Rinnai Tankless flashing an error code?

    If you’re looking for help fixing your Rinnai tankless water heater or combination boiler, look no further than to the experts the manufacturer refers to Natural Choice Heating & Cooling as Rinnai PRO’s.  We have been installing tankless since 2005 and have well over 3,000 clients enjoying endless hot water!

    It is ‘always’ best practice to have a licensed Gas technician complete a thorough assessment, however it is good to know what you are looking at for the reason you have “no hot water”.

    If you have a tankless water heater, you’ve made a wise investment that will deliver endless hot water for 20+ years. Tankless water heaters need far less in the way of maintenance and servicing than traditional tank water heaters, but they still do need to be maintained, and when they have problems, it’s important to know what to do. We service all brands, but for this post we’re focusing on Rinnai tankless water heater troubleshooting because the self diagnostics tool provides codes that makes it easier to diagnose and address issues.

    We’re huge fans of Rinnai tankless systems! Your Rinnai tankless water heater is a smart water heater, meaning it is equipped with a self-diagnostic tool that continuously monitors if the unit is functioning properly. When something goes wrong, the unit displays an error code. Using this Rinnai tankless water heater error code guide, you can quickly determine what the problem is and if you need a plumber to service the unit or if you can fix it yourself.

Tankless Error Code Breakdown

Error Code 02: No burner operation during freeze protection mode.

Fix – Call a Licensed Gas Fitter/Company.  What has happened is the unit is frozen and “might” be damaged.

Error Code 03: Power interruption during bath fill

Turn off all hot water faucets/taps. Press On/Off button twice. Turn hot water back on and test. You may have to try this a couple times to reset the system.

Error Code 10: Exhaust or air supply blocked

There are several things you can do before calling a gas fitter. Try the following:

• Check venting material. Is it Rinnai-approved?  If not, replace venting material or have a gas technician replace it.
• Look for blockages in both the flue inlet or exhaust.
• Are the venting components properly connected? (do not try to disconnect/reconnect)
• Check the condensation collar. Is it loose or improperly installed?
• Are the dip switches set correctly? (not advisable to adjust if you do not feel confident as you can damage the unit)
• Is the fan rotating properly, or is something blocking it?  Do you hear the exhaust motor coming on?

If the error code still shows, call Us to set up a service diagnosis

Error Code 11: Ignition problems

Because this has to do with gas and gas lines, most people will need to call a licensed gas fitter (us) to handle this. However, these are steps the technician will take (and you could carefully review yourself):

• Is the gas on? Check at the water heater, gas meter or cylinder.
• Is the gas type and pressure correct? (this should only be checked by a licensed technician)
• Is the gas line, meter and/or regulator sized properly? (this should only be checked by a licensed technician)
• Is the air in the gas line? Have a gas technician bleed the air from the lines.
• Are the dip switches set? (not advisable to adjust if you do not feel confident as you can damage the unit)
• Is the appliance grounded? This is a copper braided copper wire must connect to your gas line, anywhere in the gas system
• Disconnect EZConnect™ or MSA controls to see if you can isolate the problem. (this should only be checked by a licensed technician)
• Does the igniter work? Is it operational or do you need to replace the igniter? Check the wiring harness and see if it’s the igniter or the harness. (this should only be checked by a licensed technician)
• Examine the gas solenoid valves. Any open or short circuits? (this should only be checked by a licensed technician)
• Remove the burner cover and examine the burners to see if they are one, properly sealed, and two, if the burner surface has condensation or debris on it. (this should only be checked by a licensed technician)

If you are not familiar with these parts and with both wiring and gas, you should hire a Us to deal with a Rinnai error code 11.

Error Code 12: Flame failure

Because this has to do with gas and gas lines, most people will need to call a licensed HVAC to handle this. However, this error code should only be checked by a licensed technician.

• Check power supply. Any loose connections? 
• What is the voltage? Any voltage drops? 
• Is the flame rod wire connected? Any problems with carbon build up on the flame rod?
• Check for DC shorts at components.

