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Bryan
Bryan, Home Appliance Technician
Category: Appliance
Satisfied Customers: 12156
Experience:  15 yrs. experience as a certified appliance technician.
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211RFD refrigerator; freezer seems to go into defrost cycle

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211RFD refrigerator; freezer seems to go into defrost cycle and temp at center of freezer compartment rises from ~-12F to as high as +50F. Evap. fan stays off during this period. When it "decides" to freeze again, it cools rapidly so gas cycle seems OK. This "cycle" seems to start ~ 8 AM and goes on for maybe 2 hours. I am taking time/temp data now. I see that the timer and a "defrost terminator" are available as replacement parts. The "terminator" seems to be a reasonable possibility. I don't have a service manual or diagrams. What say?
its deffinetly one or the other, 1 defrost timer is sticking and running slow, Part 7538672 Part(NNN) NNN-NNNN width= the defrost thermostat, this could be not sensing the freezer is defrosted and keeps the heater on. I would change them both to be sure, these both fail after a while and need to be replaced anyway, parts should run under $75.00 so its worth it, hope this info is helpful. thanks Bryan
Customer: replied 6 years ago.
OK, so the timer controls the defrost period and the "thermostat" just controls the heater. I just dropped the evap shroud and found the heater isn't working. Can I put this transaction on hold for a bit while I check for power to it and get back to you?
sure , the defrost thermostat is the thing you should be looking at, check for continuity when this thermostat is (cold only) this should have continuity when cold and nione once it warms above 50 degrees, I'll bet its bad, thanks Bryan, p.s. also check heater for continuity although rarer these sometimes fail.
Customer: replied 6 years ago.

(Note: Fan isn't running, even when I push in the door switch. It does run when the freezer is in the cooling mode.)

Thermostat shows continuity at less than 50F (but no ice around it) - Heater shows ~33ohms, but is getting no power.

So, correct me if I'm wrong, the heater thermostat is closed when cold, and breaks power to heater when warm so heater should be getting power now, provided by output of the timer routed through the thermostat. OR does the thermostat control (for instance) a relay which interupts heater power?

Am I correct in the assumption that the defrost cycle is always the same time period, or does the timer stop until the thermostat opens (defrost complete) and then resume operation? Wish I had a schematic!

ok the defrost thermostat sounds good, the heater sounds good, so since theres no relay that runs the heater in this it comes down to the defrost timer, yes the defrost timer is suppose to run at the same time period as long as the thermostat is closed the timer should be running, this defrosts about every 8 hours, you can advance the timer by hand to get to defrost (you will hear it click and the fans should shut off, then test for power to the heater do that and let me know,
Bryan and 2 other Appliance Specialists are ready to help you
Customer: replied 6 years ago.

(The timer has been in the defrost mode while we have been "talking".)

 

I advanced the timer through several cycles and then heard a sizzling noise and saw the heater had come on. Looks like I have tired heater contacts in the timer??

 

One clarification - You said, "as long as the thermostat is closed the timer should be running" - does it stop when the thermostat is "open"?

 

Customer: replied 6 years ago.

Hi Bryan; I guess you are no longer there. I think I got what I needed and thanks!

Barry

sorry I had to go out for a bit, as far as the timer goes it usually deos stay running, I believe you have a bad timer. if you need more help just leave the question open and I keep an eye on it, thanks Bryan
Customer: replied 6 years ago.
OK & thanks again. I did "accept" your advice - did it register ok? I have the timer on order so by Thursday should have an answer.
your welcome, yes the accept is made I believe, thanks and happy holidays, Bryan
Customer: replied 6 years ago.
Just to keep you informed, since I disconnected the defrost thermostat to check continuity and reconnected, disconnected heat element and reconnected and moved the timer around a bit now the steady state freezer temp has risen from ~ -12F to ~ -5F. Go figure!
I believe if the thermostat and the heater check out it has to be the timer, you said the heater was crakling so that mean the heater and thermostat are good, I would change the timer, thanks Bryan

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