Fridge Follies - Adler Barbour

[Doug]

If you want to get to the HEART of the matter first, go to the very LAST post on this topic on page 3.  It's by Richard Kollmann, noted and respected boat refrigeration guru.

Went to the boat after work tonight for a quick Bourbon and water before heading home and found there was no ice. The fridge had quick sometime since the weekend and everything was warm and melted.

Fridge is and older Adler.

I checked the wiring. A little corroded. Trimmed and cleaned, but still had nothing. Fuse at the panel and on the control unit are good.

Testing voltage showed 12 V at the control unit when the wires were disconnected from the control unit, but when they were hooked up they read zero.

Lines also tested 12 V at the panel, and I had good conductivity down both lines.

Any thoughts? Anyone swap out the control unit with the $200 unit Defender sells?

[steve stoneback]

Doug,
You didn't mention the stat, did you check to make sure it wasn't accidentally turned off and it is working properly?  It happened to me one time and after trouble shooting for an hour I checked the stat........ and yep, it was off.   I am sure you are hoping it is something that simple.
Steve

[Stu Jackson]

Was the muffin fan at the compressor/condenser coil working?  I've swapped out two of these in the past eight years.  They cost $45, way less than replacing the compressor.

[Ron Hill]

Doug : The only trouble that I've had with my unit was when I accidentally disconnected the thermostat 2 wire connection near the hull just aft of the rear water tank (my compressor unit is on the aft starboard side).  See if that connection is good.

This is an old contact, but for a rebuilt ECU try Miller Marine (904)388-3690.  Talk to Linda or Al.   

Also, I never let my boat connected with the fridge ON, unless I'm on the boat.  Just think of the wear and tear that you are putting on the batteries, charger and the fridge unit!!  I usually arrive at the boat with a small ice chest with ice and a cold beer.  Much simpler that letting every thing running ( and wearing) with the threat of a lightening strike/power surge on a near by power line.  A thought.    

[Stu Jackson]

One of the references is: http://c34.org/bbs/index.php?topic=980.0

Try searches on refrigeration, fridge, Adler Barbour, etc.

Lots of reading and ideas.

[SteveLyle]

If you send the control unit to AB, they'll test it for you.  They'll also walk you through a simple ohm meter test you can do on it.

Sept. 2014 - They stopped doing this, but Richard Kollmann will. http://www.kollmann-marine.com/Performance%20problems.aspx - Stu

[Doug]

Lesson learned:

I tested the wiring, fan, switch, and everything else.  I'd get power to the unit, but once I put a load on it (connect fan or compressor) the power would drop from 12 V down to about 2 V, followed by a slow recovery.

When testing the switch and fuse holder on the panel I dropped the fuse. Was easier to put a new one in than find the old one.

Yep. It was the fuse. 

Of course, I had visually inspected the fuses when it first happened, and they were fine.  I've never see a fuse do this: It looks good, was intact, and tests full continuity. But run even a minor load through it and it looses most of its conductivity.

System works fine, but I have another question: The fan is blowing towards the compressor, not the condenser. In other words it draws Air through the coils and blows towards the pump.  Seems to me it should be blowing the other way. I can't reverse the fan electrically, and it's been hooked up that way since I got the boat. The fan is from radio Shack so it's a previous owner fix.

Which direction is the air flow on an unmodified factory unit?

[Ron Hill]

Doug : I'm not on the boat so I'm not sure which way the fan should blow. 
However, the compressor does get very warm so it may not be a bad idea to pull air thru the condenser coils and blow it toward the compressor. 
Call Adler Barbour and ask them.   

[Randy and Mary Davison]

Just to fill in the blanks - I did put in the defender control unit and it works great.  I've also had to replace two thermostats over 9 years as they corrode into non function.

[Castellanet]

Doug -

I was the one to wire that fan, it was broken when I bought the boat, my first repair.  I do recall some issue installing it one direction over the other, but thought it a temporary fix . That Radio Shack fan was not completely compatible, I intended to find the proper fan, since that one draws twice the AMPs as the original, and probably blows too hard.  My search for the right fan was fruitless, and that Radio Shack fan turned out to do the job.

Glad to hear you are getting to the bottom of the wiring issues, replacing the charger, etc.  I fixed the running lights, that fan, replaced both heat gauge and sending unit, and some other minor things like the flourescent light in the head. Good job replacing the entire engine panel harness, taking out all that tape, the owner prior to me didn't do well back there.

I haven't looked at this board in a few years, but wondered about the old boat as I am re-writing the sales agreement, preparing to buy my next one - boatless for a year!  (Well, I'm 1/3 partner on a 26' racer, not the same.)  Glad you are enjoying.

