Condenser fan seems too fast, makes louder hum than before...


  #1  
Old 07-11-12, 08:49 AM
S
Member
Thread Starter
Join Date: Jul 2012
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
Condenser fan seems too fast, makes louder hum than before...

Hello all,

First some background on my issue. I had zero experience in HVAC, but after reading many posts on this forum, I was able to replace my capacitor and condenser fan motor (motor was overheating after 30-60 min of use). I replaced it with a motor of the same type (Fasco D7909 1/4 hp, 1075 rpm) as well as a matching capacitor (50/7.5 mfd, 440 VAC 50-60 Hz dual capacitor). The wiring was a bit difficult since the colors of the old motor did not match the new.

After hooking it up, I was still having issues with overheating on occasion. I realized yesterday that I had the white and black wires backwards, and swapped them. Since then, the motor is definitely working, but seems to be too fast, and is humming louder than before. I could just be wrong about it being too fast, but I definitely think the hum is an issue. Could I have bent one of the fan blades during installation, and if so, how do I test that?

(Edit: I also had an issue with the fan going in the wrong direction sometimes but not all, which is how I figured out that the white and black wires were backwards...)

Thanks in advance, any info would be appreciated. As I said, I am new to this type of maintenance. Sorry for the long post, wanted to give as much info on the issue as I could.
 
  #2  
Old 07-11-12, 05:57 PM
hvactechfw's Avatar
Member
Join Date: Jan 2011
Posts: 5,491
Upvotes: 0
Received 4 Upvotes on 4 Posts
most likely you have the capacitor wired wrong. Please post your wiring to the capacitor.
 
  #3  
Old 07-12-12, 02:37 PM
S
Member
Thread Starter
Join Date: Jul 2012
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thanks for the response hvactechfw. It turns out the fan was just mounted lower than it needed to be, this is what seemed to be causing the extra noise.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: