Brand: Kitchen Aid Model Number: KRMF706ESS01 Main Symptom: Not getting cold What happens & when: When running
Error Code (if any):
Parts or tests already tried: Tested compressor, getting 13 ohms on the three pins. Checked the condenser and condenser fans, appear to be running properly, with no frost/ice on coils. Compressor fan working properly. Compressor comes on and runs as it should, but no cooling. The coolant lines are not hot or cold coming and going to the compressor. Decided to replace the inverter control board AP6048051 (W11087200) after doing some research and determining that could be a possibility. After 24 hours, refrigerator still not cooling. Checked the condenser and condenser fan again, seems to be working as it should. Went ahead and called a service tech. He did some tests on the system and determined there seemed to be a clog in the coolant lines. He evacuated the entire system, using a nitrogen and replaced the dryer filter. Recharged with 134a as per specs on the serial number/model number label. 24 hours later, still not cooling at all. Before these issues, there were a series of brief power failures from the power company—maybe 5 seconds or so. Refrigerator came back on, but was not working. I turned off the power for 10 minutes and when turned back on, refrigerator was working. A couple of days later is when it stopped working. LED lights inside are flickering when you open the door, not sure if that is related to anything. I know they are wired in series, and I did have a couple of the lights out previously. I am not opposed in changing out the power control board, but refrigerator turns on and seems to run ok. No clicking or humming, and he compressor does not get hot while running. Just no cooling. Any recommendations are appreciated. Thank you.
Based on everything you’ve already done, you’ve ruled out most of the common electrical failures. The sealed system work performed by the technician also makes this a more unusual diagnosis.
Here’s how I’d look at it.
What your testing tells us
Compressor windings measure about 13 Ω across the three terminals, which is reasonable.
Compressor is running.
Condenser fan is running.
Evaporator fan(s) are running.
Inverter board (W11087200) has already been replaced.
System has been evacuated, nitrogen flushed, a new filter drier installed, and recharged with the factory amount of R-134a.
After all of that…
The discharge line leaving the compressor should become noticeably warm within a few minutes, and the suction line should begin getting cool.
The fact that both lines remain close to room temperature is the biggest clue.
The two most likely possibilities
1. The compressor is running, but not actually pumping refrigerant (most likely)
Variable-speed compressors can fail mechanically while still running quietly.
Common failures include:
Broken internal valves
Worn piston
Internal bypass
When this happens:
Compressor sounds normal.
Current draw may even look normal.
Windings ohm correctly.
No heat develops on the discharge line.
No cooling occurs.
This is actually more common than many people realize.
2. The inverter isn’t commanding the compressor correctly
Even though the inverter has been replaced, it only does what the main control board tells it.
If the control board isn’t sending the proper PWM communication signal, the compressor may only idle instead of ramping up.
The compressor can appear to be running but never develop enough compression.
I’d verify compressor current draw
This is the next test I’d perform.
Use a clamp meter around one compressor lead.
A healthy compressor on this model typically draws somewhere around:
0.6–1.3 amps depending on operating speed and load.
If you’re only seeing something like:
0.1–0.3 amps
the compressor usually isn’t producing compression.
Check the compressor speed command
The service manual has you verify:
120 VAC supplied to the inverter.
Proper communication signal from the main board to the inverter.
If the inverter isn’t receiving a valid command, it defaults to a very low speed.
Since you’ve already replaced the inverter, I’d verify the main control board is actually commanding full compressor operation.
About the flickering LEDs
This is actually a separate issue.
On the KRMF706ESS01 the LED modules are wired in series.
A failing LED module commonly causes:
Flickering lights
Dim lights
Multiple lights out
It usually does not cause a no-cooling condition.
However…
The main control board powers both the LEDs and communicates with the inverter, so a damaged board from repeated power interruptions could potentially explain both symptoms.
Considering the power outages
This part of your story caught my attention.
The refrigerator temporarily worked after you unplugged it following several brief power outages.
Power surges can damage:
Main control board
Inverter
Compressor electronics
You’ve already eliminated the inverter.
The remaining electronics are primarily the main control board.
My recommendation
Before replacing another expensive part, I’d perform these final checks:
Measure compressor current draw with a clamp meter while it is running.
Feel the discharge line after 10–15 minutes of operation. It should be hot enough that you don’t want to hold it for long.
Verify the inverter is receiving proper voltage and communication from the main control board.
If the compressor is drawing very little current and neither refrigerant line changes temperature after the sealed system has been properly evacuated, repaired, and recharged, I would strongly suspect a mechanically failed compressor, even though it runs quietly.
If compressor current is normal but the inverter is not receiving the proper control signal, then the main control board (WPW10675033) becomes the next likely suspect.
One question for the technician
Did they connect refrigeration gauges after the repair, and if so, what were the high-side and low-side pressures with the compressor running?
Those pressure readings would tell us very quickly whether the compressor is actually pumping refrigerant or simply spinning without creating compression.
Ok, so the tech that worked on it is suggesting that it could be a condenser clogged with oil. Said to start with evaporator in the refrigerant compartment for $650 and if that doesn’t work to do the evaporator in the freezer compartment for $545. It seems much more likely to me that it is a control board not sending a proper signal to the inverter, thus not letting the compressor ramp up to build pressure as you suggested. The oil clog, to me, does not seem like the issue, and I am wondering why he would not suggest testing the boards first?
I already placed in order for overnight delivery on the main control board WPW10675033. I will test the compressor as suggested above tonight. I am not investing $1200 on condensers, especially if they cannot guarantee that will fix the issue.
Compressor windings measure about 13 Ω across the three terminals, which is reasonable.