Condensing combi boiler · Heat + hot water
I-Series Plus
The Rinnai I-Series Plus is a wall-hung condensing boiler. On the combi models it does two jobs from one cabinet — space heating for a hydronic system and on-demand domestic hot water — which makes it the natural fit for a home that has radiators or in-floor heat and wants to drop its water tank at the same time. It reaches 96% AFUE and runs on natural gas or propane.
Heat and hot water from one unit
Combi models deliver space heating and domestic hot water at the same time, without one job interrupting the other, so a single wall-hung unit replaces both a boiler and a water heater. Solo models heat only and pair with an indirect tank where a large simultaneous hot-water draw is expected.
Comfort controls built in
The I-Series Plus has four heating zones and seven heating reset curves built in, so a multi-zone hydronic system can often be set up without an external zoning panel and the water temperature can be tuned to the emitters in each part of the house. Combi models add Smart-Circ Intelligent Recirculation for fast hot water at the taps.