Rinnai RU98 Water Heaters Review

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Rinnai RU98 tankless and condensing water heaters for ultra efficient water heating. How RU98 is utilizing the latest advanced technology to maximize the efficiency and comfort.

Models review

Rinnai RU98 tankless water heaters are designed as the indoor RU98i and outdoor RU98e units, both using two exchangers and the condensing technology, which results in the extremely high energy factor of 0.95, either using natural gas or propane. The heaters belong to the "Ultra" series, a models with the largest capacity and recommended for homes with up to four bathrooms.

With the purchase of any Rinnai Ru98 model, you will get the warranty of 10 years on the heat exchanger or 12 if the isolation valve kit is installed.

Rinnai Ru98i

Rinnai Ru98i

Rinnai RU98i model can be installed indoor only and thanks to its direct vent system and sealed combustion chamber it gets enough air for combustion while it safely removes the exhaust gases outside. The Rinnai RU8i models are designed to use either concentric (pipe within the pipe) system or two pipe system that runs horizontally through the outside wall or vertically through the roof. Since the exhaust gases are released with the lower temperature than the typical non-condensing model, cheaper vent pipes are used (PVC or CPVC).

Every indoor unit has the digital temperature controller built in.

Rinnai RU98e

Rinnai RU98e

Rinnai RU98e doesn't require pipes for the air intake or exhaust as they are already installed outside. The digital temperature controller is not built-in but it is provided with the unit.

Where to buy

You can buy Rinnai RU98, either outdoor or indoor type, also natural gas or propane gas unit for approximately $1300 to $1400. All units have great customer reviews which is between 4 and 5 stars.

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Features review

  • Direct electronic ignition eliminates the need for the pilot light.

  • Ultra Low NOx burner complies with the 20 ppm NOx emission levels.

  • Digital temperature controller MC-91-2US shows the hot water temperature and if the problem appears, the error codes.
  • Enhanced scale detection.

  • Built-in Rinnai Circ-Logic recirculation program, which recirculate water in two modes: Economy and Comfort, in residential applications.
  • Hot water temperature lock, which prevents accidental or intentional temperature changes.

  • Water flow sensor, electronic water control device and electronic by-pass control.

  • Safety features for the flame and boiling protection, combustion fan check, remaining flame OHS, automatic frost protection (protects the unit when the outside temperature is up to -22 F)...

  • Diagnostic systems helps in service.

  • PC board.

Specifications - Technical Data

RU98i RU98e
Gas Input
15,200 – 199,000 15,200 – 199,000
Water Flow
0.26-9.8 0.26-9.8
Energy Factor
0.95 0.95
Activation rate
0.4 0.4
Temp. settings
98-140 98-140
Electric consumption
64 63
Max. vent length
41' - one pipe system
42' - two pipe system
Altitude height
10200 10200
18.3x26x10 18.3x26x10
61.7 61.7

(Photo credit to Rinnai)