Frigidaire fghb2866pf9a defrost problem.

[Soso]

 I have a Frigidaire fghb2866pf9a with a Defrost problem. I have been working on. The freezer is on the bottom. About every two or three months you have to put it into manual defrost and get the blow dryer out and defrost it manually. I have changed the Control board and the bi metal with no differences in the way it defrosts. I have shown up to work on it and it one time was right in the middle of a defrost cycle. Its like it has a mind of its own. I checked the seal on the drawer seems fine. I have wondered if the customer is leaving the drawer opened at times letting air or moisture in. They say they are not leaving it opened.

Any Ideas or help would be great. Thanks 

[Tim M]

If customer is leaving door open, you will likely see fuzzier rime ice on the ceiling of the freezer.  Do you?

Is drain under defroster freezing up?  If so, does this one have a duck bill on the drain that needs to be updated, or does it need a wire down the drain to keep it from freezing?

[Tim M]

Have a look at this for rime ice:

http://fixitnow.com/wp/2012/12/08/refrigerator-diagnosis-and-repair-ice-frost-and-condensation/

[Soso]

Hey Tim Thank you.

Every time I get their at the customers they have the freezer section cleaned out and I have not noticed rime ice. If there is it is not as bad as i am seeing in the video you posted. I will ask them to leave it next time so I can assess it better.

As for the drain, no water coming out on the floor of the freezer from a plugged drain.

I will look at the ice pattern and surrounding area better to see if I can pick up on anything. 

Thanks, again

[16345Ed]

Did you test evap thermistor?

Part number: 808137001

[Soso]

 Sorry I have been out of town.

I will test and replace if needed thank you.

 

[Fixitrightthefirsttime]

I’m having the same issue where the defrost system is failing, but heater can be activated in diagnostic mode. I have replaced the defrost thermostat and control board with no improvement. I have just replaced the control board for the second time and am waiting to see the results. I wish I had seen this earlier about the evap thermistor  p/n 808137001. Should I be replacing that as well? Could that really be causing the defrost process not to activate? Thank you

[Tim M]

Probably you should start your own thread for this.

Have you tested the parts you have replaced before replacing them?

Have you ruled out user error?  The customer could be leaving the drawer open.  Lots of times they have so much junk in it that it will not close, though they will swear it did.