Hot Rod Forum banner

LP garage heater; need help from an 110v fan motor guru..

2K views 7 replies 6 participants last post by  matt167 
#1 ·
We moved into our "new" place on the 22nd. I'm trying to get the biggest shop useable. There is an old Reznor LP heater, dated 1940. I have it starting & heating fine, but the blower fan motor fried.

This 75,000 btu heater has a 2 prong 110v plug....never had a ground lug. The fan type has me stumped because it has 3 wires. When designed, the fan comes on when temps get up. But there is also a toggle switch marked "summer/winter". Summer position just made the fan work for cooling. On Winter position, it only would come on if the temp sensor gets hot enough.

My question is: the orig fan has 3 wires going right into the field windings. (I took it apart to make sure). I wonder if the 3 wires are for 2 seperate parts of the windings, to make 2 different speeds for the "summer" or "winter" modes???

I can try to take a pic of the wiring diagram to show how the switches, temp sensor, and everything else. How could I just use a 2 wire modern window fan motor work with the switch in the "winter" position?...so it could come on with the temp sensor?? I don't care if the "summer" mode does not work.

Any ideas? I am going to use a box fan strapped to the heater for the next few days, just to keep working in the shop. But would like to have it temp controlled in the near future. Thanks
 
See less See more
#3 ·
One needs to have a business license to buy from Grainger..but in any case if I had the motor data..nameplate and such I think I could come up with a replacement which in this case I would suggest..Also check around with some of the local guys as there may be someone in the area who understands and works with those heaters..

Sam
 
#5 ·
More than likely the extra wire is for the start windings. Most ac motors rely on an additional set of windings to get the motor spinning in the correct direction. This can be accomplished several different ways, Most larger motors, will use a starting capacitor or a capactior and relay combo. Some, like most bench grinders, have a switch that closes and opens based on motor rpm. It is real common for the capacitors to fail. You may want to look for it and see if it looks burnt. If you can spin the motor by hand and get it to turn it is most likely a start circuit issue. The tip off to this is the motor will generally just hum but if you give it a flip it will work fine until turned off.
If you do need a motor, there are usually lots of places that will either repair of seel you a replacement
 
#6 ·
I forgot to say that there never was a tag on the motor, and no ID or brand info stamped on it anywhere. It only has a paper tag glued on it to remind users of the summer/winter switch.

Looks to be a very small fractional HP motor.

It does not have brushes. The armature does not have windings like a starter motor. The field wiring has a burnt spot with a quite a few wires melted away.

It does not have a capacitor start.

I'll try to put up a pic tomorrow. Thanks
 
#8 ·
OneMoreTime said:
One needs to have a business license to buy from Grainger..but in any case if I had the motor data..nameplate and such I think I could come up with a replacement which in this case I would suggest..Also check around with some of the local guys as there may be someone in the area who understands and works with those heaters..

Sam
just a buisnuess card usually works if it's your name/ place of employment, as long as the company on the buisnuess card don't have an account w/ grainger you just pay in cash.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top