AB-120C AquaBalance Combination Wall Mount Gas Boiler, 97,000 BTU (NG)

This unit was a great replacement for the previous combi (different brand) The installation and set up was easy. It's only been in for a few weeks but working great.

Works great for about 2 years which, incidentally, is how long the warranty is for most parts. The 10 year warranty is only for the heat exchanger. The biggest issues are the 3 way valve and most internal copper connections. About half of the copper tubing connections in this unit are gaskets secured with a flimsy retaining clip. 2 years and 3 months after purchasing this unit, it already developed a slow leak and needed a gasket replaced. The biggest issue is the 3 way valve: - it's made of plastic as compared to the brass commodity 3 way valve - it's powered by a flimsy motor similar to those found in $10 remote controlled toys - it's secured with a gasket and flimsy retaining clip as opposed to the beefy threading on standard brass 3 way valves - it's contorted into the unit so it's near impossible to replace with a proper brass 3 way (in addition to the connections being non standard) - you can't just replace the motor like you can on a proper 3 way - it's unavailable (at the time of writing), backordered for a month just before winter when you need it. It's in the "off position" all year since it's routing to domestic hot water; turns the motor on when you need to heat your home - Weil-McLain might've saved a couple bucks putting in plastic, but you'll spend $250 replacing it every couple years. The brass one is $350 and is indestructible; the motor might fail but it is $125 and easily replaceable. The worst part is, if you size up for $200, and purchase AB-155C you get every thing you'd expect to have gotten in this model. Threaded connections, beefy 3 way valve, and, finally, peace of mind. Weil-McLain could've made a decent unit. The evidence is in the bigger model. They simply decided not to.

I put this boiler in 3 years for a radiant heating system. The boiler fired right up everything worked fine. Fast forward 3 years and the unit is leaking in several places the CH return pipe had a slight leak that rotted the pipe out and the clip holding the temp sensor. The DHW R plate connector is leaking out of the bottom. The flow meter is leaking out of the top. Need to replace that and the flow meter pipe needs to be replaced. All total about $500 in part and 4 hours labor. I usually install Navien but none were avaible for this job due to COVID so I took a chance on a good name in boilers and got stuck with a piece of junk.

I have installed 4 of these boilers in the last three years. They all work great and are an inexpensive way to have heat and domestic hot water from one single unit

Easy to install

Easy installation, good heat, and unlimited domestic hot water on demand.

Our company installed this unit after installing other brands for years, and I must say we are pleased. the homeowner is grateful as well. Highly recommend professional installation as the installation manual is very vague. The only issue we ran into with this unit was with the outdoor temperature sensor. The boiler did not recognize that it was plugged in for several hours causing a slight delay, but was resolved by tech support. Otherwise very happy with the unit