Forums | Home Repair | Home Improvement | Painting | Interior Decorating | Remodeling | Landscaping


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 07-24-2009, 08:05 PM   #1
Newbie
 
Join Date: Jul 2009
Posts: 12
Share |
Question

Attic Fan Runs Slow


I have replace the motor on our attic fan (like a whole house fan) because the old one started running only on one slow speed. After mounting and wiring in the new one it still runs on only one slow speed. When I've bi-passed the switch it makes no difference. It was a solid-state 2 speed switch. Can anyone help? Wouldn't bi-passing the switch make it run on it's highest speed???
kcarrier is offline   Reply With Quote
Old 07-24-2009, 08:33 PM   #2
Member
 
Join Date: Oct 2007
Posts: 2,294
Default

Attic Fan Runs Slow


You should have checked the supply voltage befor you replaced the unit.

Low voltage = slow speed. Could be a wiring issue....could be other issues.

Get a voltage tester or call somebody
220/221 is offline   Reply With Quote
Old 07-25-2009, 02:11 PM   #3
Newbie
 
Join Date: Jul 2009
Posts: 12
Unhappy

Attic Fan Runs Slow


Check the voltage and I have 110 coming in like I'm supposed to. Any other ideas???
kcarrier is offline   Reply With Quote
Old 07-25-2009, 03:30 PM   #4
Idiot Emeritus
 
Join Date: Mar 2008
Location: Fernley, Nevada (near Reno)
Posts: 1,496
Default

Attic Fan Runs Slow


If the motor has two brown (usually) wires going to a capacitor (round or oval thing about 2-3" long), then it's a PSC (Permanent Split Capacitor) type.

A bad capacitor will cause a PSC motor to run slow.

Rob
micromind is online now   Reply With Quote
Old 07-25-2009, 03:37 PM   #5
Newbie
 
Join Date: Jul 2009
Posts: 12
Unhappy

Attic Fan Runs Slow


I got a brand new capacitor with the new motor. I found an online source that says it is the right size capacitor for that motor. Yes, it does have 2 brown wires running to it. The guy who sold me the motor said either wire could run to either side of the capacitor, but not the same side. Was he right?
kcarrier is offline   Reply With Quote
Old 07-25-2009, 05:43 PM   #6
Member
 
Join Date: Jun 2009
Location: Far Southern Illinois
Posts: 47
Default

Attic Fan Runs Slow


Did you perform your voltage check under load?
KeithM62948 is offline   Reply With Quote
Old 07-25-2009, 09:36 PM   #7
Idiot Emeritus
 
Join Date: Mar 2008
Location: Fernley, Nevada (near Reno)
Posts: 1,496
Default

Attic Fan Runs Slow


One of the brown wires goes to one side of the capacitor, the other one goes to the other side. AC capacitors are not polarity sensitive, so it doesn't matter which one goes where.

Is this fan direct drive, or belt drive?

As stated above, was the voltage tested with the motor running? And as close to the motor as safely possible? And tested hot to neutral (not hot to ground)?

Considering that two motors behave the same way, the problem is most likely not associated with the motor.

Rob
micromind is online now   Reply With Quote
Old 07-26-2009, 10:26 AM   #8
Newbie
 
Join Date: Jul 2009
Posts: 12
Default

Attic Fan Runs Slow


Ya, it's been a real mystery. The new motor came with 3 wires (a black, a white, and a red). However, there is only black and white leading to it. The people that sold me the motor said to wire nut the red one and just wire up the black and white like normal. Should the red be wired up somehow too??? I would have NO idea why I would suddenly have low voltage. I didn't check it while the fan was running, so I might try that. A few years ago the fan worked just fine, then one spring it would only run slow. After bi-passing the switch and seeing it still run slow I (and everyone else giving me advice) assumed a winding was bad in the motor. Maybe I just need to call an electrician to figure out what on earth is going on.

