FIXED Subzero refrigerator/freezers 700TCI- Ice buildup

[georgepb]

hard to tell if the fan behind the evap was running or not because all fans stopped as soon as I opened the door or the drawer. I don't think the ice was all gone after defrost. It's been about 3 hours since I restarted the unit and the freezer temp shows -22 degree. Very strange.
I will shutdown the unit tonight and let all ice melt overnight then put the evap cover back before turning it back on. Let it run for two weeks and see what happens to the evap. Will keep you posted. Thanks.

 

[georgepb]

Ice hasn't competely melted so I took another pic. I wonder if I should pull the tray out to measure the heater resistence and voltage and also to check the fan behind the evap. How do I check the fan, by measuring its resistence too? Thanks.

 

[paulhl]

Check bottom of evap to make sure all water drained. With all doors shut except that drawer push in on that toggle in post 15 and that fan should come on if the evap is below 35. Hah, I thought I posted this @ 4:30 this AM. Anyway that ice is right over the drain hole and probably under the evap and blocking the fan.

 

[georgepb]

So it's looking more and more likely the drain heater might be bad? To check the fan when the evap is below 35 I'll have to wait until the unit is turned back on and running for a while.

 

[paulhl]

Melt that ice

 

[georgepb]

Doing that now with a hair dryer

 

[georgepb]

 

[paulhl]

What is that in the hole pushing against the heater

 

[georgepb]

Nothing I can tell. I jiggled around a bit and it moved freely.

 

[paulhl]

OK, why is there hair down there? You should slide out tray,(leave it out) find drain pan full, and then check ohms on heater. Put top back on evap, insert drawer, turn back on. Let run for a few hours so evap temp is 20 or it will not go into defrost. Then remove drawer and push that toggle switch to see if fan runs. Then shut down, wait 10 sec and turn on and check for power to drain heater. If all OK I would pull out the heater and re-insert to make sure that drain is clear. When earlier ser #'s had this problem we would disconnect the evap thermistor which would force a 20 min defrost every 6 hours.

 

[georgepb]

Got it. I'll try to get as much of this done as possible this weekend. Will keep you posted. Thanks again for the help.

 

[georgepb]

I slided the tray out and the drain pan was full of water as you predicted. I unpluged the train heater and measured its resistence. It showed 100 ohms (10x10). Can it be right? Also, the plug appeared to be very loose.

 

[paulhl]

Specs say 1900......Measure the def heater to see if meter is OK, 21 ohms

 

[georgepb]

To reach def heater I have to remove the ice maker and the back panel? I'll try to caliberate the meter first..

 

[paulhl]

No, the connector should be top r/s of evap close to terminator

 

[georgepb]

Little hard to reach for me.

 

[paulhl]

Yeah, if you do remove back panel be careful with baffle on l/s, you must remove the reed switch also. Can probably just slide it up a little to access the connectors. Did tech that replaced terminator remove it.

 

[georgepb]

No, he did not. He just removed the evap cover and replaced it in <10 min.

 

[georgepb]

I caliberated my meter using a few known resistors and the drain heater is 2k ohms +/- 5%

 

[georgepb]

Hi Paul, in case you are still monitoring this thread, it's been two weeks since the unit was completely defrosted and restarted
and it worked fine until yestereday when the temperature on the refrigerator side began to inch up, from the set temp
of 37 to 40 then 42 then 46 and it was 51 last checked. The freezer part stays normal at 4. Any idea what could cause this?
I put everything back including the evap cover. Since this is a single-compressor system I wonder if there is something
wrong with the baffle control. And since it took nearly two weeks for this to happen I wonder if there is ice build-up again
somewhere that cause the baffle to stop working. I could be totally off base here. I appreciate any guidance you can provide.