BoilerFaultCodesYour boiler has stopped working because it cannot accurately measure the water pressure due to a sensor or wiring issue.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Pressure sensor fault
What causes this fault?
This fault occurs when the boiler's internal computer loses communication with the water pressure sensor, meaning it can no longer tell if there is enough water to operate safely. The most common reason is that the sensor itself has developed an electrical internal short or has become blocked by system debris, though it can also be caused by damaged or loose wiring between the sensor and the main control board.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like F73 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Glow-worm Flexicom 18sx is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.