Author Topic: L45-15 likely bimetal for GE SxS?  (Read 1407 times)

Offline archibald tuttle

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L45-15 likely bimetal for GE SxS?
« on: July 15, 2013, 03:07:51 PM »
just jumping out of the legion thread on GE sxs evap fan and defrost cycle issues to ask if a 45-15 sounds like manufacturers suggested range.

This is a full size, full depth GE SxS with evaporator as typical vertically oriented at back lower 2/3 of freezer. 

The bimetal is clipped to the evap tubing at the top of its chimney, i.e. the whole distance of the evaporator away from the heater which is at the bottom.

I don't have serial number because this fridge has had the tag removed.  It was some kind of comebacker or warrantied unit or something that a second hand shop had a hold of, but its been in service at this location for maybe 5 years.

I feel like the 45 could be about right but the 15 reset seems low. it ought to make it clipped to the tubing but I feel like that could get on the bubble of resetting, esp. because the clip doesn't even seem to fit right and it likes to pop off the tubing.  I was thinking something more like 50/30 might be a better bet.  I haven't been able to get the thing to close even though it was brand new last year.

It may be that I'm not quite getting low enough temp.

brian


Offline dab147315

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Re: L45-15 likely bimetal for GE SxS?
« Reply #1 on: July 15, 2013, 03:18:06 PM »
Do you have cooling problem?

Offline archibald tuttle

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Re: L45-15 likely bimetal for GE SxS?
« Reply #2 on: July 15, 2013, 03:27:32 PM »
only as is caused by having no defrost and no circulation through the evaporator.

I know the bimetal isn't closed but I'm not convinced what's going on with the thermistor that switches defrost off either because I get infinite ohms on J1 4-5 which the GE diagrams for the WR55X10942 board say should vary between 80 and 6.6K ohms depending on the box temp. between warm room and 0-15 when cold.

Until I get a bimetal in that I'm sure will close at normal working temps though, I can't really tell if the motherboard is tripping the defrost on or not and the thermistor is only labled as turning it off, not turning it on.  there is no way to trigger or log defrost events that I know of other than let it run a day or two and see if it's completely iced up.

thanks,

brian

Offline dab147315

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Re: L45-15 likely bimetal for GE SxS?
« Reply #3 on: July 15, 2013, 03:44:17 PM »
http://www.appliancepartspros.com/ge-defrost-limiter-thermostat-wr50x10068-ap3884317.html


This is the probably the part # that you should have if you have that board part #WR55x10942 in there.It has a high rating of 140 degree F.If you have a lower one you have the wrong defrost thermostat in there.

Offline dab147315

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Re: L45-15 likely bimetal for GE SxS?
« Reply #4 on: July 15, 2013, 03:52:23 PM »
That type of defrost thermostat rated like your taking about is used in older refrigerators with no boards.

Offline dab147315

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Re: L45-15 likely bimetal for GE SxS?
« Reply #5 on: July 15, 2013, 04:00:03 PM »
Also under manuals on the top you can down load a manual 31-9072 in the refrigerator section on page 5 to get a idea how this ref. works.

Offline archibald tuttle

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Re: L45-15 likely bimetal for GE SxS?
« Reply #6 on: July 16, 2013, 08:53:21 AM »
http://www.appliancepartspros.com/ge-defrost-limiter-thermostat-wr50x10068-ap3884317.html


This is the probably the part # that you should have if you have that board part #WR55x10942 in there.It has a high rating of 140 degree F.If you have a lower one you have the wrong defrost thermostat in there.


That type of defrost thermostat rated like your taking about is used in older refrigerators with no boards.

I noticed on the sticky thread about GE board driven SxS that folks were talking about a 140 high limit.  I assume that the bimetal is now really just a hilimit safety not normal operating control and the evap thermister is the control?  and regardless of the high side I would think the 30 is a surer reset.

This 45-15 was put in last year.  Probably was what the guy had in the truck.  It may be a total coincidence but the fridge functioned fine through the winter months.  Perhaps the combination of high humidity, high temps and more access during summer means longer cycles that worked this thermostat more tripped it off and I don't know if the low limit can move on these very easily or if they are just accurate until they dont work.  not a metalurgist -  that's next month's specialty to learn.

and speaking of specialties, from the sticky on GE SxS evap fan and board issues,
http://appliancejunk.com/forums/index.php?topic=9940.0
I derive that the evap thermister is supposed to be connected across J1 pins 4 to 5.  So I unplugged the J1 connector and check ohms and get infinite.  there are wires connected to those pins but they don't seem to correpsond to the wire colors at the thermistor in the box and I don't know where to look for an onboard wiring diagram although I can check the manual listed in the previous post or any suggestions? thanks,

for any help identifying the model /setup I've attached picture of interior.  sorry it ain't the best but you can see both the evap in the freezer and the controls at the top of the fridge box.

the controls seem to be typical analogy temp settings.

