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FIXED PFCS1RKZASS GE Profile not regulating temp correctly. Display temp incorrect

TIMANDREWS

Premium Member
Joined
Mar 16, 2018
Messages
10
Location
canada
Model Number
PFCS1RKZASS
Brand
GE
Age
6-10 years
My GE profile fridge is not regulating the temperature correctly. Originally the unit was not cooling due to a bad inverter board. When I replaced this I noticed the 'actual temp' digital display did not change as the unit cooled (both the freezer and fridge). When I unplug the unit and plug it back in the digital display with change to match the thermometer at that moment but does not change as the fridge continues to cool.

I put two thermometers in it and let it run for a few hours when I returned:

1) the fridge had finished cooling and shut off. Both the thermometer and display matched. Perhaps because I unplugged it and plug it back in before I left.

2) the freezer was still cooling. The thermometer read -15 and the display read 0

I unplugged the unit and open the doors and let it warm until it was about 10deg above the set temps of 0 and 37. I closed the doors and plugged it back in.

3) The compressor and fan took a REALLY long time to turn back on. Must have been at least 15min. Long enough for me to worry I fried something

4) once again, the digital display did not reflect the actual inside temps. When I unplug it and plug it back in they change to match the thermometers but don't change as the unit cools.

Any suggestions to help solve this issue? Im gonna check the thermistors shortly. right now I have a sick kid and wife.

Many Thanks

Tim
 

TIMANDREWS

Premium Member
Joined
Mar 16, 2018
Messages
10
Location
canada
Thanks for the reply Rick.

Before I drop another 200 bucks into it, I'd like to check the cheaper possibilities first. I found a thread on here with a similar issue and when they replaced a thermistor the problem was solved. I opened it up today. I'm having a hard time finding the CC thermistor and the FF evap thermistor... could someone give me some directions to them? Im about to check the parts diagrams to see if I can hunt them down that way.

Thanks
 

rickgburton

Appliance Tech - Moderator
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Messages
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Location
Murray, Utah 84107, United States
The thermistors can be checked at the board or in diagnostic mode. You have four thermistors, freezer, fresh food, ambient and evaporator. the freezer and fresh food thermistors are behind the small grill and look like this:
Snapshot_5.jpg

The ambient thermistor is located under the freezer section:
Snapshot_4.jpg

The evaporator thermistor is located on the inlet side of the evaporator:
Snapshot_3.jpg

Some of the connector labeling and wire labeling may be different than on your board. However the function and diagnosis of the connectors and wiring is the identical for all models. The correct way to test a GE thermistor is to place it in a small glass of crushed ice and just enough water to cover it. Wait several minutes. The temperature will be close to 33*F. At 33*F the thermistor should have 16.3K ohms of resistance (16,3000 ohms).
GEMB-02.jpg

To check the thermistors is diagnosis mode: The temperature display must be in an active mode before entering the self-diagnosis test. If the display is blank, press any temperature button once, then release it. The display will show actual temperatures.
Enter the diagnostic mode by pressing both the freezer temperature (COLDER and WARMER) pads and the refrigerator temperature (COLDER and WARMER) pads simultaneously. All 4 pads must be held for approximately 3 seconds. Blinking "00"s in both the freezer and refrigerator sections of the display indicate the refrigerator has entered the test mode. Remove your fingers within 5 seconds and press any pad to lock-in the test mode. The blinking "00"s will change over to solid (non-blinking) "0"s when the test mode is locked in. Failure to lock-in the test mode within 30 seconds will time out the test and return the refrigerator to the normal cooling mode.

Thermistor self test: Freezer Display-0 and Refrigerator Display-7
This test checks each thermistor in order and displays, "P" Pass, "0" Open or "S" Shorted. The order is
1- Fresh Food
2- Ambient
3- Freezer
4- Evaporator
5- No thermistor installed in this location. Display may show "0" open.

WR55X10025 Temperature Sensor
ge-temperature-sensor-wr55x10025-ap3185407_01_m.jpg
 

TIMANDREWS

Premium Member
Joined
Mar 16, 2018
Messages
10
Location
canada
Hello Rick,

Thanks again for your response. I read over several similar threads last night and although it wont help me solve the problem (unless I just replace everything) this thread help put things in perspective, specifically the alligator analogy; so thanks for thanks for that as well :)

https://www.applianceblog.com/mainforums/threads/46515-ZICS360NMRH-GE-Monogram-36-bottom-freezer-refrigerator-Freezer-too-cold-10-Fridge-at-44-F

Yesterday I tested all 4 thermistors using the ice water method. My results were not the Ideal 16.3 @ 32 F but I feel they are good enough to eliminate the thermistors as the problem. What do you think? Ive included the ice water temp as measured using a digital meat thermometer. The part is cheap, and easy to replace so I don't mind changing out the two with low readings. The pins are labeled according to the self diagnostic sequence but the only one I am certain of is pin2.

pin 1 (FF): 14.9ohms (32.5 deg)
pin 2 (Amb): 15.7ohms (32.9 deg)
pin 3 (FZ): 15.8ohms (32.8 deg)
pin 4 (EVP): 14.9ohms (33.9 deg)

In the thread link above you said a fridge takes about 24hours to settle in? I don't know how long the unit has been sitting before I acquired it but after I replaced the inverter board I only really let it run for 6 to 8 hours (empty) before I noticed the issue with the display temps and the actual temp, as well as the freezer still running. Then I unplugged it.

