We have an eighteen year old , 80,000 BTU Lennox Pulse Furnace with a 5 ton blower and a 3 ton Lennox air conditioner. Two years ago had it checked (not pressure tested) and was told all was good except replacing a diaphragm.

This year, as we were having the furnace checked for annual maintenance, the tech with 35 years of experiences see that there is "corrosion probably from internal moisture" on what I think he said were contacts near the heat exchanger. I cannot remember exactly, but he showed me with a flashlight and I saw that the pipes with joints all had green color where the contacts meet. I was told that green isn't a good thing and indicates water/corrosion. Then, he pressure tested the heat exchanger. It was "supposed to hold for 10 minutes" and ours barely held for 2 minutes. He did it twice. Both times failed. At this point, the tech says the internal corrosion is a moot point, and most importantly the pressure test failed.

I have had CO detectors for years without any CO alerting us. Tech said that it would be okay to continue to use it but only briefly and to get a new furnace asap, esp. with the problems Lennox has had in the past with heat exchangers. He cannot get a new Lennox heat exchanger for us.

The tech's company sells many brands - not pushing one in particular. We had 5 different sales people offering all kinds of bids for all kinds of furnaces. My husband is thinking of a Bryant modulating 80,000 BTU and a Bryant airconditioner.

My questions:
[B]Are we doing the correct thing to get a new furnace? My neighbor says "my 20 year old Pulse is fine and I've never had it pressure tested" (even though we have had ours 3-4 times in 18 years.) He doesn't want to pay the $400 to do it, and doesn't like the company who performs it - the only company in our town who does - and the one I'm using. I think it's kind of foolish not to check it for $400 but that's up to him. What do you think about that?

Did we do the right thing having it pressure tested?
Would you agree with the tech's recommendation to get a new furnace at his point?
What do you think of Bryant modulating furnace? I also considered a Carrier, but the company's service recond for Carrier (only one in town) isn't that great.
Any negatives that you know about the 80,000 BTU Bryant modulating furnace?

Thank you for your advice and guidance. I can answer more questions - just tried to be brief.

The fancier the furnace the more repair headaches down the road. I basically recommend a simple one or 2 stage unit that gets about 95% efficiency and DOES NOT have a variable speed blower motor. Variable speed blower motors are very expensive to repair/replace.

BTW Carrier is the sister company to Bryant. Most units are the same except for the name change etc.

The fancier the furnace the more repair headaches down the road. I basically recommend a simple one or 2 stage unit that gets about 95% efficiency and DOES NOT have a variable speed blower motor. Variable speed blower motors are very expensive to repair/replace.

BTW Carrier is the sister company to Bryant. Most units are the same except for the name change etc.

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Do you think it is right to be replacing the Lennox furnace if it didn't pass the heat exchanger pressure test twice? As stated above, my neighbor never has had his Lenox Pulse tested in 20 years - just the basic inspection every two years like us. So, how do you know when the exchanger goes bad if the furnace is working and Carbon monoxide detector doesn't go off?

In my opinion, replacing the pulse is a great idea. Quite honestly, they where never a good product to begin with. As far as bryant/carrier goes, I can't say. What other brands were you offered? Goodman, Ruud/Rheem, York, etc, etc? I would shy away from anything with a smart valve, and as far as I know, Carrier is using them these days.