wiring an HVAC blower (pictures)

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Forum topic by HokieMojo posted 07-10-2010 05:04 PM 4796 views 0 times favorited 3 replies Add to Favorites Watch
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2103 posts in 3149 days

07-10-2010 05:04 PM

Well, I can’t believe my fortune. I thought the wiring diagram was completely covered in oil and dirt. turns out it was just the installers business label. I checked the other side of the unit, and there was a wiring diagram, as plain as day. the label indicates that the fan is a 120V unit. I think my only questions left are about whether the 3 loose wires I have are all I need to wire it up to power. Here are some photos.

This is the unit.

Here is the capacitor (I understand this is used during start-up?)

Here is a closer shot of the motor itself with the wires coming out.

Here is a shot of the wiring diagram. This was hard to get a good zoom shot of. hope you can read it.

So my questions are:
1) are the 18 ga wires really all that is required to power the motor?
2) if black is usually hot, and white is usually neutral, does that mean my red it a ground? I don’t think this was a variable speed unit. My house is just not that fancy. (-;

3 replies so far

View lew's profile


11264 posts in 3176 days

#1 posted 07-10-2010 05:47 PM

As I read the diagram- “cap off red lead” means do not connect the red lead to anything. Put wire nut on the red lead and then the wire nut securely so it cannot come off. Some furnace blower motors have wires for different speeds. I am not sure if this is the case here.

I wouldn’t use anything less than 14 gauge wire.

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View HokieMojo's profile


2103 posts in 3149 days

#2 posted 07-10-2010 09:13 PM

Ok, I’m not too bright. Thanks for the help lew. I know what to do now. I kept looking at the section off to the right showing the incoming power and never noticed the part at the bottom labeled “MOTOR”. I appreciate it!

View Jim Finn's profile

Jim Finn

2390 posts in 2342 days

#3 posted 07-11-2010 03:15 AM

The 18 guage wire is thermostat wire. You will not be using a thermostat at all.

-- "You may have your PHD but I have my GED and my DD 214"

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