Craig

[Stu Jackson]

The muffin fan we had is an NMB, Model 4710NL-04B-B30, 12V DC, 0.32A, DC brushless fan motor, Minebea Co. Ltd., Made in China.  Measures 4 3/4 inches square, holes are 4 inch on center.  No doubt could find a replacement at Radio Shack.

The fuse idea is very good, and I'm planning on replacing all of mine, including the one in the A/B unit.  Don't forget to change the panel fuse from the listed 15A on the panel to match the 10A in the A/B unit.

[jmnpe]

Doug, I feel your pain. As soon as I read your posting I was saying to myself "It's the fuse", having repeated your scenario myself at least once. Turns out Ohm's Law still works.... If you measure voltage until you add a load, it almost always means a bad connection, including a bad fuse.

The fan draws air through the evaporator and discharges it across the compressor as it comes from the factory. However, AB will tell you that it is OK to reverse the fan so that it blows the other way if that allows you to get the hot air away from the unit more effectively than with the factory configuration. Sometimes the factory configuration will draw cool air into a compartment, but without enough pressure to get the hot air out, and you end up getting a terrible heat rise in the compartment.

John

[Stu Jackson]

Another question about fridge operation:

I've noted that when either shorepower or alternator charging is not present, AND when the batteries ARE charged, our ammeter jumps to past 10 amp draw when we turn the fridge on.  Sometimes it goes back to rest at 5 amps, showing the fridge is on.  Sometimes is drops back to zero and the fridge isn't working.  Sometimes it doesn't jump and goes to 5 amps and the fridge is working. 

When shorepower or alternator charging IS present, when the fridge is turned on it just normally goes to its 5 amp draw and doesn't jump on the ammeter.

I am planning to replace the fuses as suggested in this thread, and to check all the wiring connections at both the panel and the unit.

Any observations on why the ammeter and the fridge might be doing this?

[Craig Illman]

ok, my THEORY.  Every motor when it starts pulls an intial high amp load momentarily. When you're on batteries, the batteries may not react as fast to the high current demand as the charger can on shore power.

- Craig

[jmnpe]

Stu,

I'm not sure that I have a good complete explanation for what you are seeing, although I have some observations and maybe a related explanation.

All of the Adler Barbour compressors made before about 1998, give or take, had a very high starting current of 17 amps at a nominal 12 volts. The "newer" ones are started gently by a more gradual application of voltage to the motor, rather than the "slam" start used in the older units. When the source impedance of the voltage source is very low, as it would be with well changed batteries that are well connected to the load, the starting transient only lasts for a short period of time ( 100 milliseconds +/- ??? ), and then the motor comes up to speed quickly enough that the high current doesn't last long enough for an analog or sampled digital ammeter to ever register the current spike. This is apparently just what you are seeing when you have a charging source connected to the batteries ( i.e. - the alternator or shore power ), and is in fact what you should generally see with batteries only. However, the fact that you see the weird, somewhat erratic current demonstrations when there are no charging source sources applied to the batteries makes me suspect that the compressor is seeing a badly sagging voltage at times.

Since low voltage will make a DC motor draw more current, I suspect that the long-enough-to-see ammeter reading at about 10 amps is when the motor is unable to get up to speed enough to cause the motor current to decrease to the lower correct value associated with higher/normal operating speed. When the 10 amp reading is maintained and the fridge continues to operate, the compressor motor continues to see a low voltage. When it goes to 10 amps, but then comes up to 5 amps, the compressor motor slowly managed to get up to "normal" operating speed, and the current reduces appropriately. When it goes to 10 amps and then shuts down, you probably had a voltage present that was low enough that the built-in low voltage shut-off of the compressor controller shut it down. All of this is, of course, long distance educated guessing.

The short answer is that I think you have a connection problem that is minimized or eliminated when you have either of your charging sources applied to the DC bus. What you should be looking for is a wiring configuration where the charge sources are connected ( in either the ground or 12 volt side, or even both ) electrically "closer" to the feed points to the fridge than the basic battery feed point connections. The problem you are looking for is between the batteries and the charge source connection points in the DC distribution paths. The way to get started is to connect your digital volt meter between the battery terminals and their respective path ends right at the compressor feed terminals on the compressor "pallet", and look for voltage drops across the 12 volt path, and then the ground path.  Once you find an obviously large voltage drop, start moving your measurement point away from the battery end of the path and closer to the compressor. From what you are describing, I wouldn't be surprised if most of the drop is in only one feed line. The voltage drop should mostly go away by the time you reach the point where your charging sources connect along the paths. The internal fuse in the control unit or the fridge CB should be okay since they have to be down stream of the charge source connection points into the DC distribution busses.

Hope this gives you some place to start looking.

John