CoolMAtic Refrigerator issue.

Robski97

Robski97

Well-Known Member
Jan 15, 2007
1,828
North Bellmore, NY
Boat Info
44DA
Engines
Cummins QSC 8.3's
So the coolmatic refrigerator in the salon wont work when i just have the battery's on. IT works fine on 110 volts but not 12 volts. So i call Waeco and they tell me its a 12 volt unit. Im like that doesnt make any sense. USusally it doesnt work in 110 volts . So i ask for a wiring diagram. Sorry we dont have one. I ask if the unit has a condensor fan that might cycle on condensor temperature. They respond they dont know. Is there a tech i can talk to ? U are talking to him . I was like excuse me ? So they tell me the unit is discontinued and they therefore dont support it . Boats 6 years old and I know it was used in atleast 07 . So anyway WTF ? The refrigerator is getting 12 volts . the lights work , I hear the compressor run, then stop, then run again. About 3 min cycles ( in dc mode ) I know its not cycling on temperature . If i turn on the 110 v breaker in the panel the refrig runs fine . So what in world would stop a 12 volt DC refrigerator from working in 12 volt dc mode when it works fine in 110 mode . the inverter is simply turing the 110 to 12 volts anyway .
Makes no sense. YEs i have to pull out the refrig , but the cabient laminant glue is stuck to the refrigerator frame. Im afraid when i try and pull it out im going to delaminate my cabient. So im trying to figure out whats wrong before I open up a mess. ugh !

Any thoughts ?

Thanx

Rob
 
"I ask if the unit has a condensor fan that might cycle on condensor temperature. They respond they dont know. Is there a tech i can talk to ? U are talking to him . I was like excuse me ? So they tell me the unit is discontinued and they therefore dont support it"

Wow! Unbelievable. How do these outfits stay in business?

Let me start by saying I spent a great many years in the refrigeration business......but sadly I'm just not real familiar with the operation of these fridges on boats since I've just never had occassion to work on any of them over the years.

Since we now have our own boat and I'm spending alot of time around our marina.....and a couple of people had fridge problems last year and replaced their fridges.....I've started reading up on these things to gain a better understanding of them. In case I run into problems with mine.

So please bear with me while I scratch my head along with you.

"If i turn on the 110 v breaker in the panel the refrig runs fine ."

Well at least that's good news. Your compressor sounds fine...and your temp control sounds fine if it's cycling on temp as it should.

The puzzler is the 3 minute "short cycling" on DC?

My initial suspicion is that there is something goofy going on with the inverter that's supposed to convert your 12V DC to 110V AC to run that compressor. Are you getting enough DC power into it? And is it putting out the proper AC power to run that fridge?

It sounds to me like you have no alternative but to pull it out so you....or some refrig tech...or electrician....can gain access to the guts of it and try to troubleshoot it.

I'd want to put a meter on a few things when it's in 12V mode. I'd want to know that you're getting a full 110V to the compressor from the inverter. I'm wondering if you're getting a low voltage there...possibly causing the amperage draw to be a little high....in turn causing the compressor overload to trip? After a few minutes...the overload resets itself and it restarts itself....and repeats that 3 minute "short cycle".

Wish I could help more but unfortunately....without being there and actually seeing it and troubleshooting it.......I'm afraid you may have to find a good fridge tech to help you out.

Good luck.
 
Vet,
The compressor is 12 volt compressor. Thats why it doesnt make sense. The frig runs off the house batteries and the voltage is fine under load. I called Waeco back again and its just waste of time . I was hoping someone else would be more helpful, no such luck.

Rob
 
The compressor is 12 volt compressor.

You absolutely sure about this? How do you know this. If it's a 12 volt compressor....how does it run on 110V a/c when on shore power?

THIS statement...is what makes me doubt that:

If i turn on the 110 v breaker in the panel the refrig runs fine .

Everything I've read about these things said they were 110V compressors.....built in inverters to change your 12V DC to the 110V ac needed to run that compressor.

Since the manufacturer seems to be of no use to you...best I can suggest is find a good fridge tech to look at it....confirm what you have there and troubleshoot it to find out what's going on. Wish you were here at my Club.

Good luck.
 
Its quite simple, it works the other way around. The house batteries run the whole unit on 12V DC and when on AC there is an AC to DC power supply that steps the 110 down to 12.

To explain why it works on 110 and not 12, there will be a fuse in series with the DC going into the unit from the house batteries. Probably in the back of the fridge. It could also be faulty 12V breaker on the house power panel.
 
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Hate to disagree with you there testlab....but with all due respect I don't think it is "quite that simple"....and I'm not sure you've convinced me. Yet. :)

In everything I've read about them thus far.....nothing talked about there being a 12V compressor in these fridges

there is an AC to DC power supply that steps the 110 down to 12.

Everything I've read thus far indicates that the compressor is 110V alternating current only.

110V ac cannot be "stepped down" to 12V dc

From Wikpedia:

A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC),

Also from Wikpedia:

A power inverter, or inverter, is an electrical device that changes direct current (DC) to alternating current (AC);[SUP][1][/SUP] the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits.

Everything I've read thus far indicated that an inverter is used to run that 110V compressor changing the 12V dc to 110V ac when on battery power.

If anyone can point me to a link somewhere that is contrary to that I'd appreciate it.
 
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Almost every manufacturer including Waeco use the Danfoss compressor which is 12/24 volt DC as standard (except for Norcold junk). When the optional dual voltage AC/DC option is ordered there is an AC to DC convertor installed. I have to 100% agree with testlab that if it runs on 110vac the fridge is probably ok. The two possibilities are that 12vdc is not getting to the fridge (fuse, switch, wiring issue), or that the fridge is not switching over to 12vdc power. When AC is supplied it is set up to be the preferred power source and automatically switches back to 12vdc when removed. There is also a low voltage cut out and your battery may be hovering on the edge of that voltage. I do have wiring and trouble shooting info that I can email.
 
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Rob,

I think it's going to be very hard or impossible to tackle this without pulling the unit out. I understand what you described and my first thought was also lack of full 12VDC power on the inverter side. From your description "IT works fine on 110 volts but not 12 volts" I would focus on analyzing the output difference when you turn on 110VAC vs. 12VDC, but I don't think you'll be abdle to do it with unit in place. I've pulled out few fridges on the boat and it usually not bad at all. Just take your time and do it carefully and you might be able to find the answer without their "tech support guru".
 
I tried to attach some files that appear to be to large. Let me know if you need manuals emailed.

Rick
 
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So I finally pull the fridge and replace the A/c -Dc switch on the fridge. The thought was the switch would not fully switching between 110volts and 12 volts.
Nope fridge short cycles. So I just gave up and run the fridge of the genset.
Well im embarassed to say it was one bad battery in my house bank that was causing my issue. Last week after being on the hook for a few hrs I couldnt start my port motor. Came back to the dock Checked my connectionsall were tight. Marina checked the batteries and sure enough one battery tested bad. Installed a new battery and on a hunch ran the fridge and it worked flawlessly. So the entire time I had voltage issue like some had posted. Since the boat started and it always showed 12.5 - 13 volts. i just didnt give it too much thought. Well now i know . Thanx guys for all ur help.


Rob
 
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