Refrigerator fire!

[tce001]

I've recently purchased a Jeanneau SO 40 DS with a Isotherm BD35 fridge. When we took delivery, the fridge was not working, and we found out that the red Isotherm ASU control box was fried. Black soot all over the inside and no action on the compressor when we applied power.

We replaced the red asu box with a new one, and it's been working fine for the last 3 months. We turned power off to the fridge for a weekend to defrost the holding plate, and when we turned it back on, it was struggling to stay on and eventually would trip the breaker.

When I started to take it apart to put the LED across the black controller box, I found that the ASU was fried again.

Any ideas on what is happening here?

Has anyone removed this controller and routed the thermostat to the black control box directly?

[Typhoon]

Yes yes , get rid of that ASU and wire your thermostat directly to the Danfoss control module . If you must speed your compressor up , do it yourself with a resistor.

I have a customer that has the same set up on three machines , constant failures , he is replacing all his systems with mine .

This is the wiring diagram for the BD35 Danfoss compressor

http://files.danfoss.com/TechnicalIn...cei100b602.pdf

Regards John.

[Richard Kollmann]

I would first suspect a shorted Danfoss control module and a, not so good, circuit breaker. What is the amperage rating of breaker?

After you confirm that circuit breaker is no more than 15 amps. I would turn breaker OFF and remove the ASU and place a jumper wire between Danfoss module thermostat electrical terminals C and T.

Connect power wires with correct polarity to Danfoss control module. If this unit has a seawater pump condenser cooling system disconnect the pump relay and any wire connected to Module terminal F.

Final test to check condition of module turn on circuit breaker. If breaker trips module is shorted inside and not repairable. If compressor is now running it will be at minimum 2000 Rpm without condenser cooling. If fan cooled reconnect fan ground wire to F terminal. If water pump cooled reconnect water pump and check pump amperage as this may be reason ASU failed.

I have new three pin control modules but not to be used with ASU gadgets if you want to barrow one to test your system at no charge even if my module is destroyed.. Email me I now live on Merritt Island.

[1affiah]

You may also want to clean the airways to the fan and check it for operation and direction of flow. The factory supplied fans are junk, replace with a Noctua. Airflow is vital to the operation of these to remove the heat.

[tce001]

Originally Posted by ColdEh Marine

Yes yes , get rid of that ASU and wire your thermostat directly to the Danfoss control module . If you must speed your compressor up , do it yourself with a resistor.

I have a customer that has the same set up on three machines , constant failures , he is replacing all his systems with mine .

This is the wiring diagram for the BD35 Danfoss compressor

http://files.danfoss.com/TechnicalIn...cei100b602.pdf

Regards John.

On the ASU, the thermostat comes in on the upper phone plug, I believe. Is there a wiring diagram showing which wires to connect to the Danfoss control module?

[Typhoon]

Originally Posted by tce001

On the ASU, the thermostat comes in on the upper phone plug, I believe. Is there a wiring diagram showing which wires to connect to the Danfoss control module?

Thats right ..... your controller looks like this ?

If you place a jumper across the c and t terminals , and the compressor runs and cools as normal this will confirm that the problem is in the control circuits of the ASU system.

It could be in the control head or the part at the module , you may be best served to remove all of this and use a mechanical thermostat like this one .

RPARTS.COM - Danfoss KP-73

http://coastalclimatecontrol.com/ind...echanical.html

This one is cheaper but will work fine.

Regards John

[tce001]

That is the controller we have.

I've put the jumper across and it seems to be running fine. How long is it safe to run it in this configuration? Could I turn it off for 10 minutes every hour until it gets cold, and then run it 20 min/ hour?

I was planning to be out this weekend, and would rather not fill up with ice if I can avoid it.

[Richard Kollmann]

Originally Posted by tce001

That is the controller we have.

I've put the jumper across and it seems to be running fine. How long is it safe to run it in this configuration? Could I turn it off for 10 minutes every hour until it gets cold, and then run it 20 min/ hour?

I was planning to be out this weekend, and would rather not fill up with ice if I can avoid it.

