Furnace Power vent motor issue. Wiring diagram??

JD Seller

Well-known Member
I bought a Dayton propane hanging propane furnace for my son's garage. It had a cracked heat exchanger. I fixed that issue. The trouble I am having is the power vent motor. It had been unwired when the furnace was taken out of service. I know where it gets hooked into the furnace controls for it to cycle correctly. My issue is that motor wiring. It is a small (1/12 HP) permanent magnet motor. It has four wires coming out of the motor. Two red wires and two black wires. The wires have zero marking on them other than the gauge size. They all have been stripped. They all are the same length. I have tried looking for a wiring diagram on line with little luck.

Here is the motor model and serial number.

Brand: Magnetek

Mod- JB1S005NV

Serial- 42G 12313R

1/12 hp

single phase

3000 RPM

2.2 amp


120volt

I tried looking on Grainger's site under the furnace and the motor both. There is a site for Magnetek motors but they seem to be heavy equipment motors not fractional motors. There seems to be a Century line of motors called Magnetek as well but I can't find one this size on their site.

This motor just runs a small cage fan to blow the fumes out the vent pipe.

I am stumped on this motor. I have tried just about any combination on the four wires and do not get anything out of it.

Anyone know what the wiring MIGHT be????
 
Grainger seems to handle the dayton furnaces you are talking about.

Grainger owns dayton furnaces. See link below for contact info.
 
My "guess" would be the black wires are the line leads, the red wires are the capacitor leads. Might try ohming them out, see if there is continuity between the 2 black leads, and between the 2 red. If they are open, it's not going to run.

Be sure the high limit switch stays in circuit with the gas valve! It has to be there to shut down the flame if the blower fails.
 
Two of the wires MAY come from a normally-open switch closed when the motor is up to speed.

Switch closure = motor/vent running = burner can now fire.
 
Thank you for the reply. Grainger no longer makes this furnace. They also do not seem to have any online manuals for it or the power vent.

Grainger seems to have very little information on this furnace on line other than a general spec. sheet on it.
 
I did some research... if it HAS in internal switch to indicate it's running, likely that is connected to the red wires.

Check for continuity between the red wires... if there is none, likely they are connected to an NO switch that closes when the motor comes up to speed.
 
Bob you have been a big help. My son took the end cap off the motor. The two red wires are to a switch that cuts out when the motor comes up to full speed. Until you posted about that being a possibility we where trying to use the red wires in some combination to run the motor.

The two blacks are just the 120 volt motor supply wires. With the motor apart he blew out a bunch of dust and dirt. The motor was turning free before so it was not dragging but the dust must have been effecting the magnetic fields. With it cleaned out the motor will start and run just fine now.

The red wires are not able to be used on this stove. They really are not needed. The gas/pilot valve is powered through a "blocked" vent switch. If the blower motor does not stop this switch will shut the burner down.

So it looks like the $50 I spent on this stove at an auction is going to be money well spent. I may have $25 in fixing the cracked heat exchanger. I did have to buy some thinner stainless steel to use there.

So Thanks and have a Merry Christmas!!!
 
Magnatec is now owned by "UNIVERSAL MOTORS" outta St Louis, MO.

I have an old Magnatec motor catalog from years ago and I will try to check-out the diagrams in the back of the book.

Also you can call GRAINGER's 800 "help" phone number located in their catalog.

John,PA
 
It looks like you've got the wiring taken care of, but I wanted to mention that even if you can't find info online for Grainger products, I'd try calling their tech support number. They have been very helpful in the past for me as far as researching, calling back, walking through troubleshooting, etc., even on long out of date products. You don't see that level of service too much anymore.
 
I tried.

Checked out the 1990 Magnetec Catalog. Your particular motor was made as an OEM. Magnetec says to contact the manufacturer of the equipment, and, they should be able to provide their application "wiring diagram" for the product.

So, Grainger can probably provide a diagram from their archives. Call them on their 800 number, sometime.


HTH John,PA
 

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