Weil McLain, second wall mounted combi unit leaking.

BenryPA

In 2020 I purchased my current home that had a Weil McLain AquaBalance AB155 which had been installed in 2017. The boiler was leaking at the dhw heat exchanger. There where receipts from installer for attempting to correct the leak. The installer again attempted to stop the leak with no success. Weil McLain agreed to provide a replacement unit. Installer agreed to charge me 50% of installation cost. Fast forward 4 1/2 years and the replacement is leaking at both the primary heat exchanger and secondary heat exchanger. Is the brand just junk or is this common for most condensing combi units? Is there a reliable alternative or go with CI boiler and indirect dhw,

Ironman

There are several good mod/cons: Lochinvar, HTP EFTU are the ones we primarily sell and install. I’d recommend those in a heating boiler + an indirect.

Let me also add that the installer is more important than the brand; he’s 95% of the equation.

You probably have other issues in your system that are causing the premature failures of the heat exchangers. A good tech will find and correct those issues before simply swapping out the boiler.

GGross

Not my preferred brand but a heat exchanger failures generally are more site conditions/install related, than manufacturer defect. it's hard to tell without being there. For example if the system takes on a bunch of untreated make-up water that will greatly increase every brands risk of failure.

tjoyce

I just came across this post. I have the EXACT same leak. I have spent countless hours figuring out where the failure is, with these Aqua balance boilers - and I found it.

First, quick story. My leak was caught in time, and covered under warranty. Weil McLain determined that it was a failed heat exchanger. They sent me a new one, and I installed it.

Curiously, I wanted to find the failure, and I did. There is a red rubber seal that fails, behind this area of the leak. It becomes brittle and cracks. This causes condensate water to - ever so slightly - drip at certain times. However, It doesn't always leak. It leaks only when the boiler has been fired for long periods, like cold weather snaps etc etc. Condensate water is acidic and over the years, this leak soaks the sponge like seal on the back of the cover case, and causes all kinds of rotting issues - exactly like yours.

Now, after 5 years mine is leaking exactly in the same spot again, so I found one online. It is like new, only ran for a few years - says the owner - so I bought it. GUESS WHAT - that one has a tiny leak just starting.

So, after actually seeing 4 different boilers - leaking in this exact same spot - and doing this exact same damage - I can say that without a doubt - The Aqua Balance boiler has a manufacture defect, and should be avoided at all costs. No matter who installs it - this seal will eventually fail. AND, there is NO fix for it, because it is a manufactured defect.

TheUpNorthState88

https://forum.heatinghelp.com/discussion/comment/1887347#Comment_1887347

Yup, that's definitely a manufactured defect. Kinda sad to see how great brands like Weil Mclain are cutting corners these days and just one excuse for me to avoid condensing boilers. I'm just not a fan of them.