Refrigerator compressor runs only few cycles when first powered (Kenmore 795.74113.710)

[psufcak]

Fridge-freezer unit, SN 804KR00272.  First issue was freezer melt-down. Didn't have time to deal with it, my appliance tech replaced the linear compressor.  The compressor cooled fridge to 37F, shut off, started again at about 43F and cooled to 36.7 and never restarted again. The compressor only ran two cycles over a weekend.  When we came back, I turned off power for a bit, plugged it in and compressor started. Again ran just 3 cycles and no more. Notably, the compressor makes more noise than it used to (before replacement).

Our appliance tech came back and replaced the motherboard, after some other tests. I wasn't here, unfortunately, so don't know any details what he tested or otherwise changed. 

Since I have a GoVee WiFi thermostat and hygrometer in the fridge section, I get very detailed readings from that (great little thing btw).  So after the new motherboard initial power-up, I see temperature drop to about 37F, the compressor subsequently ran 8 normal cycles maintaining the fridge within 35.6F and 41F range (see pic).  Great - except after that it stopped and temperature steadily increased to room temperature and stayed there. Nobody in the house, doors closed and no other interference.  When I got back, I turned power off/on, fridge compressor kicked in, quickly cooled the fridge in about 1.5 hrs from 78F to 45F (fridge is set to 37F), now the temp has climbed to 52F and compressor has not started again.

Suggestions for troubleshooting steps? Process of elimination?

[vunger1]

need to do an amp draw with compressor running.

need to verify thermistor operation

[psufcak]

Thanks @vunger1  I am told that the thermistor is OK.  Frankly, don't fully trust that - will have to run some tests when I get back to the property. 

Where can I find what the normal amp reading should be when the compressor is running, steady state?

[Vance R]

Check to see if the inverter led is blinking. Then put it into the test mode for compressor full speed and check high and low side pressures.

[vunger1]

On 9/19/2022 at 10:38 PM, psufcak said:

Thanks @vunger1  I am told that the thermistor is OK.  Frankly, don't fully trust that - will have to run some tests when I get back to the property. 

Where can I find what the normal amp reading should be when the compressor is running, steady state?

As a general rule of thumb I would think between 1-3amps. Anything outside of this range would be indicative of sealed system issue. The amp draw in this way is more of a quick check to eliminate anything that is obvious, and it’s easy to put a watt meter in the wall or an amp clamp around compressor wire.  

As noted, Lg provides diagnostics in the form of blinking light on the main board.( if it’s blinking , how many times?)

 

[psufcak]

There is no LED blinking on the main board.  The LG board part no. is EBR83806911 - in fact I can't even find an LED on it.  No blinking means no error codes, as I understand.

Both the freezer thermistor and the fridge thermistor seem to be working find, I check the resistance at room temp and at ice-water temp and both seem fine.

Every time I power off the fridge and then power back on, the compressor will run until the fridge reaches about 35F (as set), then in stops, when temperature rises about 2-3F then it kicks in again, and this cycles repeats anywhere from 1 to 8 times. Eventually the compressor never restarts as the inside temperature rises and the the fridge equalizes with room temperature, the compressor never starts again (unless I toggle the power off/on again, in which case the cycle repeats more or less the same). Interestingly, the fan at the back by the cooling coil runs even when the compressor does not - I thought when the fan is ON the compressor should have voltage and run, correct? 

Since the thermistors work, and the compressor obviously is capable of running, and not just for a few minutes, I suspect the main board is flaky - otherwise what else ?   Perhaps even though we replaced the original main control board, the replacement board may actually be faulty too, so I ordered another one. Should be here in a couple of days.

 

[psufcak]

@Vance R - forgot to mention, when the technician was here and replaced the compressor, he checked the high/low pressure and said all looked fine.  Yes, that was back nearly a month ago when the tech first replaced the compressor and then a week or so later replaced the main board. Something just doesn't add up... 

[Vance R]

30 minutes ago, psufcak said:

No blinking means no error codes, as I understand.

yes that is correct

Looked up the compressor at sears and encompass the original is a tca36491302 and subs to a tca36491304. Is this the one that was installed? 

The board is a ebr83806911

picture of led

 

Kinda rare a 3 wire linear

 

manual is here:

 

Edited September 28, 2022 by Vance R
added manual info

[psufcak]

So this saga continues - with a big gap as I was out of the country.  To sum up the status:

- on first power-up the fridge runs, cools down as it should, goes through a few duty cycles to maintain temp as set, then decides to stop and never kicks in again. Until the next power off / power on, then same repeats

- compressor replaced - seems to work fine, correct part no., pressure tests good; 

- main board replaced - first replacement was suspect (box was opened, unsure if the part was really new), so another brand new board was ordered and eventually put in - with no impact on function what so ever.  No LED on the main board, so no indication of any error codes. 

- freezer thermistor and the fridge thermistor tested ok

- latest guess was to check the defrost heaters, as the defrost should activate every few hours (maybe 8 hours ?);  the tech came back to test the heaters and claims that both are ok (actually said "both elements are not grounded") and now thinks maybe it's a wiring issue (?? makes no sense to me how a wiring issue could be an intermittent or transient problem). 

This is now turning into a personal challenge !

 

[vunger1]

So it holds temp and then after some time it quits holding temp due to a failure of the compressor to run, at that point?

[psufcak]

Yes. Attached is an example - fridge was OFF and at room temp, turn it ON and it drops to set temperature and holds as it should, for a few hours, pretty steady. But sooner or later (max a few hours) the compressor does not kick in again and temp climbs to room temp.  The only way to get it to cool is to flip the breaker or unplug, wait a moment and turn it back on.

