How many bad caps have you seen???

[ameritech]

Have any of you guys ever seen a bad capacitor when changing out the start device on a compressor? I just thought I'd ask because I m going out on whirlpool GI5SVAXVB01 tomorrow and Im almost certain its a bad start device. In the past I've ordered the capacitor with it just to safe, but I dont want to waste my customers money if not necessary. I've had techs tell me they've NEVER had to change out caps. I've tried to test them in the past, but they never really seemed to test like they're supposed to.

What say you???

AmeriTech

[johntech]

On refrigerator star devices I used to change them along with the relay and over load just to be safe but stopped years ago. Since then I have actually seen 2 failed caps. One was exploded from a power surge I suspect and the other the leads were internally shorted. Not hard to test only takes a few seconds with the right meter. Lots of good videos on the net on how to test them but nothing beats the samurai academy courses. 

[Koi Guy]

The capacitor is a run capicitor, the compressor starts and runs even without it. It is used for making the compressor run more efficiently and that is it. 

[johntech]

7 hours ago, Koi Guy said:

The capacitor is a run capicitor, the compressor starts and runs even without it. It is used for making the compressor run more efficiently and that is it. 

They can be either start or run capacitors. The start capacitor will create the additional phase needed to get the motor turning then the relay will take it out of the circuit. 

[Hiroshi]

Start capacitors fail more often than run capacitors, in my experience... I have changed many washing machine start capacitors, and a few refrigerator URCO devices where the start capacitor puked- but very few refrigerator run capacitors, maybe 5 total.

 

[Koi Guy]

3 hours ago, johntech said:

They can be either start or run capacitors. The start capacitor will create the additional phase needed to get the motor turning then the relay will take it out of the circuit. 

Perhaps I wasn't clear... this unit uses a run capacitor that has zero effect on starting the compressor and keeping it running. But you are correct that not all capicitors are run capacitors. 

In addition to the OP's question, I am curious of how often someone actually checks the capacitor, and how would one suspect it to be failed? After all, it doesn't come in to action until the compressor has started. Personally, I can't recall having a failed RC, whith the exception of ones burned from the relay burning (think Maytag!). But, I can't recallseeing one failed by itself... but then again, how would I know?

I remember when the URCO410 came out, the beauty was the addition of the run capacitor leads, whereas the RCO410 did not have these leads.

On a side note, I can't think of a single residential refrigerator that uses a start capacitor on the compressor....

 

[johntech]

22 minutes ago, Koi Guy said:

In addition to the OP's question, I am curious of how often someone actually checks the capacitor

With a capacitance meter. https://www.amazon.com/capacitance-meters/b?node=5011682011

 

22 minutes ago, Koi Guy said:

I can't think of a single residential refrigerator that uses a start capacitor on the compressor....

Don't really run into them either but I have trained and seen diagrams of them so I figured since it was more of a general question on failed capacitors that just happened to list a model number I would not exclude them. 

[MoTeD]

I test them all the time because it is so easy with my meter. Have i had to replace them? Only a couple times out of hundreds of start relays/overloads.

[ameritech]

Thanks for the replys guys. Interesting to get all the knowledgable feedback. It was a bad start device. I had a hard start on the truck. Threw that on there - with old cap - working fine  http://www.appliancejunk.com/forums/Smileys/classic/cool.gif. I did test the cap for microfarads w/meter and it was on spec. Is that reliable way to check caps?

 

[J5*]

Bad caps , plenty on dryers , a fair few on dishwashers , rare on fridges

use a cap meter with the cap out of circuit to test correctly

they are marked with a tolerance 

some spit their guts but a lot just lose their rating , a bit like a flat battery 

every now and then i get one that is out by 10 to 20% particularly on dishwashers so cust complains of poor wash and you test operation is ok but once they get hot the motor cant work right 

[ameritech]

Thanks J5,

So on my multimeter I have a setting to test microfarad, I'm assuming this is all I need to check? Have you ever used the method where you discharge the cap, recharge it with your ohm setting on meter, watch the ohms slighlty rise, then they return to zero? Ive gotten that test to work maybe once...

Youve seen lots of bad caps on dryers? really? Not doubting you I've just never even heard of caps on dryers (in my fairly limited experience). I've never known a tech to find, much less test a cap on a dishwasher either. Have I been missing something these few years I've been in the field??

[johntech]

7 minutes ago, ameritech said:

Have you ever used the method where you discharge the cap, recharge it with your ohm setting on meter, watch the ohms slighlty rise, then they return to zero? Ive gotten that test to work maybe once...

It is not a difinitive test, meaning it can pass that test but still be bad since you are not testing the actual capacitance value just that it has  one. You would also want to test the terminals to the capacitor housing for a direct short. However I do use my analog meter on high voltage microwave capacitors on the RX10k setting. Same test the meter jumps when you switch the leads then goes to infinite. 

Most of the caps on modern dryers are built into the motors same on dishwashers. There are models that have the capacitor available as a separate part (mostly older models) but I don't see many. I normaly don't test thoes caps but diagnose them because the motor hums but doesn't start then if you manually turn the motor it jumps to life. Since they are only available as part of the motor assembly I just verify correct voltage and that nothing is obstructing the motor from turning. Most likely you diagnosed them as a bad motor and the new motor same with a new capacitor which would be a correct diagnosis since they don't sell the cap seperatly.

The most failed caps I'm seeing right now are on the whirlpool verticle modular washers. They like to explode. 

[J5*]

Being down the other end of the earth we prob have some different products 

but seeing caps in dryers here for last 30 years 

same with a lot of dishwashers 

as mentioned it often appears to be a bad motor but usually a bad cap but if its part of the motor then you are out of luck 

[ameritech]

Thanks fellas. And yeah jonhtech I forgot about checking for a short to housing... Thats what these forums are for lol