Rinnai Tankless Water Heater Error Codes: Complete Diagnostic List
30 diagnostic codes documented · Official site ↗
🟡 Warning — Schedule Service
Stagnant Water Detection
The Rinnai 02 error code indicates that the water heater has detected stagnant water in the tank. This can happen when the water isn't being used or cycled for an extended period. While this isn't an immediate safety hazard, stagnant water can lead to bacterial growth and unpleasant odors. It's important to address this issue to maintain the water quality and prevent potential health risks.
Air Supply/Exhaust Blockage
The Rinnai 10 error code indicates that your water heater has sensed a restriction in the airflow to its combustion chamber or exhaust vent. This could be due to a blockage caused by lint, dust, or other debris. If left unchecked, this could lead to a buildup of carbon monoxide, a hazardous gas that can be deadly in high concentrations. It's important to address this issue promptly to ensure the safety of your home and family.
No Ignition
Error code 11 on your Rinnai water heater indicates a 'No Ignition' issue. This means the burner isn't firing up to heat your water. This could be due to a few reasons, but don't worry, it's usually a simple fix. Let's dive into the possible causes and what you can do to troubleshoot this at home.
Flame Failure
The Rinnai 12 error code indicates that your water heater's flame has gone out, preventing it from heating water. This could be due to a few reasons, but don't worry, it's usually an easy fix. The most common cause is a problem with the ignition system, but it could also be a gas supply issue or a faulty temperature sensor.
Thermal Fuse
Error code 14 on your Rinnai water heater indicates a problem with the thermal fuse, a safety device that cuts power to the heating elements when temperatures get too high. This is a common issue and usually user-fixable, but it's important to address it promptly to prevent further damage or system lockout.
Rinnai Code 15 - Hot Water Temperature Too High
Rinnai error code 15 indicates that the hot water temperature inside your tankless water heater has exceeded its safety limit. This triggers a safety shutdown to prevent scalding and potential damage to the unit. Several factors can cause this, but it usually boils down to a problem with the temperature sensors, the flow rate of water through the unit, or issues with the burner firing rate. When the water gets too hot, the unit locks out and displays this error code, preventing further operation until the issue is resolved. This is a safety feature, so it's important to address the underlying cause rather than just resetting the unit repeatedly. Ignoring this error could lead to scalding water or permanent damage to your Rinnai tankless water heater.
Over-Temperature
Error code 16 on your Rinnai water heater indicates that the temperature has exceeded the safe operating range. This could be due to a faulty temperature sensor, a problem with the heating element, or an issue with the water flow rate. It's important to address this issue promptly to prevent further damage to your water heater.
Rinnai Code 17 - Exhaust or Intake Blockage
Rinnai error code 17 indicates a problem with the venting system. Specifically, the unit's sensors have detected an obstruction in either the exhaust vent (where combustion gases leave the unit) or the intake vent (where fresh air enters for combustion). This is important because proper venting is needed for safe and efficient operation. If exhaust gases can't escape, they could potentially back up into your home. Also, the unit needs the correct air-to-fuel ratio to burn cleanly. When the control board detects a blockage, it shuts down the unit as a safety precaution. The unit will not operate until the blockage is cleared and the error code is reset. This protects you from potentially dangerous conditions and prevents damage to the unit.
Rinnai Code 18 - Exhaust Thermistor Fault
Rinnai error code 18 indicates a fault with the exhaust thermistor, which is a temperature-sensitive resistor that monitors the temperature of the exhaust gases leaving your tankless water heater. The unit's control board relies on accurate readings from this thermistor to ensure safe and efficient operation. If the thermistor is faulty, sending incorrect or no data, the unit will shut down to prevent potential overheating or other problems. This shutdown is a safety measure. The control board needs to know the exhaust temperature to properly modulate the burner and fan speed. A faulty thermistor can lead to the unit running too hot, potentially damaging components or creating unsafe exhaust conditions. It's important to address this issue promptly to restore hot water and ensure the continued safe operation of your Rinnai tankless water heater.
Electrical Grounding
Rinnai error code 19 indicates a problem with the electrical grounding of your water heater. This could be due to a faulty ground wire, a poor connection, or a problem with the grounding electrode. The system has detected a voltage reading that's outside of its normal range, causing it to shut down to prevent potential damage.
Condensate Overflow
Error code 25 on your Rinnai water heater means that the condensate neutralizer is overflowing. This could be due to a clogged drain line, a faulty neutralizer, or a problem with the water supply. The system has shut down to prevent further issues, and you'll need to troubleshoot and fix the problem before it can resume normal operation.
Condensate Neutralizer
Error code 29 on your Rinnai water heater means the condensate neutralizer, which helps maintain a safe pH level in the condensate, isn't functioning properly. This could be due to a clogged neutralizer or a faulty sensor. Although this isn't an immediate safety hazard, it's crucial to address this issue to prevent potential damage to your water heater and ensure its longevity.
Inlet Thermistor Failure
Rinnai's error code 31, Inlet Thermistor Failure, indicates a problem with the sensor that measures the temperature of the incoming water. This sensor helps regulate the water heater's operation and ensure safety. If it malfunctions, the water heater will shut down to prevent overheating or freezing, displaying error code 31 on the digital display.
