On many Rinnai tankless water heaters, error code 55 actually indicates an SS (Service Soon) reminder or a mechanical circuit fault depending on the specific model line, requiring a quick reset or professional inspection.
Table of Contents
- What does error code 55 mean on a Rinnai water heater?
- What usually causes error code 55 to appear?
- How do you clear a service soon reminder code 55?
- How do you perform a hard power reset on the unit?
- Which fix matches your specific symptom?
- When should you stop troubleshooting and call a technician?
- What information should you have ready before calling support?
- How can you keep error code 55 from coming back?
What does error code 55 mean on a Rinnai water heater?
Error code 55 on a Rinnai tankless water heater typically appears as a Service Soon reminder or indicates a circuit board or component fault depending on the specific model year.
Because error code meanings can vary significantly across different Rinnai model generations, it is important to check your specific owner manual. On many newer units, the characters resemble an SS maintenance alert for routine flushing.
- Check your owner manual to confirm if code 55 represents a routine maintenance reminder.
- Observe whether the unit continues to supply hot water normally despite showing the code.
- Note if the display alternates with other diagnostic indicators or temperature settings.
- Verify your specific model series, as older units may treat this code differently.
- Confirm whether a recent power surge or internal component error triggered the display.
What usually causes error code 55 to appear?
The most common causes for this code are reaching the preset operational hour threshold for maintenance or encountering an internal electrical circuit anomaly.
Water heaters track operational hours to signal when a system flush is due. Alternatively, transient electrical spikes or sensor communication glitches can prompt the control board to throw this diagnostic code.
- Accumulated operational hours triggering the factory service soon maintenance reminder.
- Transient electrical voltage fluctuations affecting the main computer control board.
- Internal circuit or wiring harness communication errors between components.
- Mineral scale build-up inside the heat exchanger prompting maintenance alerts.
- A temporary glitch in the internal power supply requiring a hard system reboot.
How do you clear a service soon reminder code 55?
You can clear a service maintenance reminder code by performing a specific button sequence on your digital controller panel.
If your unit is functioning properly and the code is simply an hours-based maintenance alert, you can manually clear it without tools. Always ensure your hands are dry before operating the control panel.
- Locate the digital control panel mounted on or near your tankless water heater.
- Press the On/Off button five times within a five-second window.
- Press the On/Off button one additional time to finalize the reset sequence.
- Verify that the digital display clears the code and returns to showing the set water temperature.
How do you perform a hard power reset on the unit?
Performing a hard power reset clears temporary electrical glitches and refreshes the internal control board memory.
Before attempting any electrical reset, ensure you understand basic safety precautions. Unplug the appliance or switch off the dedicated circuit breaker to protect against electrical shock.
- Turn off the hot water taps throughout your home to stop water flow.
- Switch off the dedicated circuit breaker supplying power to the tankless water heater.
- Unplug the power cord from the wall outlet if your unit is plugged into one.
- Wait at least five full minutes to allow all internal capacitors to fully discharge.
- Plug the unit back in or turn the circuit breaker back on to restore power.
- Verify that the system restarts successfully and check if the error code remains visible.
Which fix matches your specific symptom?
Use this quick reference table to match your unit operational behavior with the most likely cause and appropriate fix.
| Symptom | Likely cause / fix |
|---|---|
| Hot water works fine | Service reminder; use button reset sequence |
| Code returns after reset | Control board glitch; try full power cycle |
| Unit fails to ignite | Component fault; call licensed technician |
| Display flashes erratically | Power supply issue; check breaker panel |
When should you stop troubleshooting and call a technician?
You should stop DIY troubleshooting and call a licensed professional immediately if you smell gas, observe water leaks, or encounter persistent electrical faults.
Gas appliances involve severe safety hazards. Any work involving gas valves, sealed combustion chambers, or electrical wiring requires certified expertise to prevent property damage or personal injury.
- Stop immediately and shut off the gas supply if you detect any gas odor.
- Call a professional if error code 55 persists despite multiple power resets.
- Contact a technician if you notice water leaking around internal electrical components.
- Never attempt to repair, modify, or replace internal gas valves or control boards yourself.
- Seek certified assistance if the appliance fails to ignite or produce hot water.
What information should you have ready before calling support?
Having your exact appliance model number, serial number, and a record of troubleshooting steps ready will speed up professional service.
Technicians and manufacturer support lines need precise details to diagnose water heater issues efficiently. Locate your rating plate before placing a service call.
- Locate the rating plate on the side of the unit to record the exact model and serial number.
- Note the installation date and check if your appliance is still covered under manufacturer warranty.
- Write down a clear timeline of when error code 55 first appeared.
- List all the specific troubleshooting steps and resets you have already attempted.
- Describe whether the unit is still producing hot water or completely shut down.
How can you keep error code 55 from coming back?
You can prevent recurring maintenance codes and protect your water heater by scheduling annual system flushes and checking air filters.
Routine preventive maintenance extends the lifespan of tankless water heaters and prevents unexpected shutdowns. Keeping intake filters clean ensures optimal combustion airflow.
- Flush the heat exchanger annually to clear out harmful mineral scale build-up.
- Inspect and clean the air intake filter regularly to maintain proper airflow.
- Protect your home electrical supply with a surge protector rated for tankless units.
- Monitor your water heater display periodically for early warning indicators.
- Review your owner manual guidelines for seasonal maintenance recommendations.
Frequently Asked Questions
What should I do if clearing the service reminder code does not work?
If the reset sequence fails to clear the display, perform a complete power cycle by turning off the circuit breaker for five minutes. If the code persists after restoring power, it may indicate a deeper electronic fault requiring manufacturer support or professional technician service.
Can I keep using my hot water heater while error code 55 is displayed?
In many cases where code 55 acts as a service reminder, the water heater will continue to function normally and provide hot water. However, you should verify your specific owner manual or manufacturer support page to ensure safe operation before continued use.
Does error code 55 mean my water heater is broken?
Not necessarily. On many Rinnai models, code 55 is designed to look like the letters SS, standing for Service Soon. It functions as a scheduled reminder for routine maintenance rather than an indication of a critical mechanical failure.
How often does a Rinnai tankless water heater need to be flushed?
Rinnai generally recommends flushing the heat exchanger at least once a year, or more frequently if you live in an area with hard water. Regular flushing prevents mineral scale accumulation and reduces the likelihood of recurring error codes.
Who should I contact if my Rinnai water heater requires major repairs?
You should contact a licensed local plumber who specializes in tankless water heater service, or reach out directly to Rinnai customer support to find a certified technician in your local area.
Bottom Line
Start by checking your owner manual to confirm what error code 55 signifies for your specific model series. If the unit continues to run normally, perform the controller reset sequence to clear the service reminder.
Sources
- Rinnai installation manual
- Rinnai owner manual
- Manufacturer support page
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