Norcold fridge short cycling

[camsaure@aol.com]

According to the paperwork with the Mariner boat it had a model DE828. But now I pulled the fridge and it appears to have been replaced.. The one I have issues with has only one compressor and has CFC free refridgerant 134 A. The label says Sawafuji Model SK-515M,50hz, Lot no 02-1-16. On a bar code label it says DE461 and OIN-0168. It short cycles on both12 volts and 110 volts. I tried disconnecting the cooling fans and nothing changed. I am not sure where the thermostat is located in order to try and hot wire it. Where do I go from here?

[Rocketman]

Try disconnecting the power adapter module and wiring the 12v input direct to the output going to the compressor.
I have had problems in the past with the power adapter module relays and not allowing the unit to run.

[km1125]

QR_BBPOST Try disconnecting the power adapter module and wiring the 12v input direct to the output going to the compressor.
I have had problems in the past with the power adapter module relays and not allowing the unit to run.

You CANNOT do that on these compressors. These are AC compressors. They have a big electromagent surrounding the piston and the AC on the electromagnet causes the piston to oscillate back and forth (and there's springs on each side of the compressor to help). When you are running on DC, the DC actually goes through and inverter to create an AC waveform to run the compressor. The AC voltage on the compressor is between 26 and 40 volts, depending on the model.

[km1125]

QR_BBPOST .... I am not sure where the thermostat is located in order to try and hot wire it. Where do I go from here?

There is a thermostat sensor screwed into the bottom of the evaporator (freezer) on the bottom. If you slide out the drip tray you should be able to see it. It's a thermister. The power supply uses that, along with the variable resister in the "thermostat (the knob where the on/off switch is) to determine the actual temp and the desired temp to know if it needs to activate the compressor or not. You can't just "short it out" to turn it on.

[camsaure@aol.com]

Thankyou for that warning! Do you happen to know which part could be at fault? power supply, thermisistor, or temp control? Also where I could best possibly find replacements?

[camsaure@aol.com]

I think I have low voltage coming out of the power supply to the compressor.

[km1125]

QR_BBPOST I think I have low voltage coming out of the power supply to the compressor.

What did you measure? When you measured, was it with the compressor disconnected or connected?

You should measure both ways... with a load (the compressor) connected and then disconnected. Also measure both ACV and DCV to see what you get (so that's a total of FOUR measurements). Was the compressor warm at all?

I'll look for the documents on that model and see what I have. Might have some of the parts for it too.

[camsaure@aol.com]

I need to get a better voltmeter and check again. I unhooked one wire when I checked it. I guess I need to perform more tests as you suggested. Thanks again.

[km1125]

QR_BBPOST I need to get a better voltmeter and check again. I unhooked one wire when I checked it. I guess I need to perform more tests as you suggested. Thanks again.

I PM'd you a troubleshooting document for the DE461 models. Lots of good info in there. Let us know what you find.

(tried to post the doc here but it would only let me attach picture files).

[camsaure@aol.com]

Sorry, I dont think the attachment went through, I cant find it.