ApplianceJunk.com

Forum Index => Refrigerator & Freezer Repair => Topic started by: JPG on September 14, 2009, 11:44:27 AM

Title: bi-metal fridge
Post by: JPG on September 14, 2009, 11:44:27 AM
Hi I replaced an open defrost element and it still does not come on. my ques\tion is . This fridge has a thermostat on top and on the bottome of freezer plus a regular bi-metal. The bi-mtal is good are one of the other sensors also another bimetal????? Does this fridge have 2 safety bimeatals??  tks   for your help  JPG

Model gsh25jstass
Title: Re: bi-metal fridge
Post by: JWWebster on September 14, 2009, 06:05:40 PM
JP the ice box uses the plain jane heater and defrost bimetal just like all the old school stuff. But it uses the mother board and a thermister to determine defrost.
Title: Re: bi-metal fridge
Post by: Repair-man on September 14, 2009, 07:22:51 PM
FYI-

A bad evaporator thermister on a GE fridge will make the board skip the defrost cycle
Title: Re: bi-metal fridge
Post by: JPG on September 28, 2009, 02:47:00 PM
Hi Guys, Im still haveing problems with this fridge ive replaced everything except this therimister!!! now which one is it?? Is it the one on top of the evaperator? or on the bottom? Can you just wire the thermister closed?  thanks for your help eventually i will figure out what all these differnt thermisters go.   tks again   joe
Title: Re: bi-metal fridge
Post by: Repair-man on September 28, 2009, 03:00:02 PM
I like to replace both of them, seeing as they are very inexpensive. GE changed them over awhile back to a more dependable product, so it's best to replace them all if you do one in order to keep things working. In most cases, it's the one on top of the coil that causes problems, but don't waste any more time on this repair than necessary and do them both.
Title: Re: bi-metal fridge
Post by: JPG on September 28, 2009, 03:06:00 PM
tks ,   can you just cut out thermister and wire together?? like the bi metal.....   tks again    jpg
Title: Re: bi-metal fridge
Post by: Repair-man on September 28, 2009, 03:16:49 PM
Yep, I use the blue butt-connectors along with some heat shrink, but if you are not picky you can use orange wire nuts. Regarding your earlier question about bypassing them, this will short your board in no time. It reads all 3 thermisters to determine how long the compressor should run and when it should defrost.
Title: Re: bi-metal fridge
Post by: shieldcracker on September 28, 2009, 05:09:44 PM
Do not shunt the thermistors. In general terms thermistors are used as primary controls I haven't seen one used as secondary control. How ever if you have more than one I could see the designer getting away with having the thermistor array act as primary and secondary controls.

A Thermistor will provide feedback to the controller (board ) indicating the state of the evaporator (temperature ) depending on the design this feedback can be used to control the refrigeration cycle the defrost cycle or both, also it can be set to send safety cut out signals. Using more than one thermistor increases accuracy ( provides a truer aproximation of the evaporators state).

Do yourself a favor and replace both (if you have two)
Title: Re: bi-metal fridge
Post by: RegUS_PatOff on September 28, 2009, 06:24:45 PM
... can you just cut out thermister and wire together?? like the bi metal..... 
NO, Thermistors are variable resistors ....