Fireplace Fan Wiring Question

[TromboneAl]

I have a two-speed fan that blows air through our woodstove-live fireplace. Looks like this:

It's gotten very noisy, and I'm going to replace it.

There are three wires that go to the fan from the switches that control fan speed: black, white, and red.

I'm guessing that the red wire is related to the speed. Can someone explain how that works?

 

[jazz4cash]

What kind of switching are you using?

I am adding a blower to a gas log set in a B-vent chimney. It has black/White/green wiring. The white wiring from 3 prong AC plug goes through a variable speed switch and a temperature switch to the motor. The black wire goes directly to motor. Green wire is ground.

The unit plugs into regular AC outlet and it turns on/off based on the temp switch and variable speed switch.

I got the unit at a place called fireplaceblowers online. They have pretty good support including youtube.

 

[TromboneAl]

The switches are:

1. Low-Off-High
2. Always on Versus on when fireplace is hot

 

[jazz4cash]

The switches are:

1. Low-Off-High
2. Always on Versus on when fireplace is hot

What's the power source?

I guess my unit has the variable speed switch instead of your switch #1.

Your switch #2 is probably a bypass for the temperature sensor and must be in series with switch #1. My temperature sensor has no switch so I don't have the option to run the fan when the unit is not hot (unless I add a bypass for the sensor).

 

[Lakewood90712]

Usually on these little multi speed motors, white wire is the common , black and red are the "Speeds" . I assume the new motor does not have a run capacitor, or if it does, it is already mounted to the motor and pre wired. The new motor will have a diagram on it.

With the motor disconnected , check the ac volt output from each switch terminal going to the old motor. Be safe, getting hung up on 120 volts can easily be fatal.

When you say the old motor is noisy, is it like a bearing noise, or is it shaking ? These squirrel cage blowers can pick up enough lint and dirt over years to become un-balanced.

I'm sure one of the engineer nerds on the board will chime in shortly.

 

[Senator]

Is there any thermostat on the fan? Or will it run cold?

 

[Winemaker]

At low speed does one blower run and the second blower starts at high speed OR does both blowers run and at 2 speeds? If the former, black is power for one blower and red is power for other.

Have you lubed the blower bearings or cleaned the blower blades? Dirt may have put fan out of balance.

 

[427Vette]

Typically on a fractional horsepower motor like that the speed is controlled by the amount of poles energized in the motor. I am guessing it is a four pole motor and the black wire energizes two of the poles so it runs at a slower speed then the red wire energizes all four poles so it spins faster. On that small of a motor you could just wire it on the high speed setting then control it with a fan speed control rheostat to obtain an infinite amount of adjustability.

 

[TromboneAl]

When you say the old motor is noisy, is it like a bearing noise, or is it shaking ? These squirrel cage blowers can pick up enough lint and dirt over years to become un-balanced.

It's bearing noise, as far as I can tell.

Yes, I have to clean all the dust of yearly, or it gets out of balance and rattles.

It started being noisier years ago, but recently it will get really loud for a minute or two periodically. I've done all kinds of lubricating and engaged in percussive maintenance, but nothing shuts it up.

I'm sure the replacement will be much quieter.

 

[braumeister]

percussive maintenance

That's a great phrase!

Maybe you just need a bigger hammer.