my fridge is cold but wont shut off? anyone work on fridges?

[drifter]

I got a older used fridge for my shop probably from the 1980's its a Kenmore coldspot model C106
plugged it in blew warm air looked in the back and the compressor had fitting to fill it I took off the cap and the valve was leaking so I thought ok that's why its blowing warm air changed the sharder valve and put 2 can of free on in its crazy cold I have a thermometer in the fridge and it will get down to 30F

Problem is it wont shut off ever I changed the cold control thermostat in the fridge with 3 used ones it makes no difference if its on the coldest setting just keeps running all nite long I even changed the relay looking start switch on the compressor still keeps running WHY wont it shut off?

The defroster/heater works I seen it kick on and then the compressor & fan stopped but once that was done it was back on again

[Kevin Johnson]

http://bbs.homeshopmachinist.net/archiv ... 56035.html

[drifter]

Thankyou for the reply but still no luck I let alittle Freon out because the suction line was sweating now its not and the frezzer temp is -10 so I think im in the ball park there now the system was pretty much empty when I got it and I added two of the small cans that you would use on a car system it says its compatible with 134 so I thought it should work this fridge was r12 im sure because its so old but I still cant figure out why it will not shut off and the cold control has no effect on the temp setting at all it will shut the fridge off but when its on even in the lowest setting its full tilt cold

[drifter]

question on the cold control thermostat the way I read about them is when the fridge is warmer inside the switch is closed and as the fridge cools the switch opens I have 4 used ones here and all are making the compressor and fans stay on

[Kevin Johnson]

Just a WAG but from reading the other thread you might try bleeding off a bit more Freon.

[user-23911]

It's the thermostat that breaks the circuit when it gets cold enough.
You've got to have the right thermostat, it's got to be fitted right and it's got to be a working thermostat.
I've fixed lots of them.

[JoePorting]

Watch your power bill. Some old fridges will use $20 to $30 per month in electricity. Your probably better off just buying a new $500 fridge.

[BCjohnny]

IANAE, but from what you've said ..... although the charge qty is important (as is keeping air out), almost regardless of anything else once it's down to temperature it sounds likely a control problem, which suggests stat or control setting dial/circuit.

Either will allow the system to keep running continually if faulty, so if you're sure the stats you've used are matched, the next thing I'd be looking at is the setting dial, and then the entire control circuit (wiring etc). Resistive and open circuits would be the main culprits, maybe something as simple as a wire off or corroded joint.

Generic unmatched value stats can get you chasing your tail (as with anything). Freezer stats?

If you can obtain the correct resistance value for the stat that should be fitted to the appliance, put the ones you've tried across the Ohms setting on a multimeter and compare the values to eliminate that as an issue.

[Kevin Johnson]

Watch your power bill. Some old fridges will use $20 to $30 per month in electricity. Your probably better off just buying a new $500 fridge.

Exactly this -- we had an older fridge running in the garage and replaced it with a used but newer and more efficient one and it paid for itself in under one year.

[drifter]

Well last night I put another used cold control thermostat in and this morning when I came in it was off I was shocked its for now working like it should thankyou for the guys that took the time to give me advice