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Internet # 311397846

Model # i120CN

Store SKU # 1004745532

I Series Natural Gas Combi Boiler with 120,000 BTU Input

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  • Facilitates simultaneous delivery of hot water and home heating
  • Features Outdoor Reset control for optimized heating performance
  • Built-in orifice ensures quick gas conversion for faster results
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Product Details

The I- Series i120CN model features Rinnais exclusive self-cleaning stainless-steel heat exchanger coupled with a secondary flat plate heat exchanger. Our combi models can deliver whole house heating and simultaneous domestic hot water. The i120CN provides an input rating of 120K BTU. Fueled with either Natural Gas or Propane this Rinnai condensing gas boiler has obtained 1 of the highest AFUEs (Annual Fuel Utilization Efficiency) in the industry. Plus, the compact wall-mounted design saves space over traditional boilers.
  • i120CN combi condensing gas boiler model offers high volume domestic hot water delivery providing endless hot water for whole home along with the comfort of whole home heating
  • Combi models offer outdoor reset to optimize your home heating performance and features an integrated modulating pump, with an outdoor reset sensor (in the box)
  • Excellent operational performance with 95% AFUE efficiency and ENERGY STAR most efficient certified
  • Convenient control options with the ability to connect 2 zone pumps to the PCB
  • Easy parameter settings and a user-friendly interface
  • Versatile venting options including 2 in. PVC up to 65 ft.
  • Quick natural gas (NG) to propane (LP) gas conversions (kit included)
  • Stainless steel heat exchangers (primary, secondary and DHW plate) throughout boiler for unmatched performance and durability
  • Delivers proven reliability with residential warranty: 12-year heat exchanger, 2-year parts, 1-year labor
  • Return Policy
  • California residents


Dimensions: H 26.4 in, W 18.5 in, D 10.9 in


Product Depth (in.)10.9 inProduct Height (in.)26.4 in
Product Width (in.)18.5 in


Annual Fuel Utilization Efficiency (AFUE) (%)95Capacity (gallons)1
ColorSilverColor FamilyMetallics
Condensing/noncondensingCondensingEnergy Consumption (kWh/year)1384
Fuel GaugeNoFuel TypeNatural Gas
Heat rating (BTU/hour)120000 Btu/hHeating Product TypeBoiler
Heating Technology TypeRadiantIgnition TypeElectrical
Pack Size1Product Weight (lb.)76.1 lb

Warranty / Certifications

Certifications and ListingsASME Certified, CSA Certified, Energy StarManufacturer Warranty12-Year Heat Exchanger, 2 Year Parts, 1-Year Labor

Questions & Answers

Q:On the Rinnia i120 c comb boiler can you set the DHW from 120 degrees to 140 degrees ?
by|Nov 9, 2023
0 Answer
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Q:How many gallons a min can it do ?
by|Oct 2, 2023
0 Answer
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Q:Can this unit be used for domestic hot water only and add home heating coils at a later time
by|Aug 25, 2023
1 Answer
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A:  This boiler is suitable for combination water heating and central heating. Rinnai requires the use of hydraulic separation between the boiler and central heating system. Hydraulic separation and primary/secondary piping allow two or more circulators in a hydronic system to operate independently, without interfering with flow in connecting piping circuits. - Thank you, Rinnai Customer Care.

by|Nov 28, 2023
    Q:Can this replace a traditional oil burner?
    by|Jul 1, 2023
    1 Answer
    Answer This Question

