# Need SG379 Thermister for GE motor's "ECM"



## Yoyizit (Jul 11, 2008)

Blackie said:


> Does anyone know where to get a SG379 thermister for my air handler? I have a GE 1HP 120V motor with an ECM 2.3 controller. It appears this is all I need to get my heat back on with my heat pump. I have searched a lot of web sites, but none have this part.
> Thanks
> Blackie


If you can wheedle the specs. on this device from the manufacturer's receptionist you can search for some equivalent thermistor. You probably need the resistance at two temps and whether it a negative or positive tempco thermistor.

I got a small generic lamp for 32¢ for which the manuf. wanted $32 because the customer service lady read me the specs wanting to make sure she was selling me the correct lamp.

Or, if you have a schematic for the electronics that mates with this device, we might reverse engineer it.

Maybe these guys can cross reference it
http://www.ussensor.com/pgthermistors.html?gclid=CPeWhI7P2pgCFQw9GgodgndLcw
If you say you need it to build an engineering prototype they may send you a free sample of the correct device.


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## beenthere (Oct 11, 2008)

120 volt air handler???


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## hvaclover (Oct 2, 2008)

Yeah and 1 HP too? Must have the voltage wrong.


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## bob reynolds (Oct 9, 2008)

*SG379 available at Amazingkeys.com*

Amazingkeys.com has the SG379 thermister.


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## FSUDAL (Aug 3, 2012)

*Sg379 for $2.36*

I know this thread is old but during my research I could not find the answer to my question (where can I get the SG379 or a suitable alternative for a fair price) so I am positing this information about how I resolved my issue. I contacted RTI Electronics (manufacturer of the SG379) and got the specs for the SG379. It's a 1ohm 30amp Inrush Current Limiter. Same as their SG405 or the more readily available SL32 1R030 from Ametherm. I bought the SL32 1R030 from Newark for $2.36 and $6.22 shipping. Received in two days. Just swapped out the faulty component two hours ago and am now basking in the cool air once again. Can't believe a $2 part saved me from spending $1000. I had an HVAC tech come out to confirm the problem before attempting to fix ("easter egging" on your own is not safe), signed up for their service plan for $236 (includes free troubleshooting and two service visits for routine maintenance. I will now have them back to check over the system as part of the plan. Working on an HVAC system is dangerous and I would not recommended it to anyone. I was an electronics tech in the Marine Corps and had help from a licensed HVAC tech. Stay safe, get help. You can still save a bundle. As a side note I also purchased the VZPRO surge protector (Zebra Instruments) for my GE motor since the motor and motor module is so incredibly expensive. It connects between the motor and OEM connector. Next time I can just swap out the VZPRO instead of soldering in a new component.


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## YADIYER (Apr 4, 2019)

FSUDAL said:


> *Sg379 for $2.36*
> 
> I know this thread is old but during my research I could not find the answer to my question (where can I get the SG379 or a suitable alternative for a fair price) so I am positing this information about how I resolved my issue. I contacted RTI Electronics (manufacturer of the SG379) and got the specs for the SG379. It's a 1ohm 30amp Inrush Current Limiter. Same as their SG405 or the more readily available SL32 1R030 from Ametherm. I bought the SL32 1R030 from Newark for $2.36 and $6.22 shipping. Received in two days. Just swapped out the faulty component two hours ago and am now basking in the cool air once again. Can't believe a $2 part saved me from spending $1000. I had an HVAC tech come out to confirm the problem before attempting to fix ("easter egging" on your own is not safe), signed up for their service plan for $236 (includes free troubleshooting and two service visits for routine maintenance. I will now have them back to check over the system as part of the plan. Working on an HVAC system is dangerous and I would not recommended it to anyone. I was an electronics tech in the Marine Corps and had help from a licensed HVAC tech. Stay safe, get help. You can still save a bundle. As a side note I also purchased the VZPRO surge protector (Zebra Instruments) for my GE motor since the motor and motor module is so incredibly expensive. It connects between the motor and OEM connector. Next time I can just swap out the VZPRO instead of soldering in a new component.


I realize this is an old thread; however, since this was the _only_ google search result that was related to my inquiry, thought I might as well post and hope for a reply.

Looking at the Zebra VZPRO it seems to essentially be nothing more than an Inrush Current Limiter (like in the ECM motor module itself) just put into a plastic casing with the necessary bits of wiring/connectors to connect it inline between the power harness and the motor. If that's the case, wouldn't it be easy enough to buy the correct thermistor (not sure if they're using another SG379/SG405/SL32 1R030) and connectors then wiring it up inside an appropriate plastic casing? Any thoughts on this or has anyone actually tried it instead of paying the roughly 35 bucks for the EZPRO?


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## supers05 (May 23, 2015)

YADIYER said:


> I realize this is an old thread; however, since this was the _only_ google search result that was related to my inquiry, thought I might as well post and hope for a reply.
> 
> Looking at the Zebra VZPRO it seems to essentially be nothing more than an Inrush Current Limiter (like in the ECM motor module itself) just put into a plastic casing with the necessary bits of wiring/connectors to connect it inline between the power harness and the motor. If that's the case, wouldn't it be easy enough to buy the correct thermistor (not sure if they're using another SG379/SG405/SL32 1R030) and connectors then wiring it up inside an appropriate plastic casing? Any thoughts on this or has anyone actually tried it instead of paying the roughly 35 bucks for the EZPRO?


Half of that price is certification for that assembly. Other than that, go nuts. Since there's other sensitive electrical components in a furnace and /or ac/HP, I'd recommend a surge protector for the whole thing if you can have the money for one.


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## YADIYER (Apr 4, 2019)

supers05 said:


> Half of that price is certification for that assembly. Other than that, go nuts. Since there's other sensitive electrical components in a furnace and /or ac/HP, I'd recommend a surge protector for the whole thing if you can have the money for one.


If it even is certified. I didn't notice a UL or any other certification logo in any photos I saw of it. As for protecting the whole unit, I did consider the Intermatic AG3000 but read several reviews/posts about them not honoring the protected equipment warranty they advertise for it. And I'm not keen on supporting companies that push their products with those sort of promises but then don't stand behind them. Since I'm now putting in the 3rd new ECM blower motor (due to the typical motor being OK but the module failing) it seemed the added protection for that specific part of the system was a good idea if it could easily be made for just a few dollars in parts. Which resulted in me finding this topic and wondering if anyone else had already discovered what thermistor they are using in the EZPRO.


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