Would it hurt anything to just let it run for 24hrs or more and see what happens? If not, I think this will be my next step. After 24 hrs, Ill run through all of the self diagnostics I can and see what happens after it runs for a while. Ill keep an eye on the damper and check the coils. what ever I can check I will. Who knows.

A couple other questions:

1)The Mother board image you included above has a CC thermistor labeled on the J5 connector at pin 6. on my J5 connection there is a wire in Pin 6 but when I pulled the damper assembly out I didn't see a thermistor and the wire is much heavier gauge then those in J1 so I guess I can assume no CC thermistor here in my unit?

2)Could the damper have anything to do with the problem of the freezer getting so cold or continuously running? Could the damper not be closing and causing the fan in the freezer to keep running? at -20 I know the fan was running but im not sure if the compressor was running as well. Ill check this tomorrow. How does the process work – fridge gets to set temp, damper closes, freezer gets to set temp and stops cooling? Does the evap fan in the freezer always run?

3)Lastly, Today After I plugged it back in, I noticed that the area where the ice maker on the door meets the side wall of the fridge compartment gets very warm. There are two vents on the ice maker that seat up with two vents on the side wall when the door is closed. on the side wall, I can feel cold air coming from the lower vent but not much of anything coming from the upper vent. The wall above the lower vent was the warmest. The inside of the ice compartment was cold. Is this normal operation? I assume yes. It would make sense that there would be heat generated from the ice maker. The lower vent brings cold air in and the upper lets the warm are out?

I only hung around for about 10min after I plugged it in. I will check on it tomorrow.

Again, Many many thanks and much appreciation!

Tim
 

TIMANDREWS

Premium Member
Joined
Mar 16, 2018
Messages
10
Location
canada
Hey Rick

Not need to respond to Q1 and Q2 above but Im curious about Q3.

I haven't had a chance to get back to it yet. Ill post when I do.

Thanks
 

rickgburton

Appliance Tech - Moderator
Staff member
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Messages
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Location
Murray, Utah 84107, United States
Hi Tim,

There's no thermistor for custom cool in your machine. The evaporator fan motor is a variable speed DC fan motor. The ice room uses a dedicated 3 speed DC fan motor and duct. The fan speed and on-time are calculated using a multitude of algorithms. The ice room fan uses either 100% duty cycle or 50% duty cycle. When on 50% duty cycle the fan cycles on-off every 20 minutes. The fan is off when the compressor is off and during the defrost cycle. If the damper is open for longer than 2 hours the fans will turn on low speed until the damper closes.
ice room fan.jpgice door vents.jpg
 

TIMANDREWS

Premium Member
Joined
Mar 16, 2018
Messages
10
Location
canada
Thanks,

What are your thoughts on the hot spot on the wall just above the lower vent in the area seen is image tow from your last post? is that normal? I don't know if is always there or just during the initial cool.

Ive also read conflicting info regarding the compressor temp. Most recently I've read that these inverter comps should run warm to room temp. During the initial start up/cooling, i notice it got pretty warm... I'd almost call it hot but i could hold my hand on it with out any problems. The coils were clear and i could feel cool air coming off the fan. I know that with the back off less of the fan air is retained so its harder for the comp to cool but Is it normal for it to run a little hotter then normal when its working harder to cool a warm the fridge?

I am now almost certain that the inverter failure was due to air flow problems. it was discolored yellow where it touched the compressor when i removed it. There was a ton of dust on up of the unit, and coils showed signs that they were once cemented with dust. Im will check the windings again just to see but im pretty sure they were all 7+ohms when I first checked it.

Thanks again! have a great day!
 

TIMANDREWS

Premium Member
Joined
Mar 16, 2018
Messages
10
Location
canada
Hi Rick,

I just checked on the fridge. Im am far from an expect but based on several other threads, Im gonna say that the fridge is acting normally. The compressor was luke warm when I arrived this am, all temps checked with-in reason. I opened and closed the doors periodically to mimic normal use and the compressor turned on and off as it should.

Still, Im courious about a few things for future reference and to put my mind at ease:

1) the hot side wall at the ice maker vents as discussed in my last post - is this normal?
2) There seems to high pitched frequency kind of noise and a bit of heat generated by the mother board - I assume, because the board is like a computer, the heat and noise are both normal?

Im gonna let it run for a few days and see how it goes. I have a digital thermometer in both the FF and FZ that will log daily min and max temp. If there are no crazy temperature swings, Ill bring it home.

Thanks so much! This forum is fantastic.

Tim
 

TIMANDREWS

Premium Member
Joined
Mar 16, 2018
Messages
10
Location
canada
Hello again,

I did some more reading and now I understand the icebox vents and how the air flows, but I still don't fully understand why it'd be warm above the lower vent. I have the toggle switch off in the ice box would this turn the ice box fan off? that'd be why there is no air coming through the upper vent.

