Lennox G14

Reply

  #1  
Old 01-06-13, 09:28 AM
Member
Thread Starter
Join Date: Feb 2012
Location: Usa
Posts: 2
Upvotes: 0
Received 0 Votes on 0 Posts
Lennox G14

Hi all,

Having some issue with my old, old, old Lennox Pulse G14 (G14Q3-60-1). The furnace started working fine this season, but when I came home on Friday the and turned up the stat the furnace came on, I could hear it because of the infamous pulse, but after a couple of minutes shut back off.

I have done some troubleshooting and have concluded that the blower motor is not coming on, forcing the furnace to shut off when it reaches the internal temperature specified on the fan limit switch.

I am on the verge of just buying a new blower motor, but am a little hesitant. I know all about the Lennox recall on these units and other safety concerns, so I know most people would just tell me to replace the thing already.

I checked the voltages on the unit this morning and it was receiving 120V where power comes in, but was only reading ~90ish volts at the fan limit switch and at the wires going to the blower, so now I'm second guessing myself about the motor.

Other info:
I checked and cleaned the sensor for the heat exchanger, the wire there seemed a little corroded so I stripped it and re-did the connection.

Just to recap, the furnace, induction motor, everything seems to be running fine until the point the blower should kick on to distribute the hot air through the house, which never happens forcing the furnace to shut off.

Thanks for any and all help!

Trying to Stay Warm in Syracuse,

SUforYou
 
Sponsored Links
  #2  
Old 01-06-13, 09:33 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 51,849
Received 255 Votes on 240 Posts
You are probably reading 90ish because you are most likely reading the resistance of the blower motor if you are measuring across the limit switch.

You need to place your probes on the actual wires to the blower and see if you get 120 volts when the limit switch calls for the blower.

Do you have a FAN ON position on your thermostat ?
Does the blower work with that switch ?
 
  #3  
Old 01-06-13, 09:38 AM
Member
Thread Starter
Join Date: Feb 2012
Location: Usa
Posts: 2
Upvotes: 0
Received 0 Votes on 0 Posts
I do have the fan on switch, and have tested it. It does not turn the fan on.

I was pretty confident the blower motor needs replacing but started second guessing myself when I put the volt meter to different parts of the circuit. Is there anything I can do to verify?

I also started reading that the blower would need calibration? Is this true or can I just pull it out and replace the motor?
 
  #4  
Old 01-06-13, 09:57 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 51,849
Received 255 Votes on 240 Posts
A replacement blower may need calibration if it's not 100% identical to the old one.
With the way they constantly sub parts you are almost assured not to get the identical motor you have now.
The heat rise on those units is critical so the fan speed may have to be reset for the application.

You need to locate the actual wiring to the blower motor. You need to check from white(which should be neutral) to whatever color wire they are using for the speed selection. Could be red or yellow.
That blower motor also uses a capacitor which could be bad.
 
  #5  
Old 01-06-13, 03:55 PM
hvactechfw's Avatar
Member
Join Date: Jan 2011
Posts: 6,245
Upvotes: 0
Received 0 Votes on 0 Posts
PULSE FURNACE heat exchangers SHOULD be PRESSURE CHECKED by a LENNOX certified professional EVERY YEAR. They are a POSITIVE PRESSURE heat exchanger. This means that IF a leak develops it WILL put CO (carbon monoxide) into your home. BEFORE spending ANY money on repairs for this type of furnace (parts are becoming VERY hard to find) I would consider replacement and would definitely have it checked by a LENNOX certified PRO.
 
Reply

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


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