the disconnect and the compressor came on, and then the whole thing shut back off after about 5-10 seconds. I figured I was beat, and thought maybe the compressor locked up or something. I went ahead and cleaned the coil thoroughly, and then reinstalled the disconnect again. The unit fired up and then shut off like before. I was cleaning up and it fired up and has been running fine since. I guess there is a timer built in that I didn't wait to time out the first time. So, not sure exactly what was wrong, but the capacitor was definitely bad, and the coil was slightly dirty but not clogged by any means. Gonna go ahead and have someone come out to check the refrigerant level and make sure all is well. Thanks again for everyone's help.
 
 

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