Treat as urgent. If gas or CO is genuinely suspected, ventilate, get out, and don't operate switches or naked flames.
What it means
A loud, continuous alarm from the gas detector means it has sensed LPG at a level it considers unsafe. This is not a light to leave and investigate later.
What to do
- Turn off the gas supply at the cylinder immediately.
- Open doors and windows to ventilate - don't use any switches, lighters or naked flames.
- Get everyone out of the van until the gas has cleared and the source is found.
- Get the gas system professionally checked before using any gas appliance again.
Likely causes
- A loose or perished gas hose or joint
- A cylinder connection not fully tightened
- An appliance left on without lighting properly
- A failed regulator
Rough UK cost
A gas system leak check typically costs £60 - £150; repairs vary depending on what's found.