Navien furnace frequently loses pressure and requires frequent refilling

Safety: Turn off power and allow system to cool before inspecting for leaks.

• Inspect visible piping: Look for damp spots, corrosion, or staining on pipes, fittings, and around radiators or manifolds.
• Check relief valve: Examine the discharge pipe from the pressure relief valve for signs of water. If it drips regularly, test system pressure and replace the relief valve or expansion tank as needed.
• Test expansion tank: Isolate and drain the expansion tank, then measure air charge with a tire gauge. Recharge to the specified pressure or replace if the bladder has failed.
• Monitor pressure: After refilling and bleeding air, monitor pressure over several days. If it continues to drop with no visible leaks, a professional leak detection service may be required.