Rinnai Water Heaters - Recent Questions, Troubleshooting & Support

Ideas in this link, but gas heaters need professional repair by a gas registered technician. https://www.google.com/search?q=Rinnai+Water+Heater.+It+is+not+heating ..

I could not find r85 model on rinnai website. There is a troubleshooting guide on rinnai website. 100000652-Troubleshooting TWH Diagnostic Codes.pdf (rinnai.us) It may help to find a solution.

check this out..... https://www.youtube.com/watch?v=eMeq-fRH-wE

No, there isn't an Error 09, but there is a E19. https://www.tanklesshotwaterguide.ca/about/rinnai-tankless-error-codes/ https://www.google.com/search?q=Rinnai+E110CN+error+E09 ...

Tankless promotion is certainly slick and inviting... -Tankless gas save about $100 per year vrs pre-april-2015 gas water heater for 'average family of 4.' -New energy standards will reduce the expected savings to $70/ per year. -Tankless electric cost about $100 more per year to operate than ordinary electric water heater for 'average family of 4' -Do-it-yourself repairs are generally not possible with tankless. -Tankless gas require larger vent and larger gas line, and a condensate drain. -Whole-house Tankless electric will probably require a new electric service panel -Tankless require yearly deliming/ descaling of heat exchanger... and heat exchanger will lose efficiency over time because of scale... even if unit is delimed each year. -Electronic controls are vulnerable to surge -Only the alloy heat exchanger has long-term warranty, but otherwise the warranty is same as typical tank heater -Tankless cannot be exposed to more than 11 grains hard water or parts can fail within 2-3 years -Tankless might not be able to keep up with higher temperature setting needed to fill very large tub (or any bathtub) if incoming water is too cold due to winter conditions. Etc. Example Rheem tankless resource: http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html http://waterheatertimer.org/pro-n-con-for-tankless-water-heater.html Example installation for tankless electric http://waterheatertimer.org/How-to-wire-Tankless-electric-water-heater.html Gene Water Heater Timers Save Money If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Question edited for clarity. Question moved from Kitchen Ranges. Sounds like the temperature sensor is failing. https://www.google.com/search?q=rinnai+e110cn+set+back+temperature ..

12 - Flame Failure or Poor Ground

1. Immediate code 12 is usually a defective gas valve, power supply problem, or defective fan motor wiring harness.

2. If code 12 occurs after a few seconds it indicates that proper operation was established, but then stopped unexpectedly.

3. Verify that fuel is being supplied to the unit.

4. Check for proper electrical ground. Unit must use a grounded power supply.

5. Check for flue blockage on inlet or exhaust.

http://www.foreverhotwater.com/service-codes.php

trouble shooting section will help https://sahotwater.com.au/specifications/Rinnai/Service%20manual/smV1616W_V2018W_V2020W.pdf

possible bad power transformer or unit is overheating

if unit is igniting check to see if gas valve opens if yes check burner tubes for cob webs

If it is hot in the kitchen, then once the water has reached the shower it should be hot. The leads me to believe that the issue is with your shower mixer unit. Nearly all are thermostatically controlled. Or, if the heater is downstairs and the bathroom is upstairs, you don't have enough hot water pressure. You need a good plumber with a pressure tester (called a manometer).

A Rinnai fault code 10 is an indication of either an issue with the air intake or a blocked flue. Your first step should always be turning your system on and off to see if the Rinnaifault code 10 has disappeared. If it hasn't, check the vent system for blockages and other issues that could prevent airflow.

One thing they don't tell you about tankless heaters is that when they turn on, they may cause the lights in the house to flicker. Make sure that you have a good breaker panel (one that is relatively new with plenty of capacity) and run a circuit specifically for the tankless heater.

Push breaker(s) fully off and then back on. ... then open the tankless and carefully test across the terminals where wires connect to heater... Tape tester leads to wood sticks to keep hands away from power Following link has wiring for tankless electric http://waterheatertimer.org/How-to-wire-Tankless-electric-water-heater-new.html

I wonder if you have this problem below caused by a drop in water pressure from someone flushing a toilet or a washing machine. I would call the company to remedy this issue.

17. What is a cold water sandwich effect? The term “cold water sandwich effect” is a term that is used to describe the introduction of cold water into the hot water supply line during frequent on/off operation of an instantaneous water heater. The cold water sandwich effect, when present, appears as a momentary drop in hot water temperature as it is discharged from a hot water supply outlet (i.e. shower, tub, or faucet). This phenomenon is present in the operation of all instantaneous, tankless style, water heaters, but is minimized with the high tech design of Rinnai water heaters.
The technology built into the Rinnai water heaters is designed to minimize the cold water sandwich effect. Rinnai water heaters are microprocessor controlled and when water flow through them ceases, they remain in a “ready to fire state” for approximately 1 minute. If water flow through a Rinnai water heater begins within the first minute following water flow stoppage, the water heater will fire back up within 1 to 2 seconds. This minimizes the cold water sandwich effect that would otherwise be experienced with a low tech tankless water heater. It should be noted that the cold water sandwich effect cannot be removed completely from tankless style water heaters. The safety standards developed to insure the safe operation of water heaters require a delay in the ignition sequence of all gas water heaters.
While the cold water sandwich effect cannot be completely eliminated from standard plumbing systems, it can be eliminated from plumbing systems that have a supply and return hot water circulating system. Rinnai has developed 2 methods to eliminate the cold water sandwich effect in residential hot water circulating systems.
The first (and preferred) method to remove the cold water sandwich from circulating systems utilizes a small electric tank water heater (powered up) that is used with a dual purpose. The small water heater acts as a mixing tank to eliminate the cold water sandwich effect from the Rinnai water heater and it uses its electric heating element to offset the heat losses from the hot water circulating system.
The second method to remove the cold water sandwich from circulating systems utilizes a small 2 to 6 gallon storage tank installed on the hot water outlet of the Rinnai water heater. This tank acts as a mixing tank to blend the cold water sandwich with hot water and eliminating its effect at fixtures.

Unplug it and plug it back in it should work

The dial on the front panel of the heater. https://rinnaithailand.com/wp-content/uploads/2015/07/gas-water-heater_REU-55RT_and_REU-55RTL20001.pdf

Code 12 is a flame failure. First step in diagnosing the root of the issue is to check for any separation, obstruction, or failure in the vent system. Second step is to use the isolator kit under the heater to flush the heat exchanger with vinegar or rectorseal calci-free. These two things are a great starting point to working on any tankless water heater. Flame failure can be as simple as the heat exchanger being clogged not allowing the sensors to work properly or the exhaust being mixed with the air intake. If the problem persists I would suggest having a Rinnai Certified Tech look at the heater.

Order a controller