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KFIS29PBMS01 both FC and RC don't reach set temperature


max999

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3 hours ago, max999 said:

the pressures are 5PSI and 140PSI

Lowside should be 0 psi. Did you home the 3-way valve for servicing?

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Could it be that  the freezer is defrosting too often and not allowing the freezer to reach the set temp of 0F and lower? I know I did set the defrost cycle to basic defrost,  in the diagnostic , which is every 8hours. What do you think? 

also, Since the cover in the back of the fridge was off I tough air from the condenser fan is not cooling the compressor/condenser fast enough so I added a external fan and I noticed improvement overnight, the freezer was at 5F. Is it possible that the compressor is not efficient? And can’t compress the liquid gas well enough? 

again the compressor pressures equalizes very fast when off so I don’t think it’s floating restrictions,  
 

what about compressor thermal overload ? That too wouldn’t allow the freezer the set temp. how can I tell if the compressor is off due to thermal overload or off because it’s in defrost mode ? 

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I  noticed , that when the  compressor is off the temp in the freezer rises (fridge is s fine )meaning that it is in defrost mode.  I checked the inside of the freezer and I can hear water drop Sizzling on defrost heater. So I don’t think it’s compressor thermal overload.  

I think this is a new problem, and it may be the main board issuing defrost too often, what do you think? 

The equalized pressure when the compressor is of is 35PSI , what is normal equalized pressure? 

I’m  not going to give up until I understand what is wrong with this expensive fridge. 

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4 hours ago, max999 said:

Could it be that  the freezer is defrosting too often and not allowing the freezer to reach the set temp of 0F and lower? I know I did set the defrost cycle to basic defrost,  in the diagnostic , which is every 8hours. What do you think? 

Shouldn't be a problem, recovery from defrost should only be about 15 to 20ish minutes of run time.

52 minutes ago, max999 said:

I  noticed , that when the  compressor is off the temp in the freezer rises (fridge is s fine )meaning that it is in defrost mode.  I checked the inside of the freezer and I can hear water drop Sizzling on defrost heater.

Wonder if the defrost heater is on all the time. If defrost is set to every 8 hours the heater shouldn't be on when the compressor stops running. Easy test is to check the voltage and amp draw of the heater.

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The label on defrost bi-metal sitting on The freezer evap suction line read L48-30F. Which mean it closes under 18F and open above 48F.
Is it the correct bi-metal ? What should be the correct freezer bi-metal open/close temps ? 

So is it possible, as you indicated , that the heater is on all the time and main board think it’s time to defrost? 
The temp in the freezer goes from 10 to 28F when it is on defrost.That hot too fast , right?  and it means the compress has to work hard to bring it back down. So if it a defrost problem , what is the correct way to diagnose it? 

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1 minute ago, max999 said:

what is the correct way to diagnose it? 

 

22 minutes ago, Vance R said:

Easy test is to check the voltage and amp draw of the heater.

I'll quote myself, measure the heater while the compressor running.

6 minutes ago, max999 said:

The label on defrost bi-metal sitting on The freezer evap suction line read L48-30F. Which mean it closes under 18F and open above 48F.
Is it the correct bi-metal ?

yes

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I attached a current probe to measured the current the heater when compressor is on and it reads zero amps, meaning no voltage to heater.  what else can I try? 

 

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1 minute ago, max999 said:

what else can I try? 

It just means no amp draw, if the bi-metal is open  and voltage is present without a complete circuit there will be no amp draw.  According to the tech sheet check for voltage on main board P2 pin7 to P1 pin2 for 120 vac.

 

Your picture doesn't pull up.

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Ok, can see it now. Looks about 3/4 frosted which could be ok depending on how long the compressor had been running. Let's the frost, moisten your finger and touch the frost in several places. Start near the capillary tube. Let me know the results.

Another test since the evap cover is off, use a damper paper towel and touch the defrost heater to see if it is warm/ hot.

Edited by Vance R
added test 2
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so, I did probe P1-pin2(blk-wht)/P2-pin7(pk) wires when the compressor is on and read 0V , the freezer temp is 9F , pressure are 1PSI/140PSI and I sent frost pic again. 

thanks

freezer_forst2.jpg

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should there be 120V at P1-pin2/P2-pin7 all the time or only when the main board the defrost timer (8 hours) kick in? should experiment with the fridge timer defrost setting. the option for step 38 in the diagnostic are OF,Lo,Sh; I don't  know what they mean.

