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FIXED 106.64942400 Kenmore Coldspot temperature thermostat problems

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GKH

Premium Member
Joined
Mar 24, 2022
Messages
5
Location
middle tx coast
Model Number
106.64942400
Brand
Sears Kenmore
Age
More than 10 years
model # 106.64942400 , serial # er1936595, manufacture date 2004

Frig & freezer would get warn sometimes.
found out closing door hard or tapping the stat got it going again then repeat days later.
changed the stat with after market because new OEM was not available anymore that I could find.
worked Ok for a few months and then frig was freezing everything inside.
could not turn off with the stat, had to unplug the cord.

Opened up the stat and found plastic parts that the contact came in contacted with melted some.
Pics attached
Bought another stat and installed.
it froze things in frig withing a day or two ,even when stat was turned down to almost the off position.
But it did turn of the compressor
temps in frig getting down into the 20s

measured current at the plug cord and it pulled 1. 2 amps after the quick inrush and then slowly dropped to less than .9 amps.
when the compressor sometimes cycled back in to quickly to let the pressures equalize the start amps went above 6 amps and stayed there until the thermal at compressor opened up.
after that cooled down enough the compressor started up normally.
I found 2 adjustments on the stat besides the normal knob you turn to adjust.
one between the 2 electrical prongs for the contacts
and the other under the knob you turn( I adjusted this one clockwise a little at a time and have the temps in frig staying around 35-36 F and freezer around Neg 1 or 2)

Questions I have is there a way to set dead band on the stat so the compressor stays off longer before it comes back on?
maybe the other adjustment screw I see, or is that for something totally different.
Would like to give it a few more degrees seperation of turning off and then back on.


sometimes it cycles back in in less that one minute and causes the thermal overload to trip.
I am fairly sure this is what over heated and melted plastic around the contacts.
that and power blips which will bring the compressor back on as soon as power returns to the plug.

I do not see anything in the circuit but the defrost electronic timer/control board , the stat, and the thermal overload going to the compressor,
Is there something that is suppose to control the re-energizing of the compressor that I am not seeing?
I would think a delayed on energize relay set in line on the neutral side of compressor would cure this,
but I am not sure what is suppose to control this from happening.

any incite on this old frig system would be appreciated if my questions can be answered

Thanks
GKH



IMG_20220324_092216578.jpg IMG_20220324_091724696_BURST001.jpg IMG_20220324_092137023.jpg
 

Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
5,274
Location
Ontario, Canada
What is going on, I would have expected some kind of reply by now

If someone knew they would have said something.


is there a way to set dead band on the stat so the compressor stays off longer before it comes back on?
maybe the other adjustment screw I see, or is that for something totally different.

I personally don’t know what company manufactured whatever control you installed nor what calibrations it is set at nor what adjustments might be available on it. Thermostats are not ‘all the same’. All we’ve seen are pieces of one.

Normally appliance technicians just replace defective parts anyway, not recalibrate them, so it’s pretty unlikely one would even know how to do it in order to tell you.

Did you try asking whomever you purchased the replacement part from?


GKH said:
Is there something that is suppose to control the re-energizing of the compressor that I am not seeing?

No.


Dan O.
 

GKH

Premium Member
Joined
Mar 24, 2022
Messages
5
Location
middle tx coast
Well, it seems that this frig does not have something to control the quick re-energizing of the compressor from the stat or other things like someone playing with the stat or power blips.
so, I will see if I can install a time delay relay or other device to limit the compressor from coming back on within a set time, so the pressures have enough time to equalize

I realize that the new aftermarket parts we find on the web are not equal to OEM a lot of the time,
but even OEM stats have the same screw adjustments so I thought someone would have some Idea of what they were for.
that is all I was looking for

oh yea I posted the pics so you all could see the melted plastic parts and the screw that I had no idea what it did
 

Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
5,274
Location
Ontario, Canada
even OEM stats have the same screw adjustments so I thought someone would have some Idea of what they were for

There are several different manufacturers of domestic refrigerator thermostats. They are not all designed the same. Now there are thermostats being made in other countries by different companies using different designs yet again. As I said, we have no idea which thermostat design you are dealing with. Is it a GE, Cutler-Hammer, Ranco A10 or K50 design or some off-shore brand? And then you have to find someone that knows the calibration of that specific make and design of thermostat. As I said, they're not all the same.

g/l

Dan O.
 

GKH

Premium Member
Joined
Mar 24, 2022
Messages
5
Location
middle tx coast
thanks, I understand techs do not try to calibrate the stats, just put new parts in.
just thought someone would have some idea.
not many people have the same desire to know what makes things function like I have.

the after-market one looked the same inside and out with the same screws for adjustment.
just thought someone had an idea.

I have a feeling the newest stat has also bit the dust to the melting of plastic due to the current flow during locked rotor, temps in frig have dropped and turning on and off of the compressor has become erratic now. So I unplugged it

I may install a transformer 120/24V and relay that the stat sends voltage/current to so it does not see compressor current, and the relay carries the Locked rotor current when needed, or see if I can source a time delay relay to install to limit how quick the compressor kicks back in.

If I come up with an answer to my questions or fix my problem I will remember to report back on this thread
 
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GKH

Premium Member
Joined
Mar 24, 2022
Messages
5
Location
middle tx coast
Just to let others know my work around fix of my problem.
I used the stat contact to energize a 120/24 volt transformer that when energized picked up a 24 volt relay with 2 normally open contacts.(I paralleled the contacts just so they would share the load)
I had those parts laying around.
so the stat contact is no longer taking the locked rotor current of the compressor and melting the plastic around those contacts.


but there was some erratic opening and closing of the stat contacts, bouncing the relay and compressor still causing the compressor to kick out on over load too many times
So picked up a delay on energize electronic relay for $9.99 on amazon. only good for 1 amp
put it on the 120v up side of the transformer and set for 3 minuets, so the system can equalize before restarting the compressor.
it seems to be running well at this point, but I ordered another $13 stat just so I start out with a fresh one that has not seen enough current to melt the plastic and should never see that current anymore with these modifications
 

Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
5,274
Location
Ontario, Canada
Thanks for the follow up.


Dan O.
 
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