Diagnosis b4 repair

[tonigau]

I'm not a refrigeration tech, but want to identify most probable cause before taking to service to minimize their time (my$).

I have a 238L DC(12V/24V) fridge/freezer Beier BR238C4 that has developed a cooling problem - doesn't get cold.
This fridge did get returned to me once before with a not getting cold fault but it was working ok on test for a few days. Everything appeared normal.
It was suspected the solar system was insufficient (it was problematic due to a pressure water pump operating too often) or possible the bumpy ride of 200+ km's had a therapeutic effect on the fridge. it ran for another six months after.

I have checked for leaks with soap water on all accessible joints on the pressure side, both running & off. cant access the joints to evaporator yet as this needs surgery to the outer steel skin.(last resort)

The fridge has a 70w Domus DC compressor 3 phase BLDC, very simple refrigeration circuit, fan cooled condenser, capillary tube metering, on/off mechanical thermostat.

Any way here is a description of symptoms.
Evaporator not cold, compressor discharge pipe just warm, compressor suction tube just cool, capillary tube COLD, top section of check valve cold.
Compressor starts of with normal current of 6A, then slowly over about 100 seconds to 2.2A, RPM is constant.
For normal operation current will drop to 4.5 ~ 5A before thermostat cuts out.

Q. If there were a blockage/fault in the check valve would compressor current(work) be high. I would suspect so. ?

Q Because the compressor current is dropping well below normal would this be indicative of low gas charge(leaked) ?

Attached is a test done last year on same model (different unit) shows normal compressor current.

[mikeref]

Think your copper drier has fragmented. ( Left side of condenser fan.)
Answer to Q1: No.
Q2:Yes and no. If the cap tube is blocked, either from drier contents, oil logging or moisture then it would give you similar symptoms to a lost gas charge.

[mikeref]

In my opinion, every electronic appliances must be diagnosed carefully before repair.For More information please visit Deleted

Really?.... Would you care to expand on this statement and how this helps the O.P?

[tonigau]

Think your copper drier has fragmented. ( Left side of condenser fan.)
Answer to Q1: No.
Q2:Yes and no. If the cap tube is blocked, either from drier contents, oil logging or moisture then it would give you similar symptoms to a lost gas charge.

Thanks for the info, I'll see if I can get some spares from the OEM

So, just to confirm... a low gas charge could also cause cold cap tube ?, meaning the expansion (phase change) of refrigerant is occurring well before the evaporator.

T4

[mikeref]

If there is a pressure difference from one side of the drier to the other then this will cause the outlet side of your drier to go cold. Pressure drop caused by obstruction.
Amps will drop as compressor is not able to do any work.
These fridges carry very little refrigerant so only a tech who is competent on portable fridges can sort this out for you.

[tonigau]

Got a local refrigeration service to look at the fridge.
Pressure test indicated the system was not very low / out of refrigerant.

He removed the filter/drier, I cut it open & found what looked like the cause.

It looks like the capillary tube was inserted too far in the F/D & was touching the stainless steel filter mesh.
This would significantly reduce the filter surface area, & when some minor contaminants built up a blockage was likely the result.

Its now running good & cold.

Thanks for all the advise

[mikeref]

Yes. Seen that situation before. Poor workmanship. A plus for you though, not having the mesh punctured and causing drier contents to block the capillary.
Thanks for posting the pics and letting us know what the problem was.