Weil McLain, second wall mounted combi unit leaking.

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.

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.