Hayward Pool Heater blower fan/vacuum switch question


New member
Aug 19, 2020
Orange County
I have this Hayward pool heater that threw an AO error. Power is on but it doesn't fire.

The AO says it relates to a vacuum pressure switch, I blew in it and there is no obstruction, and the tubing are not cracked.

A tech came out, he took the heater cover off and manually with a screwdriver turned the blower motor fan, and the heater started. It turned easily.

He told me the fans bad and then told me to replace the heater itself because the fan is expensive (upsell).

My question is, how do I know its not the vacuum switch? He turned the fan and it worked. And if it is the fan obviously the bearing and everything are fine, so wouldn't I just replace the capacitor on the side of the fan instead of replacing the entire fan?

To be honest I think this guy is just trying to sell me a new heater on an easy repair


CPS Reno

In The Industry
Feb 6, 2019
Reno, NV
If this is an H Series heater, the fan is quick and easy. I wouldn't ever just try to change the capacitor, just do the whole fan. You can test the vaccum/pressure switch with a muti-meter. It's just a switch, no continuity in one state, full in the other state.


Well-known member
Mar 30, 2019
Las Vegas, NV
Replacing a blower assembly because of a weak or open capacitor seems a little bit of overkill. Generally motors outlast run capacitors by a good margin and might go through several capacitor replacements during their useful life. Part of the problem is that capacitors that were US made ( and very reliable) pre 90s' were then switched to "assembled in Mexico" at which point their reliability took a hit. Since that time most capacitors are wholly made in China, taking a further hit in reliability. I have experienced brand new units out of the box with weak or open (Made in China) capacitors preventing a motor from running. It is true that replacing an H series heater blower assembly is very easy, but the cost is 10-20 times the cost of a replacement capacitor. Part of the problem with DIY repair of heaters is that most homeowners do not have the full range of test instruments ( or experience ) to quickly identify the source of the problem that technicians who work on systems daily do. Whether to replace just the capacitor or the whole blower assembly would also need to take into account the actual age and usage time of the motor. In order to check the pressure (vacuum) switch ( to determine if the switch has failed or if for some other reason the heater is not creating enough combustion byproducts movement to activate the pressure switch), you would need to know the setpoint for activation of the switch and check the actual reading that the switch is seeing with a manometer ( back to most homeowners not having the test instruments needed ) in order to determine whether the problem was with the switch or the blower assembly or a blockage to flow in the system.
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