Product Overview
The Rinnai RL75 is part of the HE+ Series, a non-condensing line of high efficiency tankless hot water heaters. The RL75 is for residential use but can also be used in commercial installations. The RL75 is available in either Natural Gas or Liquid Propane and must be purchased for indoor or outdoor use*. Indoor versus outdoor installation is not interchangeable and must be decided at time of purchase. Indoor installation of the RL75 utilizes concentric venting. With concentric venting, one pipe allows for fresh outside air in, while the other allows for exhaust to go out. Outdoor installation does not require venting. The RL75e is for outdoor installation does not require venting. Because of extreme temperatures and exposed water lines, outdoor / exterior installation it is not recommended in locations from Virginia and north. Also keep this in mind in mountainous regions of the country where extreme temperatures may also exist.
It features 180,000 BTUs and hot water delivery with a flow rate that ranges from 0.26 - 7.5 GPM. The minimum GPMs is perfect for low demand uses such as shaving, where warm water is needed but not at a high rate! It is the ideal tankless solution for a home with 2 - 3 bathrooms. The RL75 is optimal for simultaneous use of 2 - 4 fixtures at one time. So 2 people can shower and get ready to go out, while someone else is washing the dishes, and not fear running out of hot water. Simultaneous fixture use is directly linked to the ground water temperature. Please refer to the chart in the photos above. The MC-91-2US controller is included with the water heater. The standard temperature range is 98° with a maximum of 120°F. The unit offers maximum settings at 140°F (160°F commercial with MCC-91-2 controller) with field adjusted switch settings.
In a non-condensing tankless water heater, such as the RL75, once you turn on the tap, cold water goes into tankless heater and the flame is activated. Water is heated as it passes through the coils in the copper heat exchanger, exits the water heater, into your pipes and up to the fixture calling for the hot water. Depending on the amount of hot water called for, the flame adjusts accordingly to heat more or less water.

Benefits of a Tankless Hot Water Heater:
- Endless hot water - Heats water as it goes through the pipes, offering endless hot water for your home (or business)
- Hot water on demand - Once you turn the water on, hot water runs through your pipes and out the faucet! Virtually no time or water is wasted waiting for the water to heat up
- Highly Efficient - Gallon for gallon, you will spend less money heating your hot water. With a tankless system the water is heated on demand rather than sitting in a storage tank. A storage tank typically heats the water intermittently throughout the day and night not only when it is needed. This unit features an Energy Factor of 0.82 (the closer to 1.0 the better)
- Long lasting - Unlike a storage tank in which the water sits in the tank all the time creating sediment and rust, a tankless water heater will last longer
- EZ Connect - Allows for connection of two units together
The Rinnai HE+ Luxury line of tankless hot water heaters includes Circ-Logic capabilities. Recirculation allows for the water in the plumbing system to provide hot water more quickly once the tap is opened, using the cold water line for recirculation. The recirculation mode is for use in residential installations only. Additional accessories such as a thermal bypass valve are required unless there is a dedicated return line installed in your home. The RL75 offers WiFi Technology (Control-R WiFi Module sold separately) for remote monitoring, management. (Remote diagnostics and monitoring requires a monitoring dealer.) With WiFi monitoring, only Rinnai Service Providers can monitor the efficiency of your tankless water heater. Also included with the RL75 are isolation valves for easier maintenance and service.
With a tankless hot water heater, space is rarely an issue. A Rinnai RL75 tankless heater takes up about as much space as a carry-on suitcase - 23"h x 14"w x 9"d. They are designed to be installed on a wall with the following clearances:
Clearances | ||
From Combustibles | From Non-Combustibles | |
Top: | 12" | 2" |
Bottom / Ground: | 12" | 2" |
Front (Panel): | 24" | 24" |
Front (Exhaust): | 24" | 0" (minimum of 24" required for servicing) |
Sides: | 6" | 1/8" |
*Indoor and Outdoor Installation are specific to the model chosen. RL75eP and RL75eN are designed for outdoor/exterior installation and no venting is required while RL75iP and RL75iN are for indoor installation and do require venting. Both installation types are available in either Liquid Propane (P) or Natural Gas (N). Certified for installation in Manufactured (Mobile) Homes.
To find a local, Rinnai-trained Advanced Comfort Expert that installs Rinnai products in your area click here.
As an added bonus Rinnai has partnered with Folds of Honor. For every Rinnai tankless water heater or boiler that is sold, a contribution is made to Folds of Honor. This provides over 50 scholarships to trade schools for the spouses and children of America's fallen and disabled service members.
- Bay Area AQMD (Reg 9, Rule 6)
- Sacramento Metropolitan AQMD (Rule 411)
- San Joaquin Valley APCD (Rule 4902)
- Santa Barbara County APCD (Rule 352)
- South Coast AQMD (Rule 1146)
- Ventura County AQMD (Rule 74-11)
- Yolo-Solano AQMD (Rule 2.37)
Tech Specs
WARNING!
Product Warranty
It is recommended that you use a Rinnai Authorized Installer when installing your hot water heater. Your hot water heater includes a
Residential Warranty:
- Limited 12 Year Warranty on Heat Exchanger
- 5 Year Warranty on Parts
- 1 Year Labor Warranty (extended to 5 years if registered within 30 days)
Commercial Warranty:
- Limited 5 Year Warranty on Heat Exchanger
- 5 Year Warranty on Parts
- 1 Year Labor Warranty (extended to 2 years if registered within 30 days)
Please note Rinnai is adjusting the language in its warranty terms and conditions currently noted in the User Installation manuals. The revised statement will read as follows: "This Limited Warranty applies only to products that are installed in the United States and Canada. Improper installation may void this Limited Warranty. It is recommended that a trained and qualified professional who has attended a Rinnai installation training class complete your installation."
All warranties will be honored as written above.