Refrigeration problem

[Tom23352]

Went to the boat this weekend and found the A-B Super Cold Machine not making super cold. Plate was warm and the fan/compressor were cycling on and off. Went to the anolog amp meter and and observed that about 30 seconds after the fan started the amp draw would spike up about 10 amps then over the next few seconds would creep up another amp or two then abruptly drop back to baseline. Manual say expect about 7 amp draw. Confirmed it was the compressor cycling on and also noted a single flash pattern from the diagnostic led. This is supposed to indicate low voltage. The voltage regulater for the solar panels is indicating 14.03 volts at batteries and the charger is on (440 amp/hr bank of 6 volt batts). My meter shows 13.9v where the 8g wires enter the Alder-Barbour unit. I watched the voltage as the fan kicked on and saw about a 0.4 volt drop but when the compressor kicked on the voltage went to 5.9 then the compressor cuts out. The unit is about 6 yrs old. What is going on here?

 

[Stu Jackson]

Could be: http://c34.org/bbs/index.php/topic,2850.0.html

or needs a charge of refrigerant.

 

[Tom23352]

start simple

Right. Will run through wire and connections for corrosion, loose connection or both.

 

[DeniseO30]

Those modules that are on the Danfoss compressors are extremely volt and amp sensitive. Did you try it with the engine running? And yes cut and reconnect the ends of the wires. If it needs refrigerant it won't be apparent until it's been running a few minutes. You should hear some gurgling in the evaporator. but in a holding plate you may not hear it all.

 

[Richard Kollmann]

Ten amps on start is a bit high for a Danfoss BD compressor but possible if restart mode is being repeated. It is also possible to see 10 amps on start if someone has tampered with refrigerant.

If Adler Barbour unit was equipped with troubleshooting LED then it has a variable speed BD50 compressor with higher operating amperage maybe as high as 7 amps.


A LED signal of one flash every 4 seconds does indicate a low voltage spike not readable with a voltmeter. Correct polarity jumper wires need to be run direct from fully charged battery to Danfoss module eliminating Adler Barbour’s stainless box wiring and all boat wiring. Somewhere in this wiring is a high resistance connection only visible on voltmeter with Superman’s eyes during compressor start up.

 

[Tom23352]

Refrigerant charge has not been tampered with. What would compressor do if all the refrigerant has leaked out?

 

[Richard Kollmann]

If refrigerant is below normal level or there is no refrigerant in system compressor will run unloaded at low amperage draw.

Many times false compressor start up will be caused by too much refrigerant or contaminated refrigerant because someone incorrectly tempered with refrigerant.

Your problem seems to be electrical normally caused by incorrect boat wiring or a poor solder connection inside Adler Barbour's stainless steel add on box where the fuses and LED are located. If you were to search my refrigeration forum there are more than one problem reported on wiring in AB's stainless box.

 

[Ron20324]

What would compressor do if all the refrigerant has leaked out?

If I recall a previous car owner's manual, they tell you to run the airconditioner once a month in the off season so the refrigerant can lubricate the internal workings.

 

[kloudie1]

The car AC "run occasionally" is about lubricating the mechanical seal on the compressor drive shaft so that it does not dry out and leak refrigerant.. The Danfoss is sealed and has no mechanical seal because the motor and compressor are in the same housing..
Sounds like a bad connection since the voltage should not drop to 5.9.. It is probably going below that, even, and the meter is not picking up the absolute low voltage point.. All regrigerant leaked out?? many compressors have a low pressure trip that will not allow start if the pressure is too low.. I don't know if that A_B has that feature.. Some have a low ampere trip that will shut off the compressor if the compressor sees no load as when the regrigerant has leaked out.. Again, I don't know that particular unit.. Some will run with no refrigerant .. there is an oil reservoir in the compressor housing that will let it do that usually without damage for many hours .. Your symptoms sound like not enough voltage/amperage instead of not enough load ..
Agree with Richard and Denise..

 

[Tom23352]

Appears wire connection was the issue right at the back of the compressor. Unit has been keeping the freezer at 30 degrees for 2 days now with boat interior at 86. Will run through entire wire loop and inspect/replace all connections. Thanks all for suggestions.