Jacuzzi pool heater shows F6 and shuts down; may occur during windy conditions or with long vent runs.

Safety first: Turn off power and gas. High flue temperatures can be dangerous and indicate venting problems.

Steps to troubleshoot F6:

• Inspect venting: Verify that the vent pipe size, material, and length match Jacuzzi installation requirements. Look for sags, dips, or crushed sections that could restrict flow.
• Check for obstructions: Remove the vent termination cap (if safe to do so) and inspect for bird nests, debris, or corrosion buildup. Clean or replace sections as needed.
• Inspect flue temperature sensor: Locate the flue temperature sensor (often mounted in the exhaust collector). Check wiring for heat damage or loose connections. Test resistance against Jacuzzi specifications; replace if out of range.
• Check for heat exchanger restriction: A partially blocked heat exchanger can drive flue temperatures up. Look for signs of soot or corrosion. A professional should clean or replace the heat exchanger if restricted.

Do not operate the heater until the cause of F6 is corrected. Have a qualified Jacuzzi technician verify safe operation after repairs.