I also get infinite ohms across the pins on J1 that are supposed to be the thermisters for the fridge and freezer boxes, so I'm suspecting that the wiring is maybe not as specified in the diagram.  can't imagine all those thermisters would be bad when the fridge has been running fine until we hit this defrost issue.  But I'm perplexed as to why I can't seem to access anticpated ohm readings as the board seems to anticpate thermisters on those pins and those are the pins that wires are connected to.  maybe I should be measuring to the 5V common which is on another connector but to say I'm confused would be putting it mildly.  A diagram of the wiring and possible wire colors would be a help.

So thanks for the part number and temp range.  I anticpate just getting one of these and seeing if the fridge works in which case I'm not going to beat myself up over not being able to properly ohm the thermisters but I remain your perplexed correspondant.

brian

Offline dab147315

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Re: L45-15 likely bimetal for GE SxS?
« Reply #7 on: July 16, 2013, 09:16:03 AM »
J1 pin 4 and 5 you should get a reading  if open bad evaporator thermistor.Thats the thermistor on top of the evaporator.You can cut it out and test it in a cup of ice and a little water with your ohm meter on the right scale and you should get about 16k ohms.If your meter is on wrong scale you will get wrong reading .I guess you got some reading from the other thermistors and the evaporator thermistor is not showing a reading.How about that heating element does it show some ohms.

Offline dab147315

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Re: L45-15 likely bimetal for GE SxS?
« Reply #8 on: July 16, 2013, 09:20:14 AM »
And yes it is just a safety thermostat.

Offline dab147315

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Re: L45-15 likely bimetal for GE SxS?
« Reply #9 on: July 16, 2013, 09:27:57 AM »
http://www.appliance-repair-it.com/refrigerator-thermistor.html


How to test thermistors this may help you.

Offline archibald tuttle

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Re: L45-15 likely bimetal for GE SxS?
« Reply #10 on: July 16, 2013, 10:11:48 AM »
J1 pin 4 and 5 you should get a reading  if open bad evaporator thermistor.Thats the thermistor on top of the evaporator.You can cut it out and test it in a cup of ice and a little water with your ohm meter on the right scale and you should get about 16k ohms.If your meter is on wrong scale you will get wrong reading .I guess you got some reading from the other thermistors and the evaporator thermistor is not showing a reading.How about that heating element does it show some ohms.

thanks for note.  no, I'm showing infinite resistance across all the thermistors according to the pin out chart for the J1 connector. so I think I am not ohming across the right common wire maybe, as I think it is pins 2 thru 4 are the individual returns and 5 is supposed to be common, but since I'm getting infinite resitance from 5 to 2, 5 to 3 and 5 to 4 something macro must be up, not all bad thermistors is my guess unless some transient current could have melted them all in one fell swoop or something, but the fridge has been cooling fine so I think there is simply something wrong with my checking method although I tried all scales on my ohm meter and judging from the range in the table a 20K would be under but maybe show something depending on box temp or 200K ohms scale ought to be in the ballpark for most of the expected readings.


i feel like something is up with this testing protocol since I'm getting bad readings on all thermistors and the thing was working fine up until it frosted up. 

don't know of any macro electrical events that caused damage to anything else in the house and the board has no physical signs of damage or heating.  my current course of action will be to replace the bimetal and see if it works although I remain perplexed about the ohm readings and haven't been able to find a wire diagram beyond the helpful pinouts for the board posted on the GE SxS evap thread.
http://appliancejunk.com/forums/index.php?topic=9940.0

brian

Offline dab147315

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Re: L45-15 likely bimetal for GE SxS?
« Reply #11 on: July 16, 2013, 10:31:01 AM »
Yeah J1 pin 5 is common to all and thats were you put the black lead of your ohm meter and leave it there to check the others and the colors of the wires in the J1 don't matter just the positioning.Are you unplugging the J1 plug then using your meter.It would be unlikely that all thermistors are bad.I guess you saw the video at the other link i posted on testing thermistors?Maybe meter is bad or your not getting good connection i don't know want to tell you at this point.

Offline dab147315

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Re: L45-15 likely bimetal for GE SxS?
« Reply #12 on: July 16, 2013, 10:53:44 AM »
Also if your going to buy the defrost thermostat you may want to buy a thermistor and change the evaporator one as the thermistor is cheap to buy or you could also cut out the evaporator thermistor and direct test it with the ohm meter and at room temperature you should get about 5 thousand ohms and you could also reinstall afterwards.Also then use the ice bath to see if it raises to 16 thousand ohms.

Offline dab147315

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Re: L45-15 likely bimetal for GE SxS?
« Reply #13 on: July 18, 2013, 10:15:18 AM »
Let us know what happens with this.


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Offline dab147315

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Re: L45-15 likely bimetal for GE SxS?
« Reply #14 on: July 22, 2013, 07:54:56 AM »
Still waiting. I gave my time to help you at least post what results you had.


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Whirlpool defrost bimetal

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