Outlet Thermistor Failure
The Rinnai 32 error code signifies that the outlet thermistor, a temperature-sensing component, has failed. This part is responsible for monitoring the water temperature at the outlet. When it malfunctions, your water heater may not heat water correctly or at all, leading to cold showers or other inconveniences. In some cases, the heater may overheat, potentially causing water damage or other issues.
Heat Exchanger Thermistor
Error code 33 on your Rinnai water heater indicates a problem with the heat exchanger thermistor. This sensor monitors the temperature of the heat exchanger and helps regulate the water temperature. If it's not working properly, your water heater may not heat water or could shut down to prevent overheating. This is a yellow hazard level because it's safe to troubleshoot, but you should call a professional for repairs.
Combustion Air Thermistor
The Rinnai 34 error code indicates a problem with the combustion air thermistor, a safety component that monitors the temperature of the incoming air. When this sensor malfunctions, your water heater may shut down to prevent potential safety hazards. This issue is common in Rinnai water heaters and can be caused by a faulty sensor, improper installation, or damage from environmental factors.
Exhaust Temperature High
Error code 41 on your Rinnai heater indicates that the exhaust temperature has exceeded the safe limit. This could be due to a blockage in the venting system, a faulty temperature sensor, or a problem with the heat exchanger. It's crucial to address this issue promptly to prevent potential damage to your heater and ensure safe operation.
Water Level Circuit Error
Error code 43 on your Rinnai water heater indicates a problem with the water level circuit. This circuit ensures your water heater has enough water to operate safely and efficiently. The most common causes for this error are a faulty water level switch or a low water level in the tank.
Solenoid Valve Failure
Error code 52 on your Rinnai water heater indicates a problem with the solenoid valve, which controls the flow of water into the tank. This valve is activated by the control board when you call for hot water. When it fails, your water heater won't function, displaying this error code. The most common cause is a faulty solenoid valve itself, but other issues like low water pressure or control board problems can also trigger this code.
Bypass Servo Valve Error
The Rinnai 57 error code indicates that there's an issue with the bypass servo valve in your water heater. This valve is responsible for directing water flow between the tank and the heat exchanger. When it malfunctions, it can cause the unit to shut down to prevent overheating or other damage. This error is typically caused by a faulty valve, but it could also be due to a problem with the valve's wiring or control board.
Fan Motor Failure
If your Rinnai water heater displays error code 61, it means the fan motor has failed. The fan motor is responsible for circulating air around the heat exchanger, helping your water heater operate efficiently and safely. When the fan motor fails, the unit shuts down to prevent overheating and potential damage. This error code is specific to Rinnai water heaters and is not typically found in other brands.
Rinnai Code 63 - Excessive Temperature Rise
Rinnai error code 63 indicates an excessive temperature rise within the heat exchanger. The unit's sensors detected the water temperature increasing too quickly, triggering a safety shutdown. This usually means the burner is firing too intensely for the amount of water flowing through the unit. It's a protective measure to prevent scalding, damage to the unit, and potential steam explosions. The unit will lock out and display this error until the problem is resolved. This issue affects the burner assembly, water flow regulation, and temperature sensors within your Rinnai tankless water heater. Ignoring this error can lead to further component damage or even a dangerous situation.
Water Flow Control Valve
Error code 65 on your Rinnai water heater indicates a problem with the water flow control valve. This valve ensures water flows at the correct rate for heating. If it's not working properly, your heater may not function or could overheat, leading to a lockout. This is a yellow hazard level as it's safe to use your heater, but it needs to be fixed by a professional.
PCB Failure
The error code 70 on your Rinnai water heater indicates a failure of the Printed Circuit Board (PCB), which is a critical component of the unit's control system. When the PCB fails, it can cause the water heater to shut down to prevent any further damage. This error is not typically caused by user error and usually requires a professional technician to diagnose and repair.
Gas Valve Circuit Error
The Rinnai 71 error code indicates a problem with the gas valve circuit. This could be due to a faulty gas valve, a wiring issue, or an issue with the control board. The water heater will not operate until the problem is fixed to ensure safety and proper function.
Flame Rod Detection
The Rinnai 72 error code indicates a problem with the flame rod, a crucial safety component in your water heater. The flame rod monitors the burner's ignition and flame stability. When the system detects an issue with the flame rod, it shuts down the burner to prevent potential gas leaks or other hazards. Common causes for this error include a faulty flame rod, a clogged flame arrester, or a problem with the gas supply.
Circuit Board Setting Error
Rinnai's error code 73 indicates a circuit board setting issue in your water heater. This could be due to a software glitch, a faulty board, or incorrect settings. The system might not function optimally, but it's safe to use until a professional resolves the issue.
Fan Current Detection
Error code 79 on your Rinnai water heater indicates a problem with the fan current. The fan is crucial for venting combustion gases and maintaining proper operation. This error might be due to a faulty fan, fan motor, or wiring issue. The digital display will show '79' and the unit will lockout, preventing hot water production until the issue is resolved.
PCB Replace Required
The 'PCB Replace Required' error on your Rinnai water heater means that the main control board (PCB) has detected an issue and needs to be replaced. This could be due to a fault in the board itself or a problem with one of the components it controls. The error is displayed on the digital display, typically as '99'.