Tim
 

rickgburton

Appliance Tech - Moderator
Staff member
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Messages
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Location
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Air duct and supply duct heaters are connected in parallel and located inside the left-side fresh food door. Air Duct and Supply Duct heaters will come on with abnormally high door-open time and high humidity. (Abnormal = approximately 70 fresh food door openings for 12 seconds or more in a 16-hour period.) Applied voltage to this circuit can be tested at the main control board J8 to J7-9. Your machine has an inverter compressor so the J8 COMP connector is not used for the compressor

The duct port heater is located inside the left-side fresh food door around the ice compartment portholes. The duct port heater cycles on temperatures and ice compartment conditions. (Mid-settings = heater on time approximately 30%) Applied voltage to this circuit can be tested at the main control board J7-5 to J7-9.
 

rickgburton

Appliance Tech - Moderator
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Messages
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TIMANDREWS

Premium Member
Joined
Mar 16, 2018
Messages
10
Location
canada
Rick,

Thank you for the info on the ice box system. Aside from the warm area around the ice box vents, Id say im okay, almost happy with how things are running.

while I was there today - the temps in the freezer dropped to -21F and then went up to 5F before returning to normal - I presume this was the prechill and defrost cycle.

With respect to the ice box:

I checked the inside wall and it was warm as I expected. I turned the ice maker on. then measured as follows:

Air duct and supply duct heaters: @ J8 and J7-9 = 0volts. could you confirm that J8 is the correct pin. There was no wire going into the block for the J8 connector and J7-9 is neutral.

The duct port heater: @ J7-9 and J7-5 = 0volts

- I presume that 0volts means the heaters are off and you'd have to get them at the correct time to measure a voltage here correct?

Ice box fan: 7 volts (evap fan on) and 0 volts (evap fan off). I could feel a very light breeze coming from the upper vent but not much so the fan either running VERY slow or not running at all.

- I guess the heat I am feeling is what is left over when after one of the heaters has recently or is currently turned? due to lack of circulation...

- Does the ice box fan turn on and off with the evap fan, or is it controlled something else? Is the voltage variable depending on the ice box conditions? There is no water to it and there for no ice being made, and therefore little requirement for added cooling so little to no reason for the fan to run. Im just wondering if there is something that could be limiting the voltage, before I replace the main board


- It was pretty tough getting in some of those holes with my probes, can I remove the terminal strip and just measure the pins on the main board?

- Can you put dielectric grease into the connections? I'm just wondering if some of the connections are weak.

Thanks again. I must say, This must be a very interesting career, ever changing and always lots to learn and problem solving. You guys have my respect.
 

TIMANDREWS

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Joined
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Messages
10
Location
canada
Okay,

Im gonna knock on wood and say this thread can be marked as fixed! (YAY!) This question still lingers on my mind a little:

" Does the ice box fan turn on and off with the evap fan, or is it controlled something else? Is the voltage variable depending on the ice box conditions? There is no water to it and there for no ice being made, and therefore little requirement for added cooling so little to no reason for the fan to run. Im just wondering if there is something that could be limiting the voltage, before I replace the main board"

In conclusion, for anyone reading this post:

1) my biggest problem was that, because I acquired this fridge broken, I didn't know how it should normally work.

2) I don't know about the heat around the ice vents, but the ice box is cold as can be, so it cant be hurting anything and its possibly normal. it does not seem to be affecting the fridge temps.

3) The digital temp display does not give instantaneous readings. Its not gonna pick up that 5 degree change while you had the fridge door open. If you are comparing (disp vs actual) temps using a digital thermometer allow for +/-5 degree F

4) the prechill and defrost cycle can produce a significant temp swing. Mine seems to go to -20 then to +6 over about an hour before it returns to normal. There is info with-in this forum to support that.

Thanks again Rick. This has been a great learning experience.
 

rickgburton

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I somehow missed your last post. Sorry about that.

rickgburton said:
Air duct and supply duct heaters are connected in parallel and located inside the left-side fresh food door. Air Duct and Supply Duct heaters will come on with abnormally high door-open time and high humidity. (Abnormal = approximately 70 fresh food door openings for 12 seconds or more in a 16-hour period.) Applied voltage to this circuit can be tested at the main control board J8 to J7-9. Your machine has an inverter compressor so the J8 COMP connector is not used for the compressor

The duct port heater is located inside the left-side fresh food door around the ice compartment portholes. The duct port heater cycles on temperatures and ice compartment conditions. (Mid-settings = heater on time approximately 30%) Applied voltage to this circuit can be tested at the main control board J7-5 to J7-9.

This is a typical temperature chart for GE pre-chill and defrost.
Prechill.jpeg
 

TIMANDREWS

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Messages
10
Location
canada
With out a doubt, the heat im feeling is coming from the duct port heater. Ill probably call GE and Inquire but Im thinking its normal. It may turn on when the door opens. If I find it to be a problem, Ill start a new post.

Thanks again.
 

rickgburton

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rickgburton said:
The duct port heater cycles on temperatures and ice compartment conditions.
My guess is that's normal. Everytime you feel the heat the compressor is probably running.
 
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