    A:  Hello, Rinnai offers a live chat agent and a tool on our website to assist in selecting a product that best fits your needs please click on the following link https://www.rinnai.us/residential/solution-selector. Thank you, Rinnai Customer Care

    by|Jul 3, 2023
      Showing 1-4 of 35

      Customer Reviews

      3.5 out of 5
      • 3.5
        out of 15 reviews
      • 50% recommend this product
      Filter by:
      Showing 1-10 of 15 reviews
      I am using this unit to heat my whole house with hydrophonic radiant floor heating including my g...
      I am using this unit to heat my whole house with hydrophonic radiant floor heating including my garage and shop floors great efficiency low propane usage quite and smart with the outdoor tempature gauge the system knows to adjust flame and keeps it running at optimal savings
      • DIY
      • Verified Purchase
      • Recommended
      2 found this review helpful
      Replaced an old boiler in a closed single loop system using externally controlled zone valves. Everything from the original setup connected right up. Old boiler was over 320 lbs., short cycled, and sounded like a freight train. Rinnai is lightweight, doesn’t short cycle, and is barely audible.
        This product is junk
        I have this boiler in my home and it is awful, the unit fails all the time with E400 or E430 error messages. Now Rinnai says they won't back the product and the failing sensor is extremely hard to find...probably since it fails so often! I've had it repaired 3 times in under 2 years and I'm considering just replacing the entire unit now. I certainly won't replace it with a Rinnai!!!
        Response from Rinnai Product ExpertJun 16, 2023
        Hello Luke, we are apologetic to hear of the current concerns you have addressed here. Rinnai has some questions and wants to help you further. Can you please email us at feedback@rinnai.us. - Thank you, Customer Care RinnaiAmerica
          when they are working they are good but ...
          works well when actually working but unit is less than 3 yrs old and already $2500 in repairs and parts can take 4-6 weeks so you are without heat and hot water that whole time . Also hardly anyone in this area knows how fix them so it is basically an experiment in trial and error at consumers cost . I would not recommend buying this brand
          Response from Rinnai Product ExpertApr 7, 2023
          Hello Keith, Sorry for the issues you have addressed here. Rinnai has some questions and want to help you further. Can you please email us at feedback@rinnai.us. - Brittany, Customer Care RinnaiAmerica
            Excellent product
            Excellent water heater, works great, very satisfied.
            • Verified Purchase
            • Recommended
            Good little unit
            I am in a 1400 sq foot town house. This unit heats and gives us domestic hot water. Haven't had it long but as of right now its a nice little unit and does what it is supposed to. Some other reviews online I have seen say it takes a while to get hot water to the tap. This is true but once it gets to the tap it is on as long as you need it. Would recommend.
              • Recommended
              3 found this review helpful
              disaster unit
              Swipped an old unit with this, thinking it would be a fair an easy task but when main heat water supply was connected, water started coming from inside unit. The unit is not even powered yet (brand new) and no gas has been connected also, (cant imagine what type of problem that would also bring) i called RENNAI customer service and first thing they asked if i had a license, I told them no but i have a video of the water comming from inside this unit, they wont accept it unless a license person contacts them directly with proofs. Paid $3500 for this.
              Response from Rinnai Product ExpertDec 13, 2022
              Sorry for the issues you had hear, we have some questions and want to help. Can you please email us at feedback@rinnai.us. ---Tashay RinnaiAmerica
                • Recommended
                2 found this review helpful
                Don’t purchase this type of product from HD. Their agreement with manufacturers requires HD to manage warranty issues and they have no idea how to do this. The manufacture is left in the position where they can’t support their own product. HD was selling Rheem combi s, not any more?
                Response from Rinnai Product ExpertOct 25, 2022
                I am sorry for any confusion. Our responsibility as a manufacturer is to honor warranty on the product. I am not sure what happened here. Can you please email us at feedback@rinnai.us? We have some questions and would like to make efforts to ensure we help where we can. --Tashay RinnaiAmerica
                  3 found this review helpful
                  Defective Unit
                  The unit had two steps for converting to propane. Switch out a gasket which was very easy and push a red button on the board to tell the unit it was burning propane. No matter how long I pushed the red button nothing happened. So the unit would immediately over heat when turned on. Rinnai support did absolutely nothing except ask if I had looked on their site. I did and there was nothing. HD made the return easy but what a giant pain. Now I have to wait a week for a new unit.
                    1 found this review helpful
                    Easy install, my HD didn't stock the combination vent kit...
                    Easy install, my HD didn't stock the combination vent kit so I had to source it elsewhere
                    • Verified Purchase
                    Showing 1-10 of 15 reviews

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