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.
- 4 built-in heating zones, 7 reset curves
- Smart-Circ recirculation (combi models)
- On-board controller + outdoor reset sensor
- 96% AFUE, natural gas or propane
How Milani installs and services it
Milani sizes a tankless unit to your household — fixture count, simultaneous demand and the coldest incoming water temperature of the year — so it never runs out of hot water on a winter morning. We handle the gas line (tankless units draw more gas than a tank while they run), the venting, the condensate drain on condensing models, and the water and electrical connections, then set the temperature and register the warranty. Annual descaling keeps efficiency and flow where they should be, and we schedule it with you.
At a glance
- Combi (heat + hot water) or Solo (heat only) versions
- 96% AFUE condensing efficiency
- 4 built-in heating zones, 7 heating reset curves
- Smart-Circ Intelligent Recirculation on combi models
- On-board controller with outdoor reset sensor
- Natural gas or propane
Warranty
Rinnai residential boilers carry a limited warranty on the heat exchanger and on parts, with the term depending on the application and on the unit being registered. Milani registers the boiler at installation and keeps the documentation.
Talk to Milani about the I-Series Plus
We size the unit, handle the gas, venting and water connections, set the temperature and register the warranty — and check which rebates apply to your address.
This page is Milani's own summary of publicly documented Rinnai model designations and technology, provided for homeowner reference.
Milani is an independent installing dealer for Rinnai. Rinnai®, SENSEI®, Smart-Circ™, Circ-Logic™, Smart Sense™, Versa Vent™, Quick Flush™, Smart Connect™ and Rinnai Central™ are trademarks of Rinnai Corporation and its affiliates. Efficiency, capacity and warranty terms vary by configuration — Milani confirms the details for your home. This page is not an official Rinnai publication.