Just want to pass on this fix on a Jandy Spa/Pool heater (400 LXi) after a flood where the heater sat in 5 inches of water.
About 2 months after the flood, I tried to start the heater for the first time, and it would not start, giving me an Ignition Lockout fault. After the electronics checked out okay, I finally decided to remove the gas manifold, since this was really the only part that was under water.
The manifold still had water it in (black gunky water). The manifold has 8 jets, with 3 very small orifices in each jet. About 90% of these small orifices were plugged. I unscrewed the jets, and cleaned out the orifices and the manifold.
I reassembled the jets into the manifold and reinstalled the manifold. The heater started up the first time and worked ever since.