Jandy JXI 400N Ignition Fault

[TBone2000]

I have been struggling to troubleshoot the cause of my ignition fault. When the heater first failed the blower would still run. I replaced the Air Pressure switch and Hot Surface Ignitor. I did see glow on the hot surface ignitor,but my burners would not stay on for longer than 7 seconds. I had a replacement Fenwal ignition control and replaced that. No change. Frustrated, I relucantly called my Pool Service Tech.
His initial diagnosis was that the Fenwal ignition control was bad. Then he called Jandy. He bypassed the Blue/Black wire (to blower) F1/F2 and the blower worked. So he replaced the Power Distruibution Board (PDB) with a new board. This New PDB board failed to solve the issue so he told me I needed a new Fenwal Ignition Control. He removed the New PDB.
Over the weekend, I rechecked Steps 1 through 12 on the JXi Troubleshooting guide. Step 12, there is 120 between F2 and ground but the blower is still not on. The Voltage between F1 and ground (white wire) on the Blower harness is zero. When it should be 240v. Inspection of the connection/pins/undersurface of the PDB board and interface card does not show any sign of corosion/burn/damage. Ohms test of disconnected black wire/white wire on the blower harness was NOT OL. I suspect that the connector and/or wire is the culprit. Any other thoughts?
The Blower harness wiring is one piece, I do not see a replacement part for this. Do I need to replace the wiring and connector? If so please walk me through this processs.
I see that there is a capacitor in the blower, could this have anything to do with this failure? Purpose of the red/yellow and blue wires to the Blower?

 

[setsailsoon]

T-bone,

Problem you are describing indicates everything is actually working except after you go through the ignition cycle the fenwell looks for verification of a flame. If it does not get that it closes the gas valve. Most likely your issue is in the flame detect circuit. Flame detection circuit can be very sensitive since it is only looking for micro amp current flow through the ionized portion of the flame. If there is a flame the ionized gas will allow microamps to flow to ground. If not the logic in the Fenwal turns off the gas valve. Often the failure it's in the ground circuit from the flame detect probe. I would start there. Has there been any lightning activity or anything else that happened to the heater recently? These things are so sensitive to current leak in the ground system that you can actually have leakage that is not easy to detect and you think you have good power. This happened to me after a lightning strike and I found tiny pin holes barely visible in the conductors inside the supply Power wires. It is pretty easy to check this. Just run a temporary wire from the power connector back to the breaker in the Box and disconnect the other wire. If that's not likely then I would bet your problem is in the ground for the flame detect circuit. There is a kit available to run a spare ground wire to the frame near the blower housing. Or you can fabricate this yourself but be sure to use wire with the high temperature silicone insulation.

I hope this is helpful.

Chris