I have a Hayward H400FDN heater that I've had for 10 years and this season it will not ignite. When I turn it on, the blower turns on, runs for a few seconds, then I hear the click it makes when about to ignite, but there's no ignition. The blower keeps blowing and it repeats that cycle two more times and then the IF code is displayed. The igniter resistance is good and the voltage to the gas valve is good when trying to ignite -- it goes to 27-28 volts for a few seconds and then back to 0-ish.. The inlet static and load pressure at the gas valve is 10 WC (which is what Hayward calls for), but I'm not getting any manifold pressure when the heater tries to ignite.
The only troubleshooting suggestion I've found for good inlet pressure and low manifold pressure is to increase the manifold pressure at the valve, but adjusting that screw doesn't help.
Does this mean the gas valve is bad? Or could it be something else? All the wiring looks good, and I'm not getting any other error codes, but could this be caused by a bad control board?
The only troubleshooting suggestion I've found for good inlet pressure and low manifold pressure is to increase the manifold pressure at the valve, but adjusting that screw doesn't help.
Does this mean the gas valve is bad? Or could it be something else? All the wiring looks good, and I'm not getting any other error codes, but could this be caused by a bad control board?
