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HI WELCOME TO JUST ANSWER.I WILL BE ASSISTING YOU WITH YOUR QUESTION TODAY. YOU HAVE TO CHECK THE DEFROST THERMOSTAT WHILE THE THERMOSTAT IS STILL CONNECTED TO THE COIL AND THE COILS ARE FROSTED. YOU SHOULD GET A READING WITH A OHM METER IF ITS GOOD, NO READING ITS BAD. CAN YOU CHECK THAT AND ELIMINATE THAT POSSIBILITY.
Ah, I've already pulled the thermostat out of the loop. I couldnt figure out where to put my ohm meter probes when it was connected in the circuit...
(I'm actually using a multimeter, though I expect that doesn't matter.)
I've clipped the thermostat back onto the copper pipe feeding the coil (where it was before I removed it, more or less.)
The wires are bared, and not in the circuit anymore.
I'll take a resistance reading in a few minutes, after the thermostat cools down from room temperature...
OK, LET ME KNOW.
Even cold, my multimeter shows @ 140 K Ohms of resistance across the thermostat. That seems high. There's more resistance when the thermostat is warm. But that seems screwy to me.
I've pulled the thermostat out of the circuit and bridged the circuit around where the thermostat used to sit. I figure this will let the defrost heater be controlled completely by the defrost timer, without the (defective?) thermostat getting in the way. This will give me more defrost than I need, probably, but will at least keep the coils from getting so caked with ice that the fridge goes warm on me.
Of course , could be that I'm making matters worse... :)
AS THE THERMOSTAT GETS COLDER THERE IS LESS RESISTANCE, THIS IS SO WHEN ITS COLD ENOUGH AND THE DEFROST CONTROL CALLS FOR DEFROST THE HEATER CAN COME ON, ITS IN SERIES WITH THERMOSTAT.
That makes sense. But I suspect that 140k ohms is too much resistance for the heater to warm?
YES AFTER A FEW MORE MINUTES DOES THE RESISTANCE GET LESS?
It's still high. In the K Ohm range...
It's been clipped to the coils for almost 20 minutes. The body of the thermostat is @ 21 degrees F.
One of several numbers stamped on the body of the thermostat says 43F, which I assume should be the calibrated point at which the thermostat switches on/off.
OK THAN PROBABLY ITS THE THERMOSTAT, THE ONLY OTHER PART IT COULD BE IS THE DEFROST CONTROLER WHICH IS A CIRCUIT BOARD UP IN THE CONTROL PANEL WHICH IS A LOT HARDER TO GET TO. OR THE HEATER WHICH USUALLY DOESNT BURN OUT , BUT YOU CAN CHECK IT IF YOU WANT TO. DO YOU WANT THE PART NUMBER FOR THE THERMOSTAT?
As an additional point of information, when I was wiring the power back to the defrost heater, after pulling the thermostat out of the circuit, I got zapped. Which might mean that power is getting sent to the heater by the defrost timer.
Yes, would love the part number for the thermostat. Do these things go bad, in your experience?
YES THEY DO PRETTY OFTEN.
PLEASE UNPLUG THE REFRIGERATOR WHILE WORKING ON IT, DONT WANT YOU TO GET ZAPPED.
Neither does the wife.
STAND BY A MINUTE.
I've seen buzz online that the defrost timer boards go bad pretty often too. You think it makes sense to order both parts, and ship the timer board back if the thermostat fixes the issue?
Also, does it make sense to leave the power feed from the defrost controller to the heater connected without the thermostat in line?
OK SORRY IT TOOK SO LONG, THE THERMOSTAT ONLY COMES AS PART OF THE HEATER YOU CAN NOT GET IT SEPERATELY. CLICK HERE FOR PART
YES GETTING BOTH PARTS MAKES SENSE THEY HAVE A LOT OF TROUBLE WITH THE DEFROST CONTROLERS ALSO. I WOULD NOT WIRE THE CONTROLER STRAIGHT TO THE HEATER WITHOUT THE DEFROST THERMOSTAT IN THE LINE.
I guess that's why it wasn't obvious how to pull the thermostat out on it's own: they're wired together as a single unit.The part you show doesn't look like the part I pulled out. Does that matter?
THIS IS THE PART NUMBER FOR THE DEFROST CONTROL CIRCUIT BOARD.CLICK HERE
WHAT DOES THE PART LOOK LIKE YOU PULLED OUT?
thanks for that. There's a black plastic sheath on the thermostat pictured in the link above... The thermostat I pulled out of the fridge has a clip where that picture shows the black plastic sheath.
(I love repair clinic's return policy.)
IT SHOULD NOT MATTER ITS THE PART FOR YOUR MODEL. YEAH THERE RETURN POLICY IS GREAT AND THERE SHIPMENT FAST.
the part I pulled out looks like this: http://www.repairclinic.com/PartDetail/Defrost-Thermostat/61005254/791286
Without the spade connectors, of course...
THE LINK DID NOTHING WHEN I CLICKED ON IT.
COPY THE LINK AND PASTE IT IN THE COMMENTS AND I WILL TAKE A LOOK AT IT.
Let me try again: CLICK HERE
DID YOU FIND THAT FOR YOUR MODEL NUMBER?
In any event, I'll order up these parts and see if that doesn't do the trick. I assume I can get the heater in without removing the coils and mucking around with the refridgerant. Right?
YES YOU SHOULD NOT HAVE TO MOVE THE COILS MUCH IF ANY.
Cool... I'll order the heater/defroster and the defrost controller board you pointed to. I didn't find a stand alone thermostat that matched the specs on the unit I pulled out, or my fridge model.
One last question... Is there a mechanism that controls airflow from the freezer to the fridge, other than the fan above the coils? The fridge cools unevenly, and not so well (even when the coils are clear.) I wonder if there's a damper up in the top of the fridge that I need to worry about...
YES THERE IS A DAMPER, BUT I WOULD CHECK THE DOOR GASKET AND MAKE SURE THE DOOR IS CLOSING GOOD WITH NO SMALL OPEN SPOTS FIRST.
Any tips on how to do that?
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OH JUST FEEL AROUND THE DOOR SLOWLY AND MAKE SURE YOU DONT FEEL ANY COLD AIR ESCAPING, VISUALLY LOOK AT IT AND DONT FORGET TO LOOK AT THE VERY BOTTOM WHERE IT USUALLY HAPPENS.