Boiler pressure reading zero: is it a leak or a dead gauge

A boiler pressure gauge at zero — the facts that change the job

• A stuck needle can visually mimic total pressure loss
• A gentle tap sometimes frees a needle that has physically stuck
• A gauge that responds normally during refill confirms genuine loss
• A gauge that never moves during refill points to a gauge fault
• Do not run the boiler on an unconfirmed or unresponsive gauge

What we check first with a boiler pressure gauge at zero

A gentle tap on the gauge face sometimes frees a needle that has stuck rather than genuinely dropped, which is worth checking before assuming the worst. If refilling via the loop moves the needle normally and it climbs steadily to the correct figure, the system was genuinely empty and the leak search begins. If the needle does not move at all during a careful refill attempt, the gauge itself is the likely fault and the boiler should not be run until that is confirmed.

Where we deal with this

• Warminster (BA12) · 15 mi
• Bromham (SN15) · 14 mi
• Lansdown (BA1) · 9 mi
• Odd Down (BA2) · 8 mi
• Monkton Combe (BA2) · 10 mi

Questions we get asked

Is it safe to try refilling before calling anyone?

Yes, if you have a filling loop — refill slowly and stop once you reach the correct cold pressure figure.

What if the boiler won't fire at all with the gauge at zero?

That is expected behaviour — most boilers will not run heating or hot water below their minimum pressure threshold.