These Danfoss variable speed pulse driven three phase coil compressors require clean pure
current that can not be confirmed clean with a volt meter, this is why when operated on 12 or 24 volts during testing all boat’s
electrical system must be bypassed. To do this test run properly sized positive and negative jumper wires, protected with a 15 amp fuse, direct from
battery posts to Danfoss control module.
Three, four, five or six trouble LED codes indicate an overload condition caused by high amperage or dirty
electrical current not visible with a voltmeter. If module receives dirty
power is will not be able to produce steady pulses in all three field coils resulting in an over amperage starting load.
Your tests ruled out:
1. Thermostat by placing jumper on C and T.
2. Disconnected Fan.
3. Tested field coil resistance. This never fails to test good unless someone tries to
power compressor direct from 12 volts DC.
4. All 12v
wiring is in good condition. I Also tested connecting directly to the fully charged battery. Checking voltage is of no value with a voltmeter. Bypassing boat’s wiring and powering unit direct from battery is the only simple test for dirty power.
5. Replaced control module.
Common Overload conditions to the BD compressors are caused by:
Seawater interring refrigerant circuit on
water cooled systems.
Too much refrigerant in unit based on ambient system’s high temperature or someone tampered with refrigerant or just connecting a gauge to unit.
Mechanical failure in a BD compressor is very unlikely.
If tests were done correctly you now must believe both modules are at fault.
If you want to send the original module to me I can test its operation on 12 volts only and return it to you. If it does test bad I will loan you a good 12/24 volt unit to try at no risk to you if you return it within 30 days.