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Rod, Systems Engineer
Category: Consumer Electronics
Satisfied Customers: 4501
Experience:  FCC Commercial Licenses, BSCS, ASEET, 40+years Electronics & Communication Systems
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The control board for my Hayward pool heater has malfunctioned.

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The control board for my Hayward pool heater has malfunctioned. I am guessing an onboard relay is defective. Should be sending 24VAC to the gas control valve, but is not.

Any suggestions for repairing this type of defect?
Hi George,

I will try to assist. Hayward intends for the control board to be replaced when it fails, there are no service schematics available for the control board. Relays, have a diode across the coil to prevent voltage surges when the relay de-energizes, look for a diode near the coil connections on the circuit board - if the diode is shorted - the coil will not energize. Also, there may be a switching transistor that provides the "ground" connection for the coil to complete the circuit - the transistor may have failed. There are some fuses on the control board that should be checked also. But if one has blown, and you replace it and it blows again - then the board should be replaced.

A replacement control module can be purchased here.

Hope this helps.

Rod and 2 other Consumer Electronics Specialists are ready to help you
Customer: replied 7 years ago.

Hi Rod-


Thanks for your help. I figured the control board could not be replaced.


Two items of feedback:


1. The Accept Answer button is not green, but the instructions say to click the green ACCEPT icon.


2. The weblink you put in your answer is not the corrrect item My control module is a circuit board with several pins out for plug on connectors to the various items that need controlling.


Which makes me wonder If I've described the issue correctly?


In any event, I'm accepting the answer and I thank you for your help.



Hi George,

I'm sorry that was the wrong board, I checked another supplier and one is listed here - see if its the correct one - the other listed that number, but might have mismatched it.

Customer: replied 7 years ago.

That looks a lot closer. Thanks for the help.



Hi George,

Glad to help. Look at your control board and there should be a part number on it. Hayward did do an upgrade to the H400 models after 2004, with the control boards.