Heater's flue terminal shows white staining and excessive condensate dripping.

Safety first: Turn off power and gas before inspecting the flue. Condensate can be acidic; wear gloves.

Step-by-step checks:

• Check operating conditions: Very cold pool water and low return temperatures can cause condensation. This may be normal to some extent, but excessive dripping should be addressed.
• Inspect flue slope and drains: Ensure the flue is properly sloped back to the heater or to a condensate drain, as specified by Pahlen.
• Insulate flue (if allowed): In cold climates, insulating the flue (per code and manufacturer instructions) can reduce condensation.
• Check combustion: A technician should verify combustion efficiency and adjust gas/air ratio if needed.

When to stop: Persistent heavy condensate can damage the heater and flue; have a professional evaluate the installation.