I did check and moment it is at OF, which mean it is OFF, last time I checked it was set to "Sh"

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5 minutes ago, max999 said:

should there be 120V at P1-pin2/P2-pin7 all the time or only when the main board the defrost timer (8 hours) kick in?

Only when the board put the refrig into the defrost mode.

  • Thanks 1
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well something very interesting , every-time I enter diag mode step 38(Forced Defrost mode)  it always shows OF , no matter what i set it to. don't no why. Step 6(bi-metal test) read 01 meaning the bi-metal is making contact. Like I said I could swear that earlier today I could hear the heater sizzling when water droplet falls on it, now I'm confused on what is going on. The freezer frost is starting to build up on the coils 

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since I have the volt meter connected to   P1-pin2/P2-pin7 , i noticed it reads 120V and there 3.7A current draw. so it is defrosting Ok . so I think the defrost works fine. correct?

 

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question, when I set the freezer set point to -5F , the actual temp range between 1F and 25F. the 25F is due to defrost mode which is normal, the temp in the freezer will right that high to melt all the frost of the coil, right? 

and when I set the freezer set point to 5F the actual temp range between 10F and 25F. so something is going on with the set point and what the freezer thermistor thinks its reading, correct,? 

BTW, i have not seen the low side going to vacuum any longer, its between 0-1PSI. so I assume it has the right amount of refrigerant. correct? 

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Question, If the system is overcharged   could it explains why the defrost issue with the freezer not reaching set point temperature? Or maybe I’m over thinking the freezer problem, and it all normal. 

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4 hours ago, max999 said:

question, when I set the freezer set point to -5F , the actual temp range between 1F and 25F. the 25F is due to defrost mode which is normal, the temp in the freezer will right that high to melt all the frost of the coil, right? 

and when I set the freezer set point to 5F the actual temp range between 10F and 25F. so something is going on with the set point and what the freezer thermistor thinks its reading, correct,? 

BTW, i have not seen the low side going to vacuum any longer, its between 0-1PSI. so I assume it has the right amount of refrigerant. correct? 

Sounds like it’s working. You may have a sensor out of spect or you temp measurements are a tad off. Depends on where and out your taking measurements.

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27 minutes ago, David C said:

Sounds like it’s working. You may have a sensor out of spect or you temp measurements are a tad off. Depends on where and out your taking measurements.

 

That is true , it possible it’s where I’m taking the reading with remote temp sensor. I will reposition the sensor. 
Btw , I did measure freezer thermistor and the resistance was right on the money. 

If the system was overcharge , it will not cause freezer defrost issue , right ? 
if so I have been overthinking the temperatures too much, because I saw defrost causing temp to rise by 25F and it is Normal. 

I hope it stay like this in the next few days. Thanks for all your knowledge. 

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On 10/9/2021 at 1:04 PM, max999 said:

so I think the defrost works fine. correct?

yes

 

4 hours ago, max999 said:

If the system is overcharged   could it explains why the defrost issue with the freezer not reaching set point temperature?

Not so much a defrost issue, the evaporator should run at -15 deg f to get a 0 deg f freezer. We are coming back to operating pressures. The lowside should be at 0 psi to get evap to -15 deg f.

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With respect to the low side pressure , I understand that when a system is charged correctly, pressure should be at 0psi , but when the compressor changes speeds I noticed that low side pressure fluctuate and that is normal right? It can’t be at zero at all time . And when the compressor is off the pressure equalizes not at zero.
In a functioning fridge what should be the pressures at all time throughout the fridge cycle? .  

so, maybe my system is overcharged a little , since it never sits at zero , it’s at  1-2 psi 

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15 minutes ago, max999 said:

but when the compressor changes speeds I noticed that low side pressure fluctuate and that is normal right? It can’t be at zero at all time

yes, it should be around 0 psi when running full speed.

18 minutes ago, max999 said:

In a functioning fridge what should be the pressures at all time throughout the fridge cycle? .  

The easy answer is it will change depending on heat load and compressor run speed. 

 

19 minutes ago, max999 said:

so, maybe my system is overcharged a little , since it never sits at zero , it’s at  1-2 psi 

 Did you charge by weight or pressures?

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