Rinnai Rl75in Review In 2023

Are you looking for an indoor water heater for a small to mid-sized family?  You may opt for Rinnai rl75in, an excellent tankless water heater from a trusted brand. Analyzing Rinnai rl75in review, it’s found that it is treated as a top performer.

Due to its outstanding service, it has become a top-selling model of Rennai. Being a part of Rinnai’s “RL” line Rinnai RL75in is “high-efficiency plus” (HE+)’.People love it for its ability to recirculate heated water and its non-condensing features.

Suitcase-sized Rinnai rl75in has attained Uniform Energy Factor- UEFof 0.80 to 0.81. So, for indoor use, it is the best option.

Rinnai RL75iN Natural Gas Tankless Hot Water Heater

Rinnai RL75iN Natural Gas Tankless Hot Water Heater


Rinnai RL75iN review shows that installation of it is a bit of a difficult task. There is an instruction manual included in the pack to install it.

But the installation process must be done by a licensed professional. DIYers are not encouraged to do the task. Expert knowledge is required to perform the complicated task of plumbing, electrical, gas, and ventilation.

In case of any mistake related to installation, you will lose the warranty coverage.  Not only that, the safety of your family will be at risk.

Besides, you can’t expect efficient operation from a wrongly installed tankless heater and a long life expectancy of 20 years. Don’t go for saving just a few dollars In exchange for huge costs in the end.

Most of the Rinnai RL75iN review has highlighted its performance. The temperature of incoming water is 57° and, and the unit’s water delivery capacity is 4.7 GPM to 7.5 GPM. It has the ability to provide service to 3 showers. It is the best for 2 or 3-bedroom households.

Key Features of Rinnai RL75in 

The features of the Rinnai RL75in are very lucrative to draw consumers’ attention. It’s ultra-low NOx SCAQMD approved. Its key features are as follows:

  • Fuel: Natural Gas
  • Weight: 45.6 lbs
  • UEF: 0.81, a decent efficiency rate for a gas tankless water heater.
  • Energy Star: No
  • Dimensions: 26.9″H x 14.04″W x 9.27″D
  • Having a silver finish and a sculpted cover
  • Maximum Flow Rate: 7.5 GPM
  • Maximum BTU 180,000 
  • Min. BtuH Input: 10,300
  • Location: Indoor
  • Follows South Coast Air Quality Management District 14 ng/J or 20 ppm NOx emission levels
  • Maximum hot water flow rate: 7.5 GPM
  • Energy Factor: .82 for both Natural Gas and Best PropaneTankless Water Heater
  • Supports two to four fixtures at once
  • Temperature lock function
  • Certification: Installation in Manufactured (Mobile) Homes
  • Circ-Logic meaning a recirculating system – allows you to program the heater as per your requirement.
  • Cost ranging from $1,100 to $1,300
  • Last for 20+ years
  • Recirculation pump saves 100’s of gallons of water each year
  • A built-in “scale detection” feature
  • Non-condensing
  • Warranty: up to 12 years for heat exchanger, 5 years for parts and components, and 1 year of labor
  • Energy use: low
  • Less electricity consuming
  • Provides seamless supply of hot water
  • High installation charge
  • Installation being time-consuming



The RL75in follows non-condensing technology and you need to have special venting so that you can control the corrosive exhaust. Usually, a non-condensing unit will not cost you much while you purchase, but its installation cost is higher than the cost of a tankless water heater itself.

It will be advantageous for you if you are replacing another non-condensing tank. Because, you can use the same venting, and it will make your installation cost-effective.

User Manual

The user manual includes guidelines about the installation, operation, and maintenance of the water heater. To enjoy the best service from it and ensure its operation and safety, follow the instructions and maintain the safety precautions.

Install the water heater with the help of a licensed professional following the instructions on pages 4-30.

Go through the entire manual to operate the water heater and do regular maintenance.

You may use a durable copper heat exchanger to optimize heat transfer and get an Energy Factor rating of up to 0.82. It will increase its 18 percent efficiency than an ENERGY STAR-qualified storage tank.

The cir-Logic technology of Rinnai’s Luxury models offers an endless hot water supply. You may opt to add an external pump and dedicated recirculation line which enable hot water to move quickly to showers and faucets.

