Rinnai Tankless Water Heater Error Code 57: How to Fix It
Medium 1-2 hours Medium Severity
Verified June 2026
- Error Code
- 57
- Brand
- Rinnai
- Product Type
- water_heater
- Severity
- Medium
- DIY Difficulty
- Medium
- Estimated Fix Time
- 1-2 hours
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Tools You'll Need
- Phillips screwdriver
- Multimeter
- Gas leak detector spray
How to Fix Error Code 57
-
Turn Off Power and Gas Supply
Always disconnect power and gas before working on the heater to prevent electric shock or gas leaks. -
Access the Solenoid Valve Assembly
-
Inspect Wiring Connections
-
Test the Solenoid Valve with a Multimeter
Be careful not to short the probes together. Ensure the multimeter is set correctly. -
Check the Control Board Output
This step requires the unit to be powered on. Exercise extreme caution to avoid electric shock. Do not touch live components. -
Replace Faulty Solenoid Valve
Ensure gas connections are properly tightened and leak-free. Use a gas leak detector spray to check for leaks after reconnection. -
Replace Control Board (if needed)
Only replace the control board if you have confirmed the solenoid and wiring are fine. Static-sensitive component—ground yourself before handling. -
Test Operation
If error returns, call a professional technician.
Parts You May Need
Solenoid valve (gas) for Rinnai tankless water heater
Check Price on Amazon
Control board for Rinnai tankless water heater
Check Price on Amazon
Solenoid valve (gas) for Rinnai tankless water heater
Check Price on Amazon
Control board for Rinnai tankless water heater
Check Price on Amazon
Solenoid valve (gas) for Rinnai tankless water heater
Check Price on Amazon
Control board for Rinnai tankless water heater
Check Price on Amazon
Solenoid valve (gas) for Rinnai tankless water heater
Check Price on Amazon
Control board for Rinnai tankless water heater
Check Price on Amazon
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When to Call a Professional
If you are uncomfortable working with gas lines or electrical components, or if the error persists after replacing the solenoid valve and control board, call a licensed HVAC technician or Rinnai service professional.Frequently Asked Questions
What does error code 57 mean on a Rinnai water heater?
Error code 57 indicates an open circuit in solenoid valve 4, which controls gas flow to one of the burners. This prevents the heater from operating safely.
Can I continue using my Rinnai water heater with error 57?
No. The heater will shut down and not operate until the error is fixed. Continuing to use it could be dangerous or cause further damage.
How much does it cost to fix error code 57?
If you DIY, a replacement solenoid valve costs about $20-$50. A control board can be $100-$300. Professional repair costs vary but typically range from $150-$400 including parts and labor.
Is error code 57 a common problem?
It is relatively common, especially in older units or areas with hard water that may cause corrosion of wire connections. Regular maintenance can help prevent it.
Can a dirty solenoid cause error 57?
A dirty solenoid can sometimes cause intermittent issues, but error 57 specifically indicates an open circuit, which is usually caused by a broken wire or a faulty solenoid coil.