Refrigerators not Working

[argus1]

Both my cockpit and cabin refrigerators stopped working. Boat is a 2011 330/350 Sundancer. I turned on every breaker on the Distribution Panel and made sure that the breaker (next to the battery switches) for the cockpit refrigerator was not tripped. The refrigerators will not run on battery power, generator or on shore power. When on shore power the courtesy light inside the cabin refrigerator flickers. What could cause both refrigerators to go out at the same time?

 

[bobeast]

Rather than attempt to solve it through deduction, I would concentrate on one refrigerator (the one with the easiest access). Ignore the other one and troubleshoot the one you are focusing on. Power and ground is really all it requires to run on 12vdc. Once you find out what is wrong with that one, the same issue may or may not plague the other.

The temptation is to assume a common problem, but focussing on only common pathologies can prevent a useful diagnosis and make your head explode.

 

[argus1]

Rather than attempt to solve it through deduction, I would concentrate on one refrigerator (the one with the easiest access). Ignore the other one and troubleshoot the one you are focusing on. Power and ground is really all it requires to run on 12vdc. Once you find out what is wrong with that one, the same issue may or may not plague the other.

The temptation is to assume a common problem, but focussing on only common pathologies can prevent a useful diagnosis and make your head explode.

Makes a lot sense.

 

[Korkie]

Ground Fault tripped?

 

[argus1]

Reading the manual - it appears that the first place to start is to check the boat’s batteries a strong enough to run the refrigerators.

 

[trflgrl]

Batteries were my first thought--a refrigerator is a HUGE power draw, so low batteries just can't do the job. However, if a fridge is dual power and wired properly, it should bypass the batteries completely when you're on shore power. Have you confirmed what you have and how they're wired? If by some chance a fridge is 12v only--or its AC connection is faulty/has failed--low batteries may one of multiple problems. Check for inline fuses, too, most likely in a very hard to reach place. I doubt we have the same model fridge, but that was an issue for us once. I had to pull the fridge far enough out of its cubby to find it; the fuse holder had become worn and no longer kept a tight connection.

 

[bbwhitejr]

Marine refrigerators are designed to cut off when the batteries reach a certain low point of about 11.4v. Are you sure they both are hooked up to 110v? I have one refrigerator that runs only on 12v. I turned the battery charger off one time and accidently forgot to cut it back on before leaving the boat. It pulled batteries to a certain point and then shut down.

Bennett

 

[km1125]

The flickering light is a clue and could lean to the low battery issue suggested or poor connections. That light should just be on or off. If you can't make that work correctly, don't even think the compressor would be able to work.

 

[argus1]

The Dometic refrigerators operates on 12v DC or 24v DC. It uses a rectifier to convert from 100 – 240v to either 12 or 24 v DC. The rectifier senses when it is connected to shore power and rectifier automatically switches from battery to shore power. Since it is both refrigerators not working, I am wondering if they both share the same rectifier that is hidden behind one of the many panels.

 

[Dani-Lu]

Ground Fault tripped?

Assuming you are on shore power, check the GFI receptacle in your head? Both AC’s are probably on the same AC circuit.

 

[Skybolt]

The Dometic refrigerators operates on 12v DC or 24v DC. It uses a rectifier to convert from 100 – 240v to either 12 or 24 v DC. The rectifier senses when it is connected to shore power and rectifier automatically switches from battery to shore power. Since it is both refrigerators not working, I am wondering if they both share the same rectifier that is hidden behind one of the many panels.

No there is a black box (power converter) for each one. You need to pull the frige and check the voltages. Assuming that the inside thermostat is on highest cold setting.

 

[Dani-Lu]

No there is a black box (power converter) for each one. You need to pull the frige and check the voltages. Assuming that the inside thermostat is on highest cold setting.

I thoughts both his frigs were AC and DC? If they are AC/DC, they work on 120v AC or 12v dc. If this is the case, troubleshoot the AC side first. If both frigs went at the same time, it is probably a power issue. Highly unlikely for them to go bad at same time.

 

[argus1]

No there is a black box (power converter) for each one. You need to pull the frige and check the voltages. Assuming that the inside thermostat is on highest cold setting.

Not Correct - The refrigerator on my 2011 350 Sundancer are 12/24 DC, not 110/240 AC. The Dometic manual for the CRX refrigerators that are installed, clearly state that these refrigerators must be connected 12 V or a 24 V DC voltage supply and can operate on AC current when a rectifier is used. The rectifier transforms an input voltage of 100–240V AC to 24V DC, so that the refrigerator can be connected to an AC power supply.

The manual also states that: You can connect the refrigerator to 100 – 240 Vw AC power if you use the MPS35 rectifier (accessory). The MPS35 rectifier features a priority circuit which conserves the battery connected. When a 100 – 240 Vw mains connection is used, the rectifier automatically switches from battery to mains operation. When disconnected from the 100 – 240 Vw mains supply, the rectifier automatically switches back to battery operation. Mains operation via the rectifier always takes priority over battery operation. To protect the battery, the refrigerator switches off automatically if the voltage is battery voltage insufficient. The cut-off voltage on a 12v system is 10.4 V and the cut-in voltage is 11.7 V.

The trouble shooting guide indicates weak batteries must be considered when the refrigerator is not operating. My batteries are 4-years old. I will do a voltage test on the batteries later this afternoon and replace batteries if needed. I really think that the problem is not with the refrigerators themselves since both are not working but rather in the electrical supply going to the refrigerators.

