Problem Center · Boilers
Why Is My Boiler Losing Pressure?
The pressure gauge keeps dropping, or the boiler shows a low-pressure fault.
What could cause this?
- Leaks in piping, valves, radiators or baseboard
- Failed or waterlogged expansion tank
- Relief valve discharging
- Heat exchanger leak
- Air being purged from the system
What you can safely check
- Note the pressure reading cold and while heating
- Look for water around the boiler, relief valve discharge pipe and radiators
- Note how quickly pressure drops
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
Repeatedly refilling a boiler hides the problem and brings in fresh oxygen and minerals that damage it. Request service.
How Air Mechanical diagnoses it
We check the expansion tank, relief valve, fill system and the heating loop to find where the water is going.
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.