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Hi,I have a 2013 Norcold nr 751...

Heat_Wave
Guest Contributor

Hi,

I have a 2013 Norcold nr 751 refrigerator that was working last year when I winterized it. I turned the thermostat knob clockwise too far past 1 and I believe I broke it because frig now won't turn on. It's getting electricity because the light turns on but the compressor won't start up. Any suggestions so that I can avoid buying a new marine frig? 

4 REPLIES 4

wingless
Rising Contributor
Welcome to the forum.

The Norcold NR751 has a Danfoss BD35 compressor.

https://norcold.com/product/norcold-nr751-ac-dc-refrigerator/

It is "easy" to discover why the compressor isn't happy by attaching an LED / resistor and reading the flashing error codes.

On mine, I now have an LED permanently attached.

Heat_Wave
Guest Contributor
Do you suggest a type of LED/resistor? I have never heard of one.

wingless
Rising Contributor
The Danfoss BD35 / BD50F compressor / controller may sink up to 10mA on the D connector terminal.

As an example, this red LED has 2.1V of forward voltage drop. That ~2V is typical for these leaded red LED devices.

https://www.cree.com/led-components/media/documents/C503B-RAS-RAN-AAS-AAN-RBS-RBN-ABS-ABN-RCS-RCN-ACS-ACN-1079.pdf

Assume that the DC voltage supplying the refrigerator is 14V. So, 14V-2.1V = 11.9V. Ohms law says V=I * R, so the resistor R = V / I. Assume 5mA of current. R = 11.9V / 0.005A = 2,280 Ohms, consuming about 60mW, so any ¼W resistor would be fine. Any resistor in this range would be fine, doesn't need to be exactly this value, plenty of margin / range for this resistor.

wingless
Rising Contributor
Here are images of mine:

https://live.staticflickr.com/65535/47943257261_382cf2c271_c.jpg

https://live.staticflickr.com/65535/47943238838_23186994ae_c.jpg

https://live.staticflickr.com/65535/47943223907_46ef97321b_c.jpg