You did not answer questions about water or air cooling. If air cooled and condenser fan is running let compressor run as long as you need it.

[tce001]

It has water cooling. I've attached the fan leads normal on the ASU to the + and F and it seems to be running the water pump ok, at least for a while. After about 10 - 15 min, the pump turns off. I'm not sure if that's normal fan behavior or not.

Thanks for all the help!

[Richard Kollmann]

Originally Posted by tce001

It has water cooling. I've attached the fan leads normal on the ASU to the + and F and it seems to be running the water pump ok, at least for a while. After about 10 - 15 min, the pump turns off. I'm not sure if that's normal fan behavior or not.

Thanks for all the help!

If compressor is running pump must run to cool condenser.

[Typhoon]

There should also be a little black box powering the pump. This is a voltage regulator . the pumps on these machines run at a different voltage then the rest of the system . These little regulators get hot as well and are prone to failures. The regulator may be telling the danfoss controller there is a problem with the fan once it warms up and tripping a code shutting down the compressor. . This is a tough one , you cant just change out the pump on these units with any other pump because the condenser is built into it and replacing all the electronics on these systems is very expensive. I have a customer with all the same problems as your , he has three of these machines on his boat , his solution was to replace the entire system . This was a factory installed system that came with the boat. So I don't know what to tell you , you may be better of to just remove the system completely and start over with a simple air cooled system . It may be cheaper then trying to get that system running reliably again. If your system had been an air cooled ASU system a simple thermostat change would have fixed you up . Maybe Richard has another solution.

Regards John

[tce001]

Thanks for your help, John. We do have the voltage regulator on the pump. I'm running it now with the LED on the Danfoss controller to see if gives me an error code. Hopefully I get find a way to make it work for less than a new unit, as we have a number of other things on the list to get for the "new" boat. But it's a critical piece of gear, so if we have to, we have to.

Thanks again.

[Richard Kollmann]

Any time I see or hear these words “remove the system completely and start over” it is advice from some sales person or another technician from hell. It is true that there is no real profit in repairing small 12 volt refrigeration because there are no two pleasure boat refrigeration systems the same. There is also no guaranty a new replacement system will be trouble free. I find in most cases as tec001 is experiencing the fix will be a simple solution he can do himself.

[tce001]

After the latest test, it looks like the voltage regulator for the water pump is failing. It will run for about 15 minutes and then cut out. It's not hot, but if you squeeze the sides of it, the pump will come back on for some random amount of time, then go out again. You can do this a few times before you have to turn it off for a bit to get it working again. Sounds like the heat buildup is causing a gap to expand and break the circuit.

The next question is, is there something special about this voltage regulator? Isotherm-parts.com has it for $216, which seems kind of high. "normal" voltage regulators run around $20 or so. Here's one from amazon: https://www.amazon.com/Converter-Adj...ator+12v+to+6v

Does it have some other function?

[Typhoon]

[QUOTE=tce001;2386972]After the latest test, it looks like the voltage regulator for the water pump is failing. It will run for about 15 minutes and then cut out. It's not hot, but if you squeeze the sides of it, the pump will come back on for some random amount of time, then go out again. You can do this a few times before you have to turn it off for a bit to get it working again. Sounds like the heat buildup is causing a gap to expand and break the circuit.

The next question is, is there something special about this voltage regulator? Isotherm-parts.com has it for $216, which seems kind of high. "normal" voltage regulators run around $20 or so. Here's one from amazon: https://www.amazon.com/Converter-Adj...ator+12v+to+6v

Does it have some other function?[/QUOTE

Thanks for the kind words Richard.

I kind of suspected that the voltage regulator would be one of your problems . I know parts from Isotherm are very expensive . I do recall a client with your system telling me that the pumps run at 5 volts . He discovered this after replacing three of them . You could try a 10 dollar regulator from eBay and see if it works . I'm sure the pump takes very low current . If it works buy a few for spares and install that mechanical thermostat . You should be good to go . Restoring the electronics is really expensive.

Regards John