Lennox GWB9-100IH-2 Series Q90-100 Leaking

steve_

Backstory:

This boiler was installed in 2007 in a new construction home to support two baseboard hot water zones (first floor, second floor), and an indirect hot water zone supported by a Buderus S120 tank. The plumbing and heating contractor installed as a single loop with one circulator pump with three zone valves (not primary/secondary).

On Christmas Eve 2018, I woke up to a strange sound in the basement and upon inspection, discovered that the (cast aluminum) heat exchanger had sprung leak, spraying directly onto the draft inducer. After working with a local Lennox dealer and coming up with some very creative ways to re-route the growing leak while continuing to run the boiler, the heat exchanger was replaced as it was within the 15-year warranty and installed on January 9th.

Between that heat exchanger replacement and now, we've also replaced the draft inducer, multiple igniters, and the control board.

Fast forward to this year's heating season and as I was doing a once over, I noticed a small puddle of dried crusty water under the boiler. When I poked my head up inside, I found that there is a slow leak at the gasket seal (see photo — this is looking directly up from under the heat exchanger).

I had a Lennox-authorized service tech take a look and his reaction was that we won't last the heating season and need to replace the heat exchanger/boiler. When I contacted Lennox directly, they stated that while the replaced heat exchanger is < 7 years old, the warranty coverage is based on the date of original installation.

At this point I'm very ready to move on to another product altogether if it means leaving these types of problems behind, but have two questions for anyone that might be able to offer advice:

1. Have you experienced anything like this before? If so, is there any hope for this unit? I'm very hesitant to rip the condensate drain out and poke around too much if it could mean that I negatively affect an already bad situation
2. Given the track record that I've had with cast aluminum heat exchangers and a suggestion of a local friend, would something like a Weil-McLain GV90+ be a sensible option as a replacement?

I have not had any trouble with the indirect tank (yet!) and have replaced the anode rod 2x since 2007. I would be interested in replacing that as well if it seems like the right thing to do proactively..

Thank you for reading and Happy Thanksgiving! 🦃

mattmia2

i think, without digging for the lennox manual, that in aluminum hx boilers, you have to maintain an inhibitor in the system to keep the aluminum from dissolving in the hot water.

it is more what the installer knows vs a specific brand but lochinvar, viessman, htp, and a couple others make good boilers. Baseboard isn't really the right emitter to take advantage of the benefits of a mod con boiler. It will work but you are likely getting efficiency in the 80's because the output of baseboard is very low at the low water temps you need to get condensing.

EBEBRATT-Ed

Well, you got 18 years out of it and that is all you're going to get out of a mod con although the hx was replaced.

I don't think I would fix it at this point as it is likely that you would need other parts as it ages and most mod cons parts become scarce after 15-20 years.

I would stay away from aluminum. Buderus/Bosh mod cons were/are aluminum

EdTheHeaterMan

Weil McLain is a decent product if your installer likes them. I didn't when I was in business. I used Crown boilers before they were purchased by US Boiler. (The same folks that make Burnham) I still like Crown boilers. They are assembled in Philadelphia by Velocity Boiler Works and have great customer service and Tech Support.

The brand of the boiler is not as important as the installing company. You need a Contractor that knows the latest and greatest about Hydronic heating. If you get a company that has Bubba installing boilers like his dad did 50 years ago, then he can screw up the best made boiler. Get a good contractor and go with their recommendation. 

steve_

Thanks all for the advice 😊