Caravan and Motorhome Gas Safety: Bottles, Regulators, Hoses and Changeover Systems

Gas Safety Guide

A practical guide from Bedam Leisure — caravan & motorhome specialists

Gas is the one system on your van that most owners never touch until it stops working — usually on a cold Friday night, usually with a full awning of people waiting on dinner. It's also the system where the wrong part isn't just inconvenient, it's dangerous. The good news is that the whole thing is simpler than it looks, and almost everything that goes wrong comes down to three parts: the bottle, the hose and the regulator.

Here's how a modern caravan or motorhome gas system actually fits together, what wears out and when, and how to tell which bits on your van are past their date — written for the time of year when you're about to start leaning on the heating properly.

1 The bottle

Propane or butane? In October, there's only one answer

This is the question we field more than any other, and it's genuinely seasonal. Butane won't turn from liquid to gas below about 0°C. That's not a fault or a bad bottle — it's simply the physics of the fuel. Once the cylinder gets cold, the pressure drops away and your heating starts to gasp exactly when you need it most. Propane keeps vaporising down to around −40°C, which is why every experienced winter tourer we know runs propane from about now until Easter.

If you've got a part-used butane bottle sitting in the locker, use it up on the last mild weekend and swap over. It is perfectly normal to run butane in July and propane in November — on any van built to the current standard, the regulator doesn't care.

A quick way to date your van's system: the EN 1949 standard came into force in September 2003 and harmonised both gases at 30 mbar. If your van is from 2004 onwards it will almost certainly have a single 30 mbar regulator bolted to the gas locker wall, and you change gas type simply by changing the pigtail. Older vans carry a regulator that screws onto the bottle itself — 37 mbar for propane, 28–30 mbar for butane — and those two are not interchangeable.

2 The regulator

The bulkhead regulator, and when it's had its day

On a post-2003 van, the regulator is the grey or black lump screwed to the gas locker wall. Its job is to take cylinder pressure — which can be up to 16 bar — and drop it to the steady 30 mbar your fridge, hob and heater are designed to burn. Everything downstream of it is copper or approved pipe in 8 mm or 10 mm, and which one you have decides which replacement regulator you need. Check before you order; it's the single most common cause of a return.

How long does a regulator last? Liquid Gas UK's guidance is that you follow the manufacturer's stated service life, and where that isn't known, replace at 10 years. When buying a new one, check it's less than three years old from its date of manufacture and marked to BS EN 16129. A regulator showing wear, damage or any sign of leakage goes straight away, whatever its age.

The classic failure we see is contamination. Aerosols and oily residues carried over from the cylinder collect in the regulator and gum up the diaphragm, and you'll often spot a yellowish oily fluid weeping around the body. The fix is a new regulator — but the prevention is a gas filter fitted upstream, which is a genuinely worthwhile £70 if you've had one fail before.

3 The hoses

Pigtails age faster than anything else in the locker

The short high-pressure hose between the bottle and the regulator — the pigtail — is the part that wears out first and gets checked least. It lives in a cold, damp box, it gets flexed every time you change a bottle, and rubber perishes. Truma's own advice is the one we give over the counter: bend the hose gently and look at it. If it's brittle, stiff or showing fine cracks, replace it. Don't wait for the date.

On dates: modern hose to BS EN 16436-1 carries a printed expiry date and should not be used beyond it. Older BS 3212 hose carries a manufacture date and has a maximum ten years of service, while the Caravan Club advises replacing low-pressure rubber hose every three years. Whichever standard yours is, if you can't read a date on it at all, it's old enough to change.

The pigtail is also how you switch fuels. Propane bottles in the UK use a POL fitting with a left-hand thread; butane bottles use a clip-on connection. Same regulator, different pigtail.

Tighten it properly, but only just. A POL fitting is a left-hand thread — it does up anticlockwise, which catches people out. Use a correctly sized spanner, never force it, and never over-tighten: crushing the seal is a far more common cause of leaks than under-tightening.

4 Changeover & crash safety

Two bottles, and gas that's safe on the move

If you carry two cylinders, an automatic changeover regulator is the upgrade that makes winter touring civilised. When the working bottle empties, it switches to the spare on its own — no midnight trip out to the locker in the rain — and an indicator tells you which one you're on so you know when to get a refill.

The other half of the story is running gas while you drive, which most motorhomers want for the fridge. That's what the crash sensor regulators are for: Truma's MonoControl CS and DuoControl CS both shut the gas off automatically in an impact. The trigger is set at 4.0 g ±1.0 g, which Truma describes as roughly a 15–20 km/h collision with a solid object, and resetting it afterwards is just a press of the yellow button. Paired with rupture-protected high-pressure hoses, they meet the European requirements for using gas on the move.

5 Detection & servicing

The two things that catch what you can't smell

LPG is heavier than air, which is why gas lockers have those low-level drop-out vents — any escape falls out at floor level rather than filling the van. Keep them clear; we've seen them blocked by everything from a stray levelling block to a well-meaning bit of insulation.

Carbon monoxide is the more insidious risk, because it has no smell at all and comes from incomplete combustion in any fuel-burning appliance. A CO alarm is not optional kit in a van with a gas heater and hob, and it's the cheapest safety item you'll ever buy. Fit it at head height, away from the appliance itself, and check the end-of-life date on the back — sensors expire.

Leave the pressure testing to the workshop. Changing a pigtail or a bulkhead regulator is well within reach of a competent owner, but a full tightness test on the fixed pipework needs proper gauges and belongs in your annual habitation service. If you haven't booked yours, do it now — workshop diaries fill fast through October and November.