Lennox problems

pharmerphil

I have a 16 year old Lennox Elite model furnace. It quit awhile back, service came out, messed with it and it started. The fan would run, but the furnace would not fire up. They said that the condensation tank was plugged. 11days later it went out again, the diagnoses was the same; However, he showed me what he did to get it going, He removed the lines between the tank and the pressure switches, ran a thick wire into the tank, They blew/sucked on the hoses. Furnace ran! Now, it went down again about 16 days after he left.
I went down and followed the same procedure, It has NOT failed for almost 2 months
They say they need to remove the tank, clean it and reassemble it and a gasket would be needed
Are they trying to get at my wallet, or does any of this seem legit? I/m thinking new pressure switches which I can replace...I will get a model number

pharmerphil

Bump

109A_5

Hello @pharmerphil,
If dislodging the debris from the condensation tank and associated drain hoses has resolved the issue, each and every time, why would it be something else ? The pressure switches probably cycle with each cycle of the furnace. If you truly think it is pressure switch related failure I would start by verifying the connections where the wires connect to the switches are not loose.

Maybe there is a simpler way to flush out the condensation tank debris than disassembly, although disassembly may be the best way to thoroughly clean it.

pedmec

I'm confused. Condensation tank? if you mean condensation trap then just remove it and clean it out. if your talking about the secondary heat exchanger, which is what it sounds like, good luck. you ain't getting that back together. you might be able to get the collector off the front of the furnace but that takes a little time.

pharmerphil

Thanks for your replies I will get a photo today and a model number

pharmerphil

Alright, here are some photos. Like I previously
said, they say this tank (arrow) gets plugged ? They stock a long allen wrench in the hole where the hoses connect (both hoses/both sides) and said that fixed it...But would require them to take it a part to get to the tank and then it would require a 'gasket' to reassemble. It went out and required 3 visits from the repairman. Next time it went out I did what I seen them do, no good, I removed the hoses, checked to see if they were clear, they were. I then took all the hoses off of the tank and blew/sucked on the switches, I could here what sounded like a diaphragm opening and closing, fired it up, Heat! and instead of 11 days between service calls, it's been since January with no problems

Mustangman

I have found that those square tubes off of the pressure switch need to be arranged that condensation can't build up and form a trap in the condensate line.. A few drops of water in those tubes is all it takes to knock the switched out. I won't mention the manufacturer but they shipped a bunch of furnaces out with condensate tubes were way too long and the piping formed a natural trap in the tube. After a few call backs, we realized they had a whole run of 100K furnaces had this problem.
I am nearly ready to retire but as I think about this trade, a lot of what we learn is through the school of hard knocks. The up side to that, you don't forget those lessons you learned in someone's basement at 10PM... and you keep getting that pressure switch fault. HA HA

pharmerphil

Thank You, and I did rearrange the hoses when I worked on it myself

109A_5

Hello @pharmerphil,

Inducer Gasket, 99M77, multiple internet sources with various prices, you would have to confirm compatibility. Maybe you can clean or flush out the collector box. Maybe develop a way to flush out the debris without collector box removal from the furnace.

Are these recent pictures ? Maybe it is the camera angle but those tubes still look like they can trap condensate.




https://www.repairclinic.com/PartDetail/Gasket/99M77/2727705

pharmerphil

109A_5 said:

Hello @pharmerphil,

Inducer Gasket, 99M77, multiple internet sources with various prices, you would have to confirm compatibility. Maybe you can clean or flush out the collector box. Maybe develop a way to flush out the debris without collector box removal from the furnace.

Are these recent pictures ? Maybe it is the camera angle but those tubes still look like they can trap condensate.




https://www.repairclinic.com/PartDetail/Gasket/99M77/2727705

sounds like a plan, I had thought of someway to flush the tank. Yes recent pictures, hoses still need tweaked?