 

[Skybolt]

Not Correct - The refrigerator on my 2011 350 Sundancer are 12/24 DC, not 110/240 AC. The Dometic manual for the CRX refrigerators that are installed, clearly state that these refrigerators must be connected 12 V or a 24 V DC voltage supply and can operate on AC current when a rectifier is used. The rectifier transforms an input voltage of 100–240V AC to 24V DC, so that the refrigerator can be connected to an AC power supply.

The manual also states that: You can connect the refrigerator to 100 – 240 Vw AC power if you use the MPS35 rectifier (accessory). The MPS35 rectifier features a priority circuit which conserves the battery connected. When a 100 – 240 Vw mains connection is used, the rectifier automatically switches from battery to mains operation. When disconnected from the 100 – 240 Vw mains supply, the rectifier automatically switches back to battery operation. Mains operation via the rectifier always takes priority over battery operation. To protect the battery, the refrigerator switches off automatically if the voltage is battery voltage insufficient. The cut-off voltage on a 12v system is 10.4 V and the cut-in voltage is 11.7 V.

The trouble shooting guide indicates weak batteries must be considered when the refrigerator is not operating. My batteries are 4-years old. I will do a voltage test on the batteries later this afternoon and replace batteries if needed. I really think that the problem is not with the refrigerators themselves since both are not working but rather in the electrical supply going to the refrigerators.

So most of the refrig's on boats have a Dometic 12v DC compressor. Then there is a converter box that switches between AC and DC. When on AC it switches to the internal power supply and converts the 120v AC to 12vDC, when The AC is not present the box switches over to the 12v leads connected to the house battery. That is how any refrigerator/freezer that supports running on 12v DC and 120v AC works. Whether it is an internal circuit that does the work or an external "black box" that does it, something must decide which power input to use. Not all refrigerators still have or came with that power converter. If there is a DC breaker and an ac breaker for the frig, then it works this way.

Your interpretation of the manuals description isn't any different than what I just described. Sorry, I didn't want to write a book on the finer details as trouble shooting will still only be done by testing voltages, unless you are able to do component level repair of that circuit.

 

[argus1]

This is what I think the problem may that the resting charge of my both my battery banks is only 10.8V. It could have been even lower but I started the boat while it was connected to shore power and let the engines run for awhile. It is my understanding that a resting battery charge should be 12.8V and 13.4 when the engine is running.

I purchased new AGM batteries from Sam's Club in January 2019; which makes the batteries 3-years-old now. My memory is telling that 3-4 years is lifespan of a marine battery.

 

[Korkie]

Questions: Do all of your other ac appliances operate properly. Air conditioner, hot water heater, stove, microwave, etc. When you turn them on can you see the amperage gauge go higher on the ac side of your electrical panel?

On the 12vdc side, is everything else other than the fridges working properly. Are your lights bright, does your windlass function (properly) or is it struggling, turn stuff on independently and in groups to see if you system handles the load.

 

[Chris-380]

This is what I think the problem may that the resting charge of my both my battery banks is only 10.8V. It could have been even lower but I started the boat while it was connected to shore power and let the engines run for awhile. It is my understanding that a resting battery charge should be 12.8V and 13.4 when the engine is running.

I purchased new AGM batteries from Sam's Club in January 2019; which makes the batteries 3-years-old now. My memory is telling that 3-4 years is lifespan of a marine battery.

AGM's should be good after 3 years unless they were abused. regular marine batteries i can see that being an issue

 

[km1125]

This is what I think the problem may that the resting charge of my both my battery banks is only 10.8V. It could have been even lower but I started the boat while it was connected to shore power and let the engines run for awhile. It is my understanding that a resting battery charge should be 12.8V and 13.4 when the engine is running.

I purchased new AGM batteries from Sam's Club in January 2019; which makes the batteries 3-years-old now. My memory is telling that 3-4 years is lifespan of a marine battery.

A resting voltage of only 10.8V is essentially a "dead" battery. You need to understand how they got that low. As noted above, I agree with the statement that "AGMs (or really any lead-acid battery) should be good after 3 years unless they were abused". Leaving any lead-acid battery in a discharged state is "abuse" and will certainly cause them a shortened lifespan.

 

[argus1]

So most of the refrig's on boats have a Dometic 12v DC compressor. Then there is a converter box that switches between AC and DC. When on AC it switches to the internal power supply and converts the 120v AC to 12vDC, when The AC is not present the box switches over to the 12v leads connected to the house battery. That is how any refrigerator/freezer that supports running on 12v DC and 120v AC works. Whether it is an internal circuit that does the work or an external "black box" that does it, something must decide which power input to use. Not all refrigerators still have or came with that power converter. If there is a DC breaker and an ac breaker for the frig, then it works this way.

Your interpretation of the manuals description isn't any different than what I just described. Sorry, I didn't want to write a book on the finer details as trouble shooting will still only be done by testing voltages, unless you are able to do component level repair of that circuit.

Sorry, I misread your post. I do agree with what you are saying.

 

[argus1]

A resting voltage of only 10.8V is essentially a "dead" battery. You need to understand how they got that low. As noted above, I agree with the statement that "AGMs (or really any lead-acid battery) should be good after 3 years unless they were abused". Leaving any lead-acid battery in a discharged state is "abuse" and will certainly cause them a shortened lifespan.

There could have been a long power outage that caused the refrigerator to automatically switch from shore power to battery power; in the process draining the batteries which would also cause the refrigerators to go into protection mode. What I understand that the refrigerators must sense that there is sufficient battery power before they operate again. I always keep the batteries on the battery charger. However, the heat/humidity here in Florida has a disastrous effect on batteries and everything else on the boat. 3 to 4 years is what I am told that should expect from a well maintained battery here on the Gulf Coast.