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Repair Or Replace Your 12 Volt Refrigeration?
The pleasure boat refrigeration industry today is following marine industry down the drain. We have seen refrigerator companies like Grunert, Crosby, Adler Barbour, WAECO acquired by Demitic. Bay has stop production of their boat refrigeration products. Northern Lights, a manufacturer of marine generator sets has acquired Ft. Lauderdale-based Rich Beers Marine. What seems to be missing in this new market are the experienced people that provided technical after market support in the past. The technical approach to small boat refrigeration today is the same as when you buy a toaster, if it does not work after a short warranty it is expendable so they advise you to buy a new one. The most resent loss to small boat refrigeration support is the announcement from Rparts.com that they will discontinue operations of Refrigeration Parts Solution Effective June 30, 2010.
If someone tells you to buy new 12 volt refrigeration because compressor will not run do not believe them. If your compressor runs but there is no cooling then solution is difficult and generally requires technical help. If compressor fails to run then anyone with basic technical knowledge can find and correct a failure to run of a Danfoss compressor. If your refrigeration unit is over 10 years old and has a Danfoss BD 2 or BD2.5 or BD3 compressor then it has the older discontinued electronic 4 pin module.
Troubleshooting Danfoss compressors with 4 pin modules will consists of the following steps:
1. All of these compressors have a 4 pin module connector and their modules contain an external fuse. If this fuse is blown there are two reasons why either power wires to module are reversed or module has an internal failure.
2. Check to see that there is actually power at the refrigerator control module.
3. Place jumper wire across thermostat terminals on electronic module, Compressor still does not run go next step.
4. Disconnect black fan wire from electronic module, Compressor runs, replace fan. Compressor still does not run after fan ground wire is disconnected, go to next step.
5. Run correct size and correct polarity jumper wires direct from a fully charged battery in order to bypass all boatís wiring. Volt meter readings are of no value when looking for voltage spikes. Compressor still does not run electronic module needs to be removed and tested on another unit. If there are no other units available to test your module on I will test all 12 volt Danfoss control modules free except for BD80 compressor modules. Email me for shipping address and details. firstname.lastname@example.org
VARIABLE SPEED DANFOSS COMPRESSORS
Small 12/24 volt boat refrigeration using Danfoss compressors manufactured after 1996 will have a BD 35 or BD 50 variable speed compressor with a troubleshooting computer chip built into their control module. This circuit makes them easier to find troubled area if compressor fails to run. If your unit does not have this $2 LED install one, as it could save you a lot of money later. Without the LED on these new units troubleshooting will be the same as earlier 4 pin Danfoss BD compressors.
If installed trouble shooting LED will only flash if electronic module sees a compressor problem. In each case problems of compressorís failures to run are identified by Counting number of flashes of LED:
∑ Two LED flashes indicates fan over current cutout. If fan circuit on these variable speed compressors exceeds Ĺ amp compressor start up will be aborted. This condition can be confirmed by disconnecting Black fan wire at module if fan runs replace fan.
- No LED flashes would indicate either thermostat is open or no power to module.
- One LED flash and a 4 second pause indicates a boat wiring electrical resistance problem or low batteries. Because of modules sensitive to milliseconds of a voltage spick they cannot be detected by a voltmeter. Solution is to bypass boatís wiring till problem is located.
If someone has tampered with refrigerant by connecting gauges to a system letting air in or adding too much refrigerant can cause either a Three or Four LED flashing signal. On water cooled Danfoss condenser systems three and four LED signals are common when seawater gets into refrigerant circuit.
If you have sources for refrigeration fair priced parts and technical assistance email them to me and I will list them on my web site. I found a source for 4 pin modules at a fraction of the price currently being asked and have been advised that refrigeration parts outlets like United Refrigeration can special order the newer Danfoss modules or compressors at a fair price.
- Three LED flashes indicate excessive torque is required to start compressor. This is commonly caused by turning compressor off and back on too quickly or too much refrigerant or poor condenser cooling. Most people jump to the conclusion that there is a mechanical rotor lock up inside compressor and this is a mistake on Danfoss BD compressors.
- Four LED flashes indicate compressor motor not reaching sustained controlling speed above 1,850 rpm quick enough.