GE Side by Side - Frost Pattern

[SteveM]

Is there always a sealed system problem if the coils are only 2/3 frosted and completley clear on the top 1/3?

I guess another way of asking is: 

If a GE side by side refrigerator controlled by a mother board has a variable speed compressor, does the speed of the compressor affect the frosting on the coils? Is it possible that a compressor is acting correctly if the coils do NOT have a complete frost pattern, or can the speed of the compressor dictate that only a portion of the coil is frosted?  

[Samurai Appliance Repair Man]

[user=11026]SteveM[/user] wrote:

Is there always a sealed system problem if the coils are only 2/3 frosted and completley clear on the top 1/3?

No, this is not hard and fast. Frost pattern depends on lots of things: ambient temp, air flow, humidity, compressor capacity and it's match to the evaporator...

In general, in a capillary tube system, you should see about 2/3 of the evap frosted. But since a cap tube can't compensate for variables in ambient and operating conditions, the frost pattern will vary.

Turns out that compartment temp is a very good indicator of sealed system health. If you can achieve 0F in the freezer without maxing out the controls, then the sealed system is fine.

[SteveM]

Then what would keep telling the board to keep the damper door shut?

As I posted in another post, I think that the evap sensor is sensing no cooling on the upper third of the coils(even though temps correct in the freezer - based on the bread test) and the board is interpeting this to keep the door shut. Diagnostics tell me the evap sensor and damper doors are OK and OHM tests on the door and board are in range.

Thus we arrive at me first real theory? Plausible - or - off base?

[Samurai Appliance Repair Man]

[user=11026]SteveM[/user] wrote:

Then what would keep telling the board to keep the damper door shut?

This is a control problem, not a sealed system problem. Thermistor, damper door assembly, motherboard... all are suspects here until they can be proven good.

[SteveM]

It appears to me that the damper door, or whatever is controlling it, is malfunctioning. I base this on I manually opened the door and visually saw and heard the door closing while the evap fan was running and the the food door door/light switch was depressed.

I have run the following tests:

a. Checked resistance at the damper and had approximately 420 ohms between the red-yellow and white-blue wires. Which should indicate that the damper motor is OK.

b. Approximately 6VDC between the J3-1, J3-2, J3-3, and J3-4 pins on the control board. Which should indicate the electrical signals to the board are OK.

c. The following diagnostic tests were run:

  1. 0-2 (Temp Control to Main Board): PASSED

  2. 0-3 (Communication btwn Dispenser Control and Temp Control): FAILED

  3. 0-4 (Communication btwn Dispenser Control and Main Board): FAILED

  4. 0-5 (encoder Test): OK

  5. 0-7 Thermistor Tests:

Diagnostics indicated that the freezer (bottom left, below the evap coil) thermistor failed.

  6. 1-0 Damper Test: OK

I did not run the tests for the 100%run time, prechill, or defrost. I did run 1-5 (Main Control Reset) to reset the system before exiting diagnostics.

d. I also removed the light bulb in the food section for 1 day to see if the temp would return to normal - It did not.

Based on the above I replaced the freezer thermistor (twice), and although it tested OK, I replaced the damper door (door/motor/thermistor) because I think the diagnostic test only tests the mechanical function of the door, not the actual interaction between the damper and the board. Please let me know if my assumption is wrong.

I have also replaced the main board(2nd time if include previous technician) thinking replacement board was bad. Results are still the same.