Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
Weil-McLain AquaBalance AB-80H and Weil-McLain AquaBalance AB-120C are two combination (combi) boilers from the Weil-McLain AquaBalance line. The Weil-McLain AquaBalance AB-80H is rated 80 MBH input, 75 MBH output and 95% AFUE, and the Weil-McLain AquaBalance AB-120C is rated 120 MBH input, 112 MBH output and 95% AFUE. Weil-McLain AquaBalance AB-120C lists 40 MBH more input than Weil-McLain AquaBalance AB-80H (120 MBH against 80 MBH). Both list the same published AFUE of 95%. Weil-McLain AquaBalance AB-120C lists 16 lb more shipping weight than Weil-McLain AquaBalance AB-80H (80 lb against 64 lb).
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Weil-McLain AquaBalance AB-80H | Weil-McLain AquaBalance AB-120C |
|---|---|---|
| Input, maximum | 80 MBH | 120 MBH |
| DOE heating capacity | 75 MBH | 112 MBH |
| Efficiency (AFUE) | 95 % | 95 % |
| Turndown | 10:1 | 10:1 |
| Domestic hot water | Heating-only boiler; domestic hot water via an indirect tank | Integrated combi: built-in DHW flat plate heat exchanger with a 3-way valve and an internal 3-speed circulator |
| Weight | 64 lb | 80 lb |
| Venting | 2" or 3" PVC, CPVC, polypropylene or stainless steel (Category IV) | 2" or 3" PVC, CPVC, polypropylene or stainless steel (Category IV) |
| Heating water connections | 3/4" NPT | 3/4" NPT |
| Gas connection | 1/2" NPT | 1/2" NPT |
| Fuel | Natural gas or propane | Natural gas or propane |
| Net AHRI water rating | 65 MBH | 97 MBH |
Published ratings: the Weil-McLain AquaBalance AB-80H is rated 80 MBH input, 75 MBH output and 95% AFUE; the Weil-McLain AquaBalance AB-120C is rated 120 MBH input, 112 MBH output and 95% AFUE. Weil-McLain AquaBalance AB-120C lists 40 MBH more input than Weil-McLain AquaBalance AB-80H (120 MBH against 80 MBH). Both list the same published AFUE of 95%.
Weil-McLain AquaBalance AB-120C lists 16 lb more shipping weight than Weil-McLain AquaBalance AB-80H (80 lb against 64 lb). The domestic-hot-water arrangement differs: the Weil-McLain AquaBalance AB-80H lists Heating-only boiler; domestic hot water via an indirect tank, while the Weil-McLain AquaBalance AB-120C lists Integrated combi: built-in DHW flat plate heat exchanger with a 3-way valve and an internal 3-speed circulator.
Both records print the same AFUE (95%), turndown (10:1), venting (2" or 3" PVC, CPVC, polypropylene or stainless steel (Category IV)) and water connections (3/4" NPT), per the cited sources.
Weil-McLain
The AB-80H is the heat-only entry of the discontinued-in-Canada AquaBalance Series 2 line: 80 MBH CSA input, 75 MBH DOE heating capacity and a 65 MBH net AHRI rating at 95% AFUE in a 64 lb stainless steel wall-mount unit.
Weil-McLain
The AB-120C is the mid-size AquaBalance Series 2 combi, discontinued in Canada: 120 MBH CSA input, 112 MBH DOE heating capacity and an integrated DHW module at 95% AFUE, in an 80 lb wall-mounted stainless steel unit.
The Weil-McLain AquaBalance AB-120C lists 120 MBH, against 80 MBH on the Weil-McLain AquaBalance AB-80H, per the cited documentation.
Both list the same AFUE of 95%.
It ships at 80 lb against 64 lb for the Weil-McLain AquaBalance AB-80H, per the cited sources.
A consultation includes a heat-loss review so the size is right the first time.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.