Freezer keeps tripping circuit breaker

[alnelson]

Is it a Danfoss compressor?

[olivero]

Yes. Its a SC12CLX.2 compressor by Danfoss.

[alnelson]

Random breaker trips can be tough.

 

You could have one wire somewhere with a little chafe in it.

 

Or you could have a frame heater randomly grounding out.

 

For what its worth, for whatever reason I have had some of the danfoss compressors that intermittently won’t start, and the breaker trips before the overload on the compressor goes. But usually the breaker trips several times a day and not once a week.

 

Really, about all you can do is trace every wire and double check every part you can. If it has a drain heater, drain pan heater, or heated condensate pan be sure to check them closely. Even if they ohm out ok, remove them and give them a good visual inspection.

 

Look for arc spots, and sniff around for a burning smell.

 

Cycle the compressor on and off, on and off, on and off, and see if it consistently starts.

 

Good luck. I’ve had intermittent breaker trips that really fought me a long time.

[fixbear]

Did you check run amps? Also defrost amps. I have come across wiring in the wall that had a nail into it and only tripped when the wall was hit. Super hard to find, Try another circuit or feed before condemning the compressor..Also the defrost heater circuit in the evaporator will sometimes get a intermittent short from ice moving wires. Had a defrost thermostat that had a small hole in the wire that would run weeks before tripping from moisture shorting it. Look also for wire close to heater that has melted the insulation.

[olivero]

I did check run A and defrost A, about 10 A continuous. Doesn’t really change. I tried plugging it into a different circuit, blew the breaker anyways.

 

I have looked at every wire, and like mentioned in the original, changed most components, there are no connections showing any sign of being in any way, faulty grounded. We recently found the lead on the start relay, the spade connector was loose and had been arcing. We fixed that so we will see what happens now, its just strange it can blow a 20 A breaker every once in a while and when reset can run for days with no issues, to only make you think you finally fixed it and then blow again.

 

Its a real mystery this one.

[fixbear]

Ok, three things. The Socom (the Dutch company that bought out Danfoss and moved manufactoring to china) compressor has a top mounted compressor head and has to get oil from a internal pump in the bottom.I have one right now that squawks like a bearing bind when it stops. unit is 1 year old and was start relay rattling. I’m about to replace the compressor because the amp load is high. Be aware that Socom prices are very high.

 

     Second, if you have a megger and test the defrost circuit you may find the problem. It is very common to freezers to have a intermittent short or open due to the expansion and contraction during the freeze, thaw cycles. Look very closely, at the wires and anywhere that they go through the chassis. I have seen small pinholes from lightning in the evaporator area.

 

Third, the compressor motor is mounted on springs and free floats in the case.They have a stiff set of wires that go around the  motor 2/3rds of the way to take the torque and shake. Short of a charting recorder on the compressor itself, it’s hard to prove the short..

Best of luck.

[ectofix]

I’ve been there, so this might help.

Consider that nine amps is a relatively heavy sustained load you’re looking at.  So I’m presenting TWO other possibilities for you to explore:

It’s a faulty circuit breaker, or… There’s a bad connection of the wires connected to the breaker.

 

Before you shrug and throw those possibilities aside – first, consider this…even if this doesn’t solve your present problem:

 

From our own knowledge, we inherently suspect a breaker (or a fuse) to blow due to an over-current situation.  That’s what they’re designed to do – and it did it.  So…we go looking for the short-circuit that caused that, but can’t find it.

However…HEAT – due to a faulty wire connection to a breaker or a fuse block will also make them blow.  In fuse blocks, a poor connection between an actual fuse and the little springy tabs that secure it can be at fault.  Since it’s alive with electricity, it’s not like you’re going to reach out and put your fingers on it to see if it’s getting HOT.  So we simply, by default, look for a short-circuit.

 

Depending on the setup, there’s ways to catch this possible heat buildup.  In any case, it’s best to let that compressor run awhile so the sustained load is doing its thing to the electrical sources’ components and you can catch it in the act:   Let it run awhile (15-20 minutes).  Then:

 

Touch the breaker.  If it or connections to it are compromised, then the breaker body will be p-r-e-t-t-y warm (or HOT).  I’ll caution you that, even if you remove all power, touching hot (temperature-wise) wire connections might lead you to yelping out with some expletives. The second way is by doing a voltage drop tests at strategic points immediately going to the breaker, fuse block or actual fuse.  Test across the breaker with your voltmeter while the circuit is under a load. Test it wire in to wire out.  Terminal in to terminal out.  Whatever.  As the sustained current load has done ITS thing for awhile, do THAT to see if you see any significant voltage drop (approaching 1 VAC) across what oughta be a device with complete continuity (a continuous and non-resistive current path).  If there’s a significant voltage drop, then you have a bad connection or breaker. A third way to find this is with a laser thermometer.  Point and shoot it at the suspected faulty connections after it’s been running awhile. Believe me.  After you’ve pointed it around at some perfectly normal functioning connections, the faulty connection will stand out.

[ectofix]

Well forgive me for not noticing you said you’d replaced the breaker.  Nonetheless, I hope what I explained above can help out in the future.

[cliffie]

Usually when a piece of refrigeration equipment has a tripping problem you start troubleshooting with a load check (Amprobe check). If amperage is on the high side you need to check refrigerant pressure. High head pressure can cause an overload.

[badbozo2315]

I’d be putting in 3 fuses- small glass-fuse fuseholders, in these places:

 

1) Call me knuts, but one 20 amp fuse right at incoming power cord, before it gets anywhere else.

     It should blow before the breaker does. I know it’s on it’s own dedicated line, but… maybe not.

     If the breaker blows and the fuse does not, that tells you the line is not so dedicated, or that the

     night cleaning crew is plugging in that 20 amp floor buffer to the same outlet. 

 

2) One 15 amp fuse on the live going to the defrost circuit, as close to the power supply as practical.

 

3) Lastly, one 15 amp fuse at the compressor live, again, as close to incoming power as practical.

 

Total cost?  What, maybe $10 in parts.  It will tell you where to narrow down the search. I would not be changing out a compressor without knowing, for sure.