Home & Garden

Furnace : Lennox 90ugf, not turning on

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  • Oct 5th, 2020 3:40 pm
[OP]
Deal Addict
Sep 12, 2017
1816 posts
175 upvotes

Furnace : Lennox 90ugf, not turning on

Who is best to call for service, furnace is not running on. Is Enbridge best, is everyone have the same rates to fix?

The furnace is about 15 years old. It tries to turn on and then it stops. It has fast alternating flashing lights:

Lights mean the following:

IMPROPER MAIN GROUND OR LINE VOLTAGE BELOW 75 VOLTS, OR BROKEN IGNITOR, OR OPEN IGNITOR CIRCUIT.

Also being winter should I be looking into getting electric or other heaters to provide warmth for the home?
14 replies
Jr. Member
Nov 2, 2015
180 posts
138 upvotes
Oakville
You wouldn't want to call Enbridge they are gas distributor not service or installation people. You can look for reputable HVAC companies in your area. If you're in my area I can certainly help which is GTA West. Most rates are $99 to get a technician to the door, the rest is if parts are needed and labor to repair the unit.
Deal Addict
Feb 25, 2007
2626 posts
442 upvotes
did you check if your drain line is clog? That's usually the most common thing when it fires up and shuts down because of the water in system
[OP]
Deal Addict
Sep 12, 2017
1816 posts
175 upvotes
I'm in Bolton Ontario. Do companies specialize in Lennox units? This one is about 15 years old.
Jr. Member
Nov 2, 2015
180 posts
138 upvotes
Oakville
Most companies are able to repair all types of furnace problems. Just look for one with decent reviews around you. If your furnace is starting up for a few seconds and you see flames then shuts down like described you may have a clogged drain or the flame sensor is dirty. These are two easy DIY options to repair if you want to save some bucks. If your igniter is gone you'll need a technician likely to purchase a new one and install it, though I have heard of homeowners getting their hands on them before. It's likely anyone you talk to will ask if you want to replace the furnace entirely due to age and putting money into an older system.
[OP]
Deal Addict
Sep 12, 2017
1816 posts
175 upvotes
JivesHVAC wrote: Most companies are able to repair all types of furnace problems. Just look one with decent reviews around you. If your furnace is starting up for a few seconds and you see flames then shuts down like described you may have a clogged drain or the flame sensor is dirty. These are two easy DIY options to repair if you want to save some bucks. If your igniter is gone you'll need a technician likely to purchase a new one and install it, though I have heard of homeowners getting their hands on them before. It's likely anyone you talk to will ask if you want to replace the furnace entirely due to age and putting money into an older system.
Checked the intake and exhaust, the drain seems to be clear also (blew through it). Not sure about the flame sensor. Next was trying to find a fuse.

I had a similar issue on a newer furnace in another house, it was under warranty. They have replaced the mother board. That job cost $1000. Wonder if it is the same thing. Both furnaces used the same filters 1" MERV 8, though that just may be a coincidence.

Can anyone recommend a reputable HVAC company in the Bolton, area?
Deal Addict
Jun 16, 2009
2490 posts
913 upvotes
Woodbridge
Focus should be on why it is happening rather than what is happening. LED indicators on board are decisive mostly. It can be even your circuit board malfunctioning and giving you wrong error codes ( thank god its not expensive as its for dual stage furnaces) .
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Deal Addict
Mar 22, 2017
1244 posts
1295 upvotes
West GTA
newlyborn wrote: Focus should be on why it is happening rather than what is happening. LED indicators on board are decisive mostly. It can be even your circuit board malfunctioning and giving you wrong error codes ( thank god its not expensive as its for dual stage furnaces) .
Does a dual-stage furnace actually save homeowners money, after you account for the high upfront cost and high maintenance cost? Or is it just for comfort due to longer, lower intensity cycles?
Deal Addict
Jun 16, 2009
2490 posts
913 upvotes
Woodbridge
It is hard for me to compare for myself as when I changed furnace in my own home, I simultaneouly changed my dryer and stove into gas versions. I could never compare real difference in consumtion currently from past.
Lets wait for other RFD's to chime in if anyone ended doing a real comparison of usage.
grumble wrote: Does a dual-stage furnace actually save homeowners money, after you account for the high upfront cost and high maintenance cost? Or is it just for comfort due to longer, lower intensity cycles?
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Deal Addict
User avatar
Jun 13, 2008
1524 posts
577 upvotes
Burlington, ON
I have the same furnace (about 20 years old) and have replaced both the flame sensor and flame igniter, very easy to do yourself. You can see through the glass "peep" hole and look to see if the flame igniter is glowing red when it tries to light (it's on the far right of the three burners). If not, perhaps that's your problem. If it lights off OK, and you see a blue flame and then it shuts off it might be the flame detector.

Link to igniter.

Link to flame sensor.

You might get these parts cheaper on other sites like;

https://www.easyapplianceparts.ca/
https://www.reliableparts.ca/
https://www.partselect.ca/

If your unsure about the part number, just call them and verify.
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Member
Jul 5, 2017
469 posts
871 upvotes
Toronto
anyone with this same furnace (90UGF) happen to know what the two brown wires that connect to the side burner box are? Was fiddling around with the furnace and the plastic part snapped. Wanted to know what the part was before calling someone to come look at it.
Sr. Member
Jan 19, 2013
514 posts
301 upvotes
Ottawa
mikesanity wrote: anyone with this same furnace (90UGF) happen to know what the two brown wires that connect to the side burner box are? Was fiddling around with the furnace and the plastic part snapped. Wanted to know what the part was before calling someone to come look at it.
Rollout switch. Don’t run the furnace without that.
Deal Addict
Mar 2, 2017
1083 posts
852 upvotes
flyboy320 wrote: I have the same furnace (about 20 years old) and have replaced both the flame sensor and flame igniter, very easy to do yourself. You can see through the glass "peep" hole and look to see if the flame igniter is glowing red when it tries to light (it's on the far right of the three burners). If not, perhaps that's your problem. If it lights off OK, and you see a blue flame and then it shuts off it might be the flame detector.

Link to igniter.

Link to flame sensor.

You might get these parts cheaper on other sites like;

https://www.easyapplianceparts.ca/
https://www.reliableparts.ca/
https://www.partselect.ca/

If your unsure about the part number, just call them and verify.
Where is the flame sensor exactly? I look through the glass and see something with two white wires that appears to be going into the burner...is that it?
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User avatar
Jun 13, 2008
1524 posts
577 upvotes
Burlington, ON
Usually the flame sensor has one wire, and the ignition has 2. In my furnace the ignitor and flame sensor are on opposite sides of the burner (one on the left and one on the right when looking through the sight glass).
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Deal Addict
Jun 16, 2009
2490 posts
913 upvotes
Woodbridge
Flame sensor on 90 UGF is behind the air hose that is attached to ventor motor. If you want it to do it properly than you have to unscrew the ventor motor, take the rubbber transition out and than access the sensor underneath the burner box located on left hand side.
sks8100 wrote: Where is the flame sensor exactly? I look through the glass and see something with two white wires that appears to be going into the burner...is that it?
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