Hayward Pool Heater Error Codes [13 Easy Solutions]

State-of-the-art Hayward Pool Heater has 13 distinctive error codes. They are bD, EE, CE, IO, Sb, SF, H5 or HS, HF, bO, LO, IF, AC, and AO. These Hayward Pool Heater Error codes indicate certain flaws in the heater. 

Solving the issues can be a nasty headache. In this article, you will learn all the solutions to your Hayward Pool Heater errors. Stay tuned…

Hayward Pool Heater Error Codes [13 Easy Solutions]

Follow the said troubleshooting processes to eliminate the error codes:

1. Hayward Pool Heater Error Code ‘bD’

High Voltage on the secondary board can be the possible reason for this code. It can happen if the FC4 Fuse is not open, faulty fuse board, defective transformer, the high voltage output from the fuse board, or such sort. The solution is as follows.


  • Check the FC4 fuse in the fuse board. If it is okay, then make sure that the fuse is not open.
  • Replace the fuse box if it is burned or damaged.
  • Measure the voltage output from the transformer or the harness. If it is somewhat more than 120V AC, then you will have to change the defective component.

2. Hayward Pool Heater Error Code ‘EE’

‘EE’ error code indicated a bad board. This can happen because of a defective control module. To solve this problem follow the said solution.


  • Replace the control module to resolve the issue. 

3. Hayward Pool Heater Error Code ‘CE’

‘CE’ indicated a communication failure between the Control Module and the Display interface. You can either reset the heater to solve the issue. If not resolved, the problem is either in wiring or in the modules.


  • Inspect the wiring. If you find any defective wires, replace that.
  • Detect faulty components such as the control module or the display interface. Change if necessary.

4. Hayward Pool Heater Error Code ‘IO’

‘IO’ stands for ignition failure. It can happen because of faulty wiring or a misplaced connection. A faulty ignitor can be another possible reason.


  • Change the ignitor if it is defective.
  • Check the ignition wiring for any defect. Also, ensure that the ignitor plug is properly attached. 

5. Hayward Pool Heater Error Code ‘Sb’

This is for keypad error. Your keypad can get contaminated if you do not close the protective lid. Dust and water can affect the keys.


  • Replace the keypad 

6. Hayward Pool Heater Error Code ‘SF’

Temperature sensor failure will trigger this error code. It might be because of faulty wiring or a loose connection.


  • Check the sensor for any sort of defect. Change it if necessary.
  • Fix faulty wiring and make sure that the sensor has a proper connection.

7. Hayward Pool Heater Error Code ‘H5/HS’

An error in the water temperature sensor is the reason for the H5 error code on your Hayward pool heater. Wrong settings in the thermostat, restricted water flow, and faulty inlet water temperature sensor can be the possible reasons for this flaw.


  • Make sure that the thermostat is set below 104 degrees. Ensure that the remote thermostat is set to ‘OK’. 
  • Ensure that the heater has an adequate flow of water. It can vary from model to model. Generally, Hayward Pool Heaters needs a flow of 20 GPM to 30 GPM.
  • Measure the water temperature with a regular thermometer. If it is not similar to the inlet thermometer, your inlet water temperature sensor is likely damaged. Change the sensor to eliminate the flaw.

8. Hayward Pool Heater Error Code ‘HF’

A defective gas valve can lead to a flame despite the valve being inactive. In such cases, the error code will appear in the display interface.


Replace the gas valve with a new one

9. Hayward Pool Heater Error Code ‘bO’

The error code, ‘bO’ stands for bypass operations. Our experts do not recommend any bypass terminal for Hayward Pool heaters. However, this code can flash if you are using a remote thermostat. Not to worry, you won’t require any troubleshooting in such cases. But, in a manual thermostat, you will have to set the settings accordingly.


  • Go to the settings using the ‘MODE’ key. 
  • Then select the heater into ‘Standby’. Hold the DOWN key as well as the MODE key for 3 Seconds until the error code is removed from the display.

To know in details about BO code, you can read our comprehensive guide on how to deal with Hayward Heater BO Code.

10. Hayward Pool Heater Error Code ‘LO’

‘LO’ error code will flash for temperature limit switch fault and water pressure switch fault. Now the solution will depend on the heater environment.  


  • If the heater is placed outdoors, then check the water pump. Turn on the water pump to remove the error code.
  • Maintain a steady flow of water. Remove any restrictions to maintain an adequate flow.
  • Check for any faulty or loose connections or wirings. Repair if necessary.
  • Check the filter for any possible blockage. Clear if necessary.
  • Ensure correct water pressure switch settings.
  • If the heater is placed inside, then ensure that the flue has proper ventilation.
  • Ensure that the wire harness terminals are tightened well enough with the temperature limit switch.
  • Inspect the temperature limit switch. Change the switch if necessary.

11. Hayward Pool Heater Error Code ‘IF’

Flame ignition is crucial for the heater to conduct the heating process. However, due to a faulty gas valve or flame sensor and inadequate gas supply, your Hayward Pool heater will show an ‘IF’ error code.


  • Check the connections and the wirings of the gas valve. If the connection is defective, repair or make changes to the gas valve.
  • Check the gas valve relay. If the voltage measurement is not 24V AC, then change the control module. Change the gas valve if the voltage is 24V AC.
  • Check for any blockage or clog in the gas burner and orifice. Clear the restriction to eliminate the problem.
  • Call your local gas suppliers to ensure proper gas pressure.

12. Hayward Pool Heater Error Code ‘AC’

If your blower vacuum switch is faulty or the vacuum switch is defective, then the heater will flash ‘AC’. To resolve this issue, follow the said solutions.


  • Change the defective vacuum switch. 
  • Measure the continuity of the control module across pins 1 and 2 while the blower plug is disconnected. Replace the control module if it is defective.

13. Hayward Pool Heater Error Code ‘AO’

Faulty wiring, defective blower vacuum switch, faulty defective blower relay, and wrong connections can be the reasons for this error code. Follow the solutions to find a fitting remedy. 


  • Fix the defective wiring and wrong connections.
  • Change the faulty components.


How can you reset your Hayward Pool Heater?

Select the ‘MODE’ button from the keypad. Then keep cycling between ‘STANDBY’ and ‘MODE’. Your heater will reset.

Why is my Hayward Pool Heater keep shutting off?

It is because of overheating. Either the vacuum is restricted or the heater has no proper ventilation, your heater can get overheated.

What is the life expectancy of a pool heater?

A pool heater generally lasts for 8 to 11 years.

Wrapping Things Up!

Hopefully, our ultimate guide to Hayward Pool Heater Error codes troubleshooting could fix all the issues with your pool heater. If you still face any sort of difficulty, then reach out in the comment section. 

Our exciting team of experts will help you fix those issues. Till then, enjoy a hot swimming session with your friends and family. 

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