Fridge compressor/ECM: Repair or replace?

[Suijin]

OK I'm no refrigeration expert, so I'd like a little advice and guidance.

The compressor or ECM on my fridge has quit. Turning it on results in a short tone, the fan comes on, but the compressor does not. The tone repeats about every 20 seconds or so as long as the switch is on.

A fridge tech came and looked at it. He checked the voltage which he assumed would be the culprit and it was fine. He is maintaining that given the age of the components that I should replace the whole system, and that there are no current parts that are compatible with the evaporator plates that I have, which look very much like the current plates on the market. He suggested a Sea Frost BDxp system. My box is around 10 cf, perhaps a bit more. The Sea Frost would come with an external electronic display/control, which would be nice. All I have now is an internal mechanical thermostat. The Sea Frost also has stainless evaporator plates, which are marketed as an advantage, I suppose due to durability, but I would think that aluminum would be more efficient in terms of heat exchange.

However, I really am not looking forward to dropping $3,500 on a new system. Am I really looking at replacing it end to end? If so, any opinions on Sea Frost?

Thanks a bunch.

[Vasco]

Had a similar problem once. Found out it was the ground wire. Hope your tech checked everything. If all the wiring is ok I'd give the compressor a good whack before replacing the system. (that's my usual fix for electrical motors, works great on windlasses ).

[Neptune's Gear]

Get another fridge guy.
The beep is telling you what is wrong, refer to the manual for this unit. Are there diagnostic LEDs on this model?
Compressor won't start for multiple, repairable reasons (of course it could also be knackered!). Low voltage, bad earth, low on refrigerant, overcharged etc etc. Looks like a danfoss compressor, so pretty common.
Richard Kollmann, a member here, has some good info on his website, Kollmann Marine
Good Luck!

[Richard Kollmann]

ANSWER
Suijin, Refrigeration repairmen can not show a profit repairing these small refrigeration systems or the tech you called got his business license from Hell. The beep sound and attempts to restart after 20 to 40 seconds is what I call the Danfoss control module’s microprocessor detecting an electrical fault that might cause compressor damage if not corrected. Most of the time no start problem’s are caused by a Old fan drawing too much current or a electrical fault with boats power grid wiring between battery and the Danfoss control module. It is also possible control module is faulty. On a unit as old as yours problem may be as simple as an old circuit breaker, switch, bad wire terminal connection, or old small gauge wire to refrigerator. Yes all parts are still available for this unit. The problem you have is generally correctable by boats owner after following these instructions:

Troubleshooting 4 pin modules consists of the following:

1. Thermostat Test, Not required on your unit at this time.
2. Disconnect black fan wire from electronic module, If Compressor runs, replace fan. Compressor still does not run after fan ground wire is disconnected go to next step.
If one of the 10 transistors in this fan fail it can cause module to prevent compressor from running.
3. Run correct size and correct polarity fused jumper wires direct from a fully charged battery to module in order to bypass all boat’s wiring. Volt meter readings are of no value, Forget what you think you know and think computer electronics. Compressor still does not run electronic module needs to be tested on another unit.

I closed my shop but after seeing what is being charged by boat refrigeration companies who will test modules charging $50 and charging as high as $385 for new 4 pin modules, I decided to test and sell modules for a fraction of what is currently being charged.

If your shipping address is in the US I will test your module on my Danfoss compressor refrigeration test stand. This test stand will run at max compressor load for a one hour. I will then return your module to you for a shipping and handling charge of $20. Email me if you need my help.

If you wish to purchase a new or serviceable unit from me later I currently have the following four pin modules:

Non Danfoss $150.

No used modules available at this time.

Modules will only be shipped to addresses in the US.

Because your unit is old and if it needs a new electronic module there is a risk that something is wrong that caused module to fail so most companies will refuse warranty of these modules. This is my electronic module warranty:
Any new module I sell can be returned for full credit without question within 30 days . Because of my own risk involved for the next 11 months I will return only 50% of the new units purchase price if module is returned within the first year.

Richard Kollmann
Richard@kollmann-marine.com
http://www.kollmann-marine.com

[lesterbutch]

I just recently got a new compressor for my refer. Try $1400 for one! I was lucky an electritian who was rewiring the whole boat had a brand new one he got free and he gave it to me! Helped ease the nearly ten grand rewire job! If I were you I would take the generous offer.

[Suijin]

Richard, thank you very much for your reply, diagnostic procedure, and generous offer. I'll do as you instruct and see where it leads.

The fridge is wired directly to the battery bank, with an inline toggle on/off switch. Should I still run new wire to diagnose? When you refer to "correct polarity", you simply mean to correct positive/ground, yes?

One note: I replaced the fan a couple of years ago, using a Noctua 120 mm computer fan. It has run faultlessly from then until this most recent problem. The old fan did not run at all.

[Richard Kollmann]

Unfortunately The only way to troubleshoot this older Danfoss compressor system is a process of elimination. The simplest and first thing to check is to remove module fuse located under the small gray plastic cover and inspect its contacts for discoloring do to heat. Clean contacts before pushing fuse back in.

Even if the fan is new remove any wires connected to F terminal, this will eliminate fan as a cause of compressor not running.

All of boats wiring can be eliminated if module + and – power terminals are connected direct to a fully charged battery. If unit runs on a totally separate power source then boats circuits can be tested by placing a jumper around each questionable wire and switch. Your problem may be as simple to fix as replacing a switch or circuit breaker or wire terminal.

Yes, module is electronic so plus and minus power wires Polarity is important.

Twice in the last year boaters have been told to replace their system and found that new unit had same problem as the old one did. This is why I always recommend eliminating all boat’s electrical wiring as a test..