Bus Fridge Dead Need Help/Advice

rv_safetyman · December 26, 2010, 10:47:29 AM

One of my Christmas presents was going out to the shop to get a bunch of pre-prepared food out of the bus fridge -only to find that it had tripped the breaker. Fortunately the contents were still cold!

This is a Sears side by side unit with water and Ice in the Door (Pat loves that). It is model 106.59292994. It was purchased in March of 01.

I did some playing, and with everything unplugged, the breaker is fine. As soon as you plug in the fridge the breaker immediately blows and it is dramatic. I will probably try an extension cord from the shop just to double check the breaker.

I looked at the parts list and the motor/compressor is an integral unit. There is a start relay/overload module and I will play with that as time permits.

So, the questions begin.

The first question is, what is the likelihood that the compressor has shot craps? It sure sounds like a stalled rotor situation. As I say, the unit is approaching 10 years old and it has bounced around a bit over the past 5 years. I don't recall using it that much while I was working on the bus, but it might have been in use most of the time.

The next question is, if the compressor is bad, should I have it repaired or replace the unit? Newer units are probably more efficient, but I am pretty sure I would have to take this out through the windshield

. It came in through the door, but I have built some jams and that might not allow it to come out that way. May be able to take out a side window - will have to measure.

If the prevailing thought is to replace, installation is not a big deal, as it is not built in yet.

If the thought is to replace, any strong recommendations on manufacturer?

Thanks, Jim

Sean · December 26, 2010, 11:27:58 AM

Jim,

While it does sound like a stalled compressor, I would not rule out other causes. I would try bypassing the thermostat and circuit board and connecting the compressor directly to a 20-amp HACR circuit to see if it starts.

If the compressor is seized, it is almost a certainty that a whole new fridge will cost you less than a repair. Sad but true; we live in an era of disposable appliances. If it is just a hard start, changing the breaker to HACR type if it is not already, and/or a hard start kit might help. Or the refrigerant level may need adjustment, which any HVACR tech should be able to do.

-Sean
http://OurOdyssey.BlogSpot.com

Ray D · December 26, 2010, 12:13:09 PM

Sounds like something has shorted, if it was a locked rotor, you would here a hum and then the overload safety on the compressor would open, the breaker tripping immediately is typical of a short. Don't forget the defrost system also. If the compressor mortor burned up, get a new one, it could have contaminated the whole freon system.
Ray D

robertglines1 · December 26, 2010, 12:26:03 PM

Jim think your on right track ck clean supply to unit first. Bob

Len Silva · December 26, 2010, 12:37:45 PM

I agree with Ray. A locked rotor is not going to give you the immediate trip. More like a hard short someplace, shouldn't be too hard to find.

rv_safetyman · December 26, 2010, 02:56:27 PM

Wow, thanks guys.

The breaker is a Blue Sea - the type used in a marine panel. I am sure that it does not have a delay feature.

You are giving me hope that it is not the compressor.

In the next few days I will move it out from the wall and see what I can see.

Jim

Sean · December 26, 2010, 04:10:42 PM

Quote from: rv_safetyman on December 26, 2010, 02:56:27 PM
The breaker is a Blue Sea - the type used in a marine panel. I am sure that it does not have a delay feature.

Actually, Blue Sea breakers (which, IIRC, are actually made by AirPax) are the magnetic/hydraulic type and most have delays. You need to look on the side of the breaker for the delay or the part number, which will specify the delay curve. May or may not be correct for compressors.

-Sean
http://OurOdyssey.BlogSpot.com

Hard Headed Ken · December 26, 2010, 05:43:28 PM

Jim,
I had about the same problem with my home fridge, which is similar to yours and about the same age. I checked every thing I could think of and I was convinced the compressor was locked up. I called the repair guy because the compressor was still under warranty. Turns out it was the start capacitor. According the repair guy most manufacturers have started using a cheaper design that's not very reliable. (It doesn't look like any capacitor I've seen) Of course it wasn't covered by the warranty.

