Hayward Pool Heater Error Code 11: How to Fix It

Medium 1-2 hours Medium Severity Verified June 2026
Error Code
11
Brand
Hayward
Product Type
pool_equipment
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
1-2 hours
Error code 11 on your Hayward pool heater indicates a stack flue switch fault. This means the heater has detected a problem with the exhaust flue, often caused by a dirty or blocked flue, a faulty flue switch, or a malfunctioning ignition. Follow these steps to diagnose and resolve the issue.
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Tools You'll Need

How to Fix Error Code 11

  1. Safety First: Power Off and Check Gas

    Always turn off power and gas before servicing. If you smell gas, leave the area and call a professional immediately.
  2. Inspect the Flue and Exhaust Stack for Blockages

  3. Test the Flue Switch

  4. Inspect and Clean the Burner Assembly

  5. Check the Ignition and Flame Sensor

  6. Reset the Heater and Test

    If the heater fails to start or error persists, turn off the system and consult a licensed technician.

Parts You May Need

O-ring/gasket for flue stack
Check Price on Amazon
O-ring/gasket for flue stack
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O-ring/gasket for flue stack
Check Price on Amazon
O-ring/gasket for flue stack
Check Price on Amazon
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When to Call a Professional

If you are uncomfortable working with gas or electrical components, or if cleaning and replacing the flue switch does not resolve the error, call a licensed pool heater technician. Persistent error code 11 may indicate a serious combustion problem or control board failure.

Frequently Asked Questions

What does error code 11 mean on a Hayward pool heater?
Error code 11 indicates a stack flue switch fault. The heater's sensor has detected a problem with the exhaust flue, often due to blockage, a faulty switch, or ignition issues.
How do I reset a Hayward pool heater after error code 11?
Turn off the heater and disconnect power for 30 seconds. Reconnect power and press the appropriate reset button on the control board (if available). If the error returns, further troubleshooting is needed.
Can I bypass the flue switch on a Hayward pool heater?
No. Bypassing the flue switch is dangerous and can lead to carbon monoxide poisoning or fire. Always address the root cause.
How much does it cost to fix a flue switch on a Hayward pool heater?
A replacement flue switch costs around $20-$50. If you hire a professional, expect labor costs of $100-$200.
Why does my Hayward pool heater keep showing error code 11?
Recurring error 11 often indicates a persistent blockage in the flue, a failing flue switch, or a dirty burner assembly causing soot buildup. Thorough cleaning and part replacement usually fix it.