I have a Lennox 10 ACB Compressor system. I noticed today that the Air
compressor (external) was making a humming sound and the fan was not
working. The rest of the Air Conditioning system seems to be working
Any suggestions on how to resolve the above issue.
Fan motor is not working. Could be the motor, could be a capacitor, could
be a few things. If you don't know how to diagnose that stuff, call a
service tech. Check out the service manual here
I'm guessing the start capacitor is kaput.
1. Turn off power.
2. Take several pictures of wires connected to capacitor(s)
3. Remove capacitor.
4. Take capacitor to A/C parts store and say "Gimme one like this"
(Higher voltage okay)
5. Install new capacitor
6. Turn on power.
7. Does it work?
7a. Yes, you're done
7b. No, call reputable A/C tech
You may have a breaker that is tripped, and the relay ( contactor ) is
making a humming noise. ( Note: The contactor is powered from the
inside unit.) If the compressor is buzzing it will cycle on and off.
Check the breakers. You could have one inside the house and one out
side. The one outside may be a fuse type.
The rest of the system could not be working fine if the outside fan
was not blowing air over the condensing coils to liquify the
refrigerant before sending it back to the A-coil in the blower unit
inside the house. That is assuming you have a conventional system.
If it is buzzing all the time, like I said before it may be the
contactor relay. I remember on several ocassions that I found a bug
smashed between the contacts. Again make sure that there is power to
the outside condenser unit. A split unit control circuit voltage
useualy comes from the inside unit.
When our Lennox did this a couple of years back, it was the capacitor;
more precisely, it was one of the two capacitors in a single can. I had
a meter that allowed me to check it; if you don't, maybe you could just
remove the capacitor (take careful note of the connections) and take it
to an a/c service place and see if they will sell you a replacement.
Don't remember how much I paid, but probably less than $20.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.