Does The Size Of The Blower Motor Matter? - HVAC - DIY Chatroom Home Improvement Forum

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


Thread Tools Display Modes
Old 10-25-2012, 08:48 PM   #1
Join Date: Oct 2012
Posts: 1
Rewards Points: 10

Does the size of the Blower Motor matter?

We were recently informed the bearings in our current motor of the upstairs AC have messed up and this is why the blower fan is not working. The handy man we hired then brought in another motor, but told us after he had already started working that the motor he brought us is 1/2 HP. The original was 3/4 HP. According to him the difference in HP was negligible and we would not notice any difference in how the AC unit cooled the house, nor how fast, how well, and said that this motor would last as long or longer then the original. The Originals was an Emmerson 3/4 HP motor unit with 3.8 AMPS, 1075 RPM, 60 Hz. and 3 speed.
The new was AO Smith MasterFit 1/2 HP motor with 3.9 AMPS, 1075 RPM, 60 Hz. and 4 Speed.

Was the handyman correct?
Or were we correct in canceling the job and looking for another 3/4 HP motor?


Moiz2012 is offline   Reply With Quote
Old 10-25-2012, 09:25 PM   #2
Join Date: Nov 2010
Location: NE Indiana
Posts: 2,426
Rewards Points: 1,208
Blog Entries: 1

you can increase horsepower, to an extent; you can not decrease horsepower.


hvactech126 is offline   Reply With Quote
Old 10-25-2012, 09:34 PM   #3
Join Date: Apr 2011
Location: Chicago, IL
Posts: 48
Rewards Points: 29

It isn't only a question of air movement for the motor. It's also a question of load on the motor turning the fan blades, size and weight of the squirrel cage assembly.
A properly sized replacement motor runs $150-$200, at least around here. Replacement isn't that difficult. I suggest you get the motor sized for your unit.
MarkusAIC is offline   Reply With Quote
The Following User Says Thank You to MarkusAIC For This Useful Post:
how (10-25-2012)
Old 10-26-2012, 04:40 AM   #4
An old Tradesmen
Join Date: Oct 2008
Location: Somewhere
Posts: 34,591
Rewards Points: 8,168

By the amp rating of the 1/2 HP you would be ok. Myself, I wouldn't use it in place of your 3/4 HP though.
beenthere is online now   Reply With Quote
The Following User Says Thank You to beenthere For This Useful Post:
ben's plumbing (10-26-2012)

Thread Tools
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
Bryant Plus 90 - No Blower Ducaticorse HVAC 13 01-03-2015 04:39 PM
Polaris Water Heater Blower TMcCrea HVAC 0 06-10-2012 06:17 AM
Acceptable Blower Vibration John_NH HVAC 15 11-21-2010 12:49 PM
Furnace will not stay on allenzachary HVAC 32 09-21-2010 08:30 PM
Blower cycling and vibration whatshappening HVAC 1 02-09-2010 04:48 AM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1