 

[psufcak]

28 minutes ago, psufcak said:

Yes. Attached is an example - fridge was OFF and at room temp, turn it ON and it drops to set temperature and holds as it should, for a few hours, pretty steady. But sooner or later (max a few hours) the compressor does not kick in again and temp climbs to room temp.  The only way to get it to cool is to flip the breaker or unplug, wait a moment and turn it back on.

 

Here is a theory:  There is a compressor overload protector (part EBG60663249) which is supposed to shut off the compressor to protect it from damage if the compressor motor draws too much current. I am wondering what could cause a delayed overload situation (ie at first everything works and there is no overload, but after a couple of hours something "builds up" to cause an overload).  Coils freezing up, if so why?  After everything warms up, the overload situation goes away, and after a power reset the compressor starts up as if nothing happened, only to (eventually) run into the same overload situation.  

Is this a plausible explanation? If so how best to prove/disprove this thesis ?

[psufcak]

I checked and the compressor overload protector maintains continuity throughout, even when the compressor stops, so that's not what prevents the compressor from running.

But I noticed that the bottom line from the compressor to the condenser coil gets really hot - is that normal?

Apparently the LG FLD090LANA compressor that's installed now is a "thermally protected system" - is there a way to test this thermal protection?

As I was typing this, the compressor stopped again but now there is a tiny RED LED flashing on the main board - 6 rapid flashes, pause, repeat.  The manual say this is Current Overload condition - either due to compressor too hot, restriction in the line, or a short in compressor). Since the compressor is new, I am betting on the restriction, and since the restriction is not permanent, I am betting on freezing of the evaporator coil(s). 

Therefore I think next step is to check the defrost heater function.  Does my logic make sense?

How do I measure the heater circuit resistance from the main control board ?

[psufcak]

So what can cause the current overload protection to kick in?

I tested the both defrost heater circuits from the main board, measured 46 ohms and 88 ohms respectively, and neither evaporator coil shows signs of freezing. 

How do I test for an intermittent line restriction? 

I don't think the dryer filter was replaced when the new compressor was put in - is that a problem?  What does the standard comp replacement procedure have to say about that? 

[Vance R]

8 hours ago, psufcak said:

I don't think the dryer filter was replaced when the new compressor was put in - is that a problem? 

Yup a huge problem, especially since linears can generate a lot of garbage when dying. 

 

8 hours ago, psufcak said:

What does the standard comp replacement procedure have to say about that? 

Replace any time you open up the system.

[Budget Appliance Repair]

And the overload protection for the compressor is the external overload protector - nothing special inside the compressor.

[Clyde]

Hi Psufcak- I have your same problem. I have a Kenmore Elite French 4 Door Fridgerator/Freezer, model #:  795.72483.411. This uses a LG Linear Compressor. First I noticed the ice maker was not working back this summer so measured the freezer and discovered was only getting down to 20F and if your are not below 15F the auto ice maker will not run. I also noticed  the fridge temp was only running 55F. Took apart and had broken fan in fridge so replace but temp still only getting to 45F. Also had problems with the water dispenser not running all the time. Took me a while but discovered had a broken intermittent 120V wire in the door fridge (opening and closing the door would make it work sometimes). I have fixed this with a plastic wall anchor spacer between the top wire hole in the door (will need a new door but trying to fix the cooling issue first to see if I want to spend $350 for a door) and now have 120V power to the water/ice maker in the door. Anyway, the 120V wire broken in the door fridge is not related to the fridge/freezer not cooling properly. 

I did not have a red blinking light which is the over current draw on the compressor you are having. So we added more R134a refrigerant last month with Leak Saver as I suspected we were low on R134a since both the fridge and freezer while working was not cooling enough (fridge 45F and freezer 20F and I had fridge set to 33F and freezer to -6F). Also the evaporator coils were only getting cold half way (which means you are probably low on R134a).  After adding R134A in late October the fridge dropped to 33F and freezer down to 10F. But then this is very strange, the couple of weeks the freezer has been slowing climbing and on this past Friday the freezer was 45F but the fridge was still 33F. My repair guy that did the R134A fill said it is a bad compressor but I do not think it is as the fridge would not be running normal. This tells me there is most likely a restriction. Also after adding the R134a last month the compressor after running for a while like yours would make a higher and higher pitched compression noise (like a vacuum sealer) and then the compressor would shut off and restart in about 6 mins or so. I now get the blinking red light 6 times which is overcurrent load on the compressor. This makes me think we added too much R134a so on Friday we took out some of the R134a. If you do this make sure you put in test mode 1 and to open the 3 way refrigerant valve and then unplug the unit. This will leave the valve open. Obviously it was a guessing game on how much to extract but when we turned back on the next day the freezer was at 0F and fridge at 33F. I am a bit puzzled but I think the problem could be like yours in that the capillary tubes (coded blue) going to the freezer are freezing up and that is a restriction causing the high side to have too much pressure and then working the compressor too hard which leads to the current overload protector being kicked on to short cycle the compressor operation. I am going to suggest you extract some R134a to see if this fixes your issue. My service tech used a bullet piercing valve for this.

Any other ideas? I am pretty certain this is a restriction causing this. Again simply removing some R134a from the system my freezer works again but not too the -6F setting but is getting down to 0-9F range. I am still debugging so please let me know if anyone has any other suggestions. Once in a while my compressor will still short cycle from the current overload (after the vacuum) but noticed it happens on colder days but does not do this on warmer days.

 

Thanks- Clyde