To make it less time and energy-consuming, a 24-hour digital controller can be programmed. It will ensure the availability of hot water to meet the high demand of rush hour in the early morning.

Troubleshooting With Error Codes

You are advised to troubleshoot following the error codes. TheError codes of Rinnai RL75in are :

  • EC LC0 – LC9 – scale buildup
  • EC 02 – indicates Failure of Burner Operation During Freeze Protection Mode
  • EC 03 – signifies Interrupted Power Supply During Bath Fill
  • EC 05 – refers to Bypass Servo; Turn the power on /off, it will be ok. If not change the bypass valve.
  • EC10 – indicates Blockage in Air Supply or Exhaust. You are to check the total venting system to find out blockage if there is any.
  • EC 11 – No sign of Ignition; You may check the gas valve at the gas meter and the tankless unit, the igniter’s function
  • EC 12 – is of two types – flame failure (gas) and immediate (electrical). Looking through the view window if you notice any flame during/ after the ignition cycle, it indicates flame failure (gas) error code 12. But if no flame is seen it is an immediate (electrical) error code 12. Sometimes it becomes difficult To determine whether it is due to gas or electrical. you are to turn the fire unit on, and turning off the gas unit. if error code 11 is shown it is a gas problem. If error code 12 is displayed it is nothing but an electrical short.
  • EC 14 -means Overheat or Thermal Fuse; It’s a serious issue either for the bi-metal safety switch or the thermal fuses. Try to notice any discoloration on the surface of the heat exchanger where the combustion box meets the copper section.
  • EC 16 – is for High-Temperature Warning; If the room temperature is above 104’F, the tankless become shut down. You need to clean obstructions (if any) on the air filter, vent terminates, or tankless surroundings.
  • EC 19 -shows Electrical Grounding meaning the existence of an electrical short in anywhere of your components.
  • EC 25 – indicates Blocked Condensate Trap. Look for blockage in the condensate drain line, condensate tank, and trap. You may search if there are any broken, loose, or damaged connections between the PC board and the sensor. if the tank draining is ok the sensor may need to be replaced.
  • EC 31 – is a Burner Thermocouple or gas system problem.
  • EC 32 – and 33 – water temp. Sensor
  • EC 34 – combustion air temp. sensor
  • EC 41 – temperature thermistor
  • EC 52 – solenoid valve problems
  • EC 57 – burner problem
  • EC 61 – fan problems
  • EC 65 – water flow problem
  • EC 70 – issues with the PC board
  • EC 72 – flame sensor
  • EC 79 – water leak
  • EC FF – maintenance performed

Before trying DIY you must remember that you may lose the warranty coverage if any damage happens. In every case, the suggestion is to look for a technician’s support.


  • Which places are preferable for using Rinnai rl75in?

You may choose it for indoor use but there is an outdoor model too.

  • Does a tankless water heater meet your needs?

Yes. A tankless water heater provides you with as much hot water as you need. And it does so without delay.

  • What is the average lifespan of Rinnai rl75in?

Depending on the proper maintenance, it may last up to 20+ years. If any leakage is found at the base of the heater or any other problem is noticed you have to replace the water heater.

  • How can you reset your Rinnai rl75in a tankless water heater?

To reset your Rinnai rl75in the tankless water heater, press and hold the connect button on your module, until you notice the LED blinking White.

  • What’s the way of resetting my Rinnai error code?

To reset LC codes, flush the water heater. You are to push the two switches A and B, located on the PC Board simultaneously for five seconds. Thus, you can normalize the operation and the LC# count returns to 0.

  • Why does my tankless water heater go cold?

If the water filter becomes dirty on cold water inlet, it may cause sudden temperature fluctuations at the time producing hot and cold water intermittently. And you may get cold water instead of hot water.

Final Word 

The Rinnai rl75in review establishes the fact that this tankless water heater is not frustrating in any way. It is identified as the top performer. When you intend to have a shower early in the morning, you will get the hot water ready to circulate through your home’s plumbing.

Just turn on the shower and enjoy your bathing with a seamless supply of hot water. Most interestingly, You have an option of controlling your water heater remaining at a distance from your smartphone.

Because they are Wi-Fi enabled and you can easily add the Control-R module and download the App to avail yourself of the opportunity. Hope this “Rinnai rl75in Review” post helps you.

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