Boiler display shows LP and shuts down; may be labeled 'Low Pressure'

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Insufficient fill pressure, leaking system, failed automatic fill valve, faulty pressure sensor

Safety first: Allow boiler to cool before adding water.

Steps:

Read pressure gauge: Confirm system pressure is below recommended level.
Add water: Slowly open the manual feed or verify the automatic fill valve is functioning to bring pressure to the correct cold-fill value.
Check expansion tank: A waterlogged expansion tank can cause pressure swings and low readings. Tap the tank; if it sounds solid, it may be full of water and need service or replacement.
Inspect for leaks: Look for visible leaks at the boiler, piping, and radiators.

Medium 3/5

Automatic fill valve

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