When your Rinnai tankless water heater starts flashing an error code, it’s your system’s way of saying something isn’t right—and that it’s time to call in the pros. While it may be tempting to try and troubleshoot things yourself, tankless water heaters are complex systems that often require professional service to diagnose and resolve issues safely and correctly.
Here’s a closer look at what each error code could mean, and why getting expert help is the best step forward.
If the unit doesn’t respond when hot water is turned on, there could be several possible causes—like a clogged inlet filter, an issue with water flow rate, or valves not functioning properly.
Call for service to have a technician assess water flow, valve function, and internal filter condition to safely restore your hot water.
This code points to mineral buildup inside the heat exchanger—a problem that can quietly damage your system over time. Don’t ignore it just because the heater still works. Call a technician to professionally flush or replace the heat exchanger before it leads to permanent damage.
These codes can signal burner failure during freeze protection, a power interruption during bath fill, or issues with internal valves.
Blockages in your air intake or exhaust can cause serious operational and safety concerns. This is not something to troubleshoot alone.
If your system isn’t igniting, it could be due to gas pressure issues, electrical faults, or sensor problems.
Overheating can damage internal components and is often a result of restricted airflow or water pressure problems.
This issue requires a thorough inspection of all electrical components and grounding paths.
These errors indicate a problem with various temperature or burner sensors—issues that often require component replacement.
From outside temperature sensors to modulating solenoid valves, these components can’t be properly assessed without professional tools.
Rinnai error codes are designed to protect your home and your tankless system. But interpreting and resolving them safely requires training and experience. Whether you’re seeing a single code or multiple flashing warnings, it's always safest to have a professional handle the diagnostics and repairs.