Ken

rv_safetyman · January 01, 2011, 05:27:26 PM

I finally got a chance to take a look at the back of the fridge. The connection to the motor/compressor was really burned up. It came apart in many burned pieces. It looks like it plugged onto the compressor which has three prongs.

My parts manual shows the three prongs but it is not clear what plugs onto it. I think it is a part that has the description: "Start Device, Combination (start relay and overload)".

Will try to see if I can look at the part at the Sears repair facility.

The obvious question is: did the part fail on its own, or did a bad motor/compressor cause it to fail. Will probably try to get the part and see if it works.

Jim

Update. I did some poking around and found the attached photo. My start device did not look like the one shown. As I say, mine came out in a bunch of charred pieces.

papatony · January 02, 2011, 12:54:56 AM

If you have a ohms meter to check the comp. put the black lead to the body of comp. and touch each of the leads. If the meter goes to 0 ohms on any of the leads you have a short thus a bad comp.

oldmansax · January 02, 2011, 04:07:43 AM

Jim,

You can buy a new generic start kit, which contains all the correct components, from your local HVAC supplier. I used to carry them on the service truck all the time. They come in a 1HP & below, and bigger than 1 HP. You refrigerator should use the smaller size, obviously. They will have install directions on them.

TOM

Sean · January 02, 2011, 05:17:13 AM

Quote from: rv_safetyman on January 01, 2011, 05:27:26 PM
...
The obvious question is: did the part fail on its own, or did a bad motor/compressor cause it to fail.
...

Jim, I should already know this, but my memory is not the best: Do you have a true sine wave inverter, or is yours MSW?

This would be exactly the kind of symptom I would expect to see over time on a MSW-powered compressor.

-Sean
http://OurOdyssey.BlogSpot.com

RichardEntrekin · January 02, 2011, 05:54:08 AM

Jim,

A couple of things to add to good comments from others. One, I have had a number of electrical connections fry like that, I attribute it to the vibration.

Second the fridge or compressor should have a locked rotor amperage LRA listed somewhere. Typical running amperage for my Amana side by side is about 1.2 amps, and the locked rotor is about 15 as best as I remember. You should be able to hot wire the compressor and hang a clamp on ammeter just to check it's condition.

If the compressor is shot, then working on a fridge is a lot different in some ways than other AC systems. A new compressor can be had for about 400 bucks, you will need a vacuum pump to evacuate the system, silver solder and torch to put the new one in, and an accurate set of scales for weighing in the refrigerant. There should be a tag in the fridge that tells you exactly how much gas it takes. More than that amount and the fridge will not get cold!!!! If you choose to have someone else do it, you are likely looking at the best part of a 1000 bucks IF they will work on it while in the bus. Many will hesitate to do the soldering while the fridge is in the coach for fire danger.

And, please clean the coils, and keep them clean. It's so easy to gunk them up while any kind of dusty work is going on. Like computers, the cooling fan sucks in the dirt.

robertglines1 · January 02, 2011, 06:26:14 AM

Dumb observation! low voltage = heat=failure? of wire connector

rv_safetyman · January 02, 2011, 06:42:14 AM

Thanks guys.

Tony, I will check with ohm meter before I buy the module. Makes sense.

Sean, the inverter is full sine wave.

Tom, several folks have the module online - $30. My part number is obsolete but the new modules have my number listed as being equivalent.

Richard, if the compressor is bad, I will get a new fridge. Pat is not all that happy with the freezer width. The unit is 10 years old and I would hope that the efficiency has gotten better over the years. My fridge is not yet built in and I have a little bit of flexibility on space. Do not look forward to getting the beast out, or getting a new one in.

If the compressor is OK, I am worried about the pins on the compressor. They look to have been damaged by the heat when the module failed. Any thoughts on how to deal with that? I had thought about cleaning and soldering on some electrical connections and then sort of "remote" the module. If they are damaged, I can see that there would be a marginal connection and heat issues.

Jim