Problem Center · Navien
Why Is My Navien Boiler Losing Pressure?
Your Navien boiler’s pressure keeps dropping or shows a low-pressure error.
What could cause this?
- Expansion tank failure
- Relief valve discharge
- System leaks
- Fill valve problems
What you can safely check
- Note the pressure reading and how quickly it drops
- Look for water at the relief valve discharge and around the unit
Don't open electrical panels or equipment cabinets, handle refrigerant, work on gas or combustion components, or bypass safety controls.
When it requires a professional
Repeated refilling hides the leak. Request service.
How Air Mechanical diagnoses it
We check the expansion tank, relief valve, fill and the heating system for the source.
Every diagnosis starts with the system as it actually exists — equipment, controls, wiring and installation. The equipment has a brand. The problem has a solution.