How To Fix Hayward Heater BO Code [Explained & Solved]

If a remote thermostat controls your Hayward pool heater, then displaying the bo code on the heater is normal. In this case, you don’t need to do anything to remove this code. 

But if the remote thermostat is not controlling your Hayward heater, then you need to take this error code seriously. The automation system programmed in the heater can cause this error code. You need to get your Hayward heater out of bypass mode to solve it. 

Keep reading this article to know what the Hayward heater bo code is, what causes it, how to put the heater in bo mode and get out of it, and the other Hayward heater common error codes details. 

What Does BO Mean On Hayward Heater?

The bo code in your Hayward heater means bypass operation. Through the bypass operation, the heater bypasses its internal temperature.

After the bypass operation, the remote can control the heater’s set temperature. According to the manual, the Hayward heater error code bo is normal if externally controlled.

Hayward Heater bo Code [Cause & Solution]

The main cause and solution of bo code on your Hayward heater is the following:

Cause: Automation System Programmed In the Heater

You will encounter the Hayward gas pool heater bo code when your heater is wired or programmed into the automation system. This implies that the automation system is now controlling your Hayward heater.

Depending on your Hayward heater’s model, your heater’s automation system may run on due to the following reasons:

  • Programming the logic jumper
  • Flipping a dip switch


To resolve your Hayward pool heater error codes bo, you must ensure that it is not programmed in the automation system. The easy solutions are:

  • Avoid logic jumper programming
  • Make sure the dip switch is not flipping

How Do You Get Out of Automation Program Or Bypass Mode

If your Hayward heater is already programmed in the automation system, you have to get your heater out of bypass mode. To get your heater out of the automation system or bypass mode, follow the steps below:

  • Use the “Mode” key to change your heater’s settings.
  • Select the “Standby” Option and put the heater on it
  • Press the remote’s “Down” key and hold it and then press the Mode key and hold it simultaneously
  • For 3 seconds, hold down both the “Down” and “Mode” keys as long as the “bo” code doesn’t remove from your heater’s display.

How To Put A Hayward Heater In Bo Mode?

For putting your Hayward heater in bo mode, you need to “ON” the STANDBY Mode in your heater. Follow the easy steps below to put your Hayward heater in bo mode. 

  • For placing your Hayward heater in Standby Mode, press the heater’s Mode button 
  • Simultaneously hold the mode buttons and down arrows 
  • Hold both these buttons for 3 seconds to do the Bypass Operation 
  • After 3 seconds, your Hayward heater’s display will show the “bo” message 

3 More Common Hayward Pool Heater Error Codes

From the Hayward pool heater all error codes, here we will explain only some of the main error codes that the users frequently encounter. The most common error codes are: 

1. IO Error Code: Igniter Failure

If your Hayward pool heater’s igniter failed, the heater shows the IO error message on display. 


  • Igniter’s defective wiring 
  • Loose wiring connection 
  • Malfunctioning igniter 
  • The igniter plug and control module is not attached securely 


  • Check the igniter’s faulty wiring and tighten the loose connection 
  • Replace the defective igniter 
  • Ensure secure attachment between the igniter plug and control module 

2. SF Error Code: Temperature Sensor Input Failure

The failed temperature sensor input causes displaying the SF error code on your Hayward heater. 


  • Faulty sensor wiring or connection malfunction  
  • Defective temperature sensor 


  • Check the sensor connection and wiring and replace the faulty one 
  • Replace the bad temperature sensor 
  • Make sure the sensor is properly plugged into the control module’s back 

3. IF Error Code: Ignition Failure

Ignition failure causes displaying the IF error code on your Hayward pool heater. 


  • The closed gas supply shutoff valve 
  • Inadequate gas supply pressure 
  • Defective flame sense wiring or loose connection 
  • Bad gas valve connection or wiring 
  • Blocked gas burners and orifice 
  • Gas valve relay malfunction 


  • Ensure the main gas supply shutoff valve is open 
  • Make sure the gas supply pressure of your heater is between the maximum and minimum value 
  • Replace the faulty flame sensor wiring and bad gas valve relay 
  • Remove the gas burner and orifice’s blockage 

For your better understanding, you can read our ultimate guide on how to fix the IF error code on your Hayward pool heater.


What does HS mean on a Hayward pool heater?

HS on your Hayward pool heater means too high water output temperature. This code means that the heater’s smooth running is facing an issue due to the faulty sensor. The heater should have enough water flow to prevent the water output temperature from getting high.

How do you troubleshoot a pool heater?

To troubleshoot a pool heater, examine its error codes, power sources, and outdoor temperature settings. Also, inspect the heater’s leaks, pilot light, open vent or exhaust, and rust build-up.

Why is my pool heater not working?

Your pool heater is not working mainly due to insufficient air supply, inadequate gas pressure, or improper venting. Also, if you fail to turn on the gas or lack fuel in the tank, all these could stop your pool heater from working.

How do I unlock my Hayward pool heater?

Hold your Hayward pool heater’s lock button until you see the rapid flashes indicator light. Once you see the maximum temperature-lock setting on the digital display, release the button. However, 90 degrees Fahrenheit is the general range of temperature lock settings.


Now you know the details of the Hayward heater bo code, including how to put the heater on bo mode and how to get rid of it. If you see this code on your Hayward heater, optimistically, you will resolve this code issue by yourself.

Still, if you struggle with it and need help, you can comment. We will rapidly give you the solution.

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2 thoughts on “How To Fix Hayward Heater BO Code [Explained & Solved]”

  1. Hi, I’m having a BO code at the heater when it’s in pool or spa mode, when I put it in standby it shows no message. I have tried the low arrow and the mode button but it is doing nothing. Please help me

    • Hi Marcos

      The error code, ‘bO’ stands for bypass operations. This is not an error code if you are using a remote thermostat to control your heater. It’s normal.

      But in case your heater is not controlled through the remote thermostat, this error is a matter of concern and needs attention.

      However, as the heater issue can’t be fixed by the procedure that is mentioned in the article, it would be wise to contact the Hayward customer support center to inspect your heater to fix its BO code problem.

      Best of luck!


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