By the way, thanks for all the helpful advice everyone has given!!!
kcarrier is offline   Reply With Quote
Old 07-26-2009, 11:01 AM   #9
Member
 
Join Date: Jun 2007
Posts: 3,502
Default

Attic Fan Runs Slow


Run a temporary power cord up there and see if a new source of power corrects the problem. If you do not have a meter. You never have told us the voltage or anything else about the motor. Did you ever see the nameplate?
J. V. is offline   Reply With Quote
Old 07-26-2009, 01:19 PM   #10
Idiot Emeritus
 
Join Date: Mar 2008
Location: Fernley, Nevada (near Reno)
Posts: 1,496
Default

Attic Fan Runs Slow


This is a two-speed motor. White is always the neutral. Black and red are the two speeds. Look on the nameplate, it should state which is high and low.


As stated above, hook it up (temporarily) to a known good source. White to the neutral (the wide slot of a cord or receptacle) and high speed to the hot.

If you don't know which color is high or low, hook one of them up to the hot, and note the speed. Next hook the other one up. It'll be obvious. Be careful, the unused wire will be hot. It must be insulated.

This is a ways out in left field, but check the voltage on the motor. I doubt that this is the problem, but if the new motor is 230 volts and 115 is applied, it'll run a fan at about 30% of normal speed.

Rob
micromind is online now   Reply With Quote
Old 07-26-2009, 02:33 PM   #11
Newbie
 
Join Date: Jul 2009
Posts: 12
Default

Attic Fan Runs Slow


I will have to completely dismantle the mounting to see the wiring diagram plate again. I can do that, though. I think the problem is one of two things (or both). I suspicious the red wire is "high". Without that hooked up all I run on is low speed (which actually could be the case). I could also have a switch problem...a solid-state two-speed switch. I will go back and review the literature that came with it. Thanks for the helpful tips!!!!!
kcarrier is offline   Reply With Quote
Old 07-26-2009, 08:44 PM   #12
Member
 
Join Date: Dec 2008
Location: Dayton Ohio Area
Posts: 670
Default

Attic Fan Runs Slow


I doubt it is the switch. Switches are generally on/off and have no ability to reduced the voltage.
__________________
-Andrew
DIY hobbiest
AndrewF is offline   Reply With Quote
Old 07-27-2009, 08:49 AM   #13
Newbie
 
Join Date: Jul 2009
Posts: 12
Unhappy

Attic Fan Runs Slow


I give up. I've called an electrician.

If it's a voltage issue it's over my head anyway.
kcarrier is offline   Reply With Quote
Old 07-28-2009, 11:25 AM   #14
Member
 
Join Date: Jun 2007
Posts: 3,502
Default

Attic Fan Runs Slow


Quote:
Originally Posted by kcarrier View Post
I give up. I've called an electrician.

If it's a voltage issue it's over my head anyway.
Good call. Everyone cannot be an electrician. To bad you could not follow the simple steps we provided. I know you could have fixed your problem. I would have put money on it.
J. V. is offline   Reply With Quote
Old 07-28-2009, 12:27 PM   #15
Newbie
 
Join Date: Jul 2009
Posts: 12
Angry

Attic Fan Runs Slow


I could be sick!!! The main problem was that the belt was too loose. I know it needed some slack, but I guess where it was allowed too much. The electrician did rewire it to the switch like it was supposed to be...but that really stinks!!!
kcarrier is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Raccoons in the attic electricpete Pest Control 17 05-12-2011 04:02 AM
Recently Topped Up Attic with Blown Insulation...Now I have Frost/Condensation earthad1 Building & Construction 81 02-18-2011 12:42 PM
Attic Fan AND Whole House Fan PapaGnome HVAC 6 02-15-2009 02:28 PM
Attic Smell from A/C - I'm at wit's end! cidsamuth HVAC 17 09-06-2008 12:59 PM
moving wiring runs in attic DoubleD07 Electrical 1 07-23-2007 06:44 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.