Error Code 14: Thermal fuse

Something is wrong with the thermal fuse. This Error should be reviewed by a trained licensed technician 

• Check for air flow restrictions.
• Is water flow in the circulating system low? This can cause problems related to short-cycling.
• Check dip switches.
• Anything gunking up the combustion chamber? What about the exhaust pipe? Obstructions can cause problems with thermal fuse function.
• How does the heat exchanger look? Any cracking or separations? Hot spots? Hot spots indicate scale build up.
• Flush the heat exchanger following the instructions on the owner’s manual.
• Check the resistance of the safety circuit.

Error Code 16: Over temperature warming

This problem usually is caused by a restriction of airflow. Check for clogs or obstructions in the following: Some of these would be best checked by a trained technician 

• Combustion chamber
• Exhaust piping
• Heat exchanger

You will also want to check for restrictions in air flow around unit and vent terminal and for low water flow in a circulating system causing short-cycling. Once you clear the obstructions and improve airflow and water flow, the problem should resolve itself.

Error Code 32: Outgoing Water Temperature Sensor Fault

This one is simple for a trained technician: carefully examine the sensor. Look for damage and scale build up. You probably have to replace the sensor if cleaning it doesn’t help.

Error Code 33: Heat Exchanger Outgoing Temperature Sensor Fault

Similar to above. Carefully examine the sensor. Look for damage and scale build up and make sure the fan blade is tight on motor shaft and is undamaged. You probably have to replace the sensor if cleaning it doesn’t help.

Error Code 34: Combustion Air Temperature Sensor Fault

Same as above. Carefully examine the sensor and wiring. Look for damage and scale build up. You probably have to replace the sensor if cleaning it doesn’t help.

Error Code 52: Modulating Solenoid Valve Signal Abnormal

You probably need to replace the solenoid valve. First:

• Check modulating gas solenoid valve wiring harness for loose or damaged terminals.
• Measure resistance of valve coil.

A trained technician may be able to resolve the problem by tightening loose terminals or replacing the gas valve.

Error Code 61: Combustion Fan Failure

Examine the combustion fan to see: (most suggestions are best completed by a trained license technician)

• Do you hear the fan motor coming on?
• Can the fan turn freely?
• Any problems with the wiring harness? Maybe it has been damaged or has loose connections?
• Is there a problem with the motor winding resistance?

Error Code 65: Water Flow Control Fault

You definitely need to call a trained license technician for this one. The water flow control valve has failed to close during the bath fill function. Immediately turn off the water and discontinue the bath fill function.

Error Code 71: Solenoid Valve Circuit Fault

You probably need to replace the solenoid valve. (most suggestions are best completed by a trained license technician)

• Check wiring harness to all solenoids.
• Measure resistance of each solenoid valve coil.

Error Code 72: Flame Sensing Device Fault

All suggestions are best completed by a trained license technician

• Check to see if the flame rod is touching flame when the unit fires.
• Examine the wiring to flame rod for damage.
• Clean the flame rod with sandpaper.
• Examine inside the burner chamber for debris or gunk that might be blocking the flame at the flame rod.
• Replace flame rod.

Error Code 00 or “LC”: Scale build up in heat exchanger.

When was the last time your tankless was flushed/serviced?  You can complete this task yourself if you feel confident, or call us and it would be our pleasure to do it for you.

Note: A lot of customers ignore this code because it still allows the tankless water heater to continue running. You will see the display alternates between the LC code and the temperature setting. Make sure you get the heat exchanger serviced and don’t ignore this code just because it allows you to still run the unit or you may have more serious problems down the line.

Need a Gas fitter for Tankless Water Heater Help?

This post is about Rinnai tankless water heater troubleshooting because that’s the brand we install the most often, but we have deep experience with all brands of tankless (on demand) water heaters. Give us a call at 905.424.2090 to service your tankless water heater. We look forward to working with you!

Tasks to Leave to a Tankless Repair Expert

When troubleshooting your tankless doesn’t solve your hot water issues, never hesitate to contact a trained HVAC contractor. Any tankless, regardless of its age, may pose combustion- or gas-related safety hazards, so it’s always a good idea to have an expert examine the unit and suggest the best course of action.