Of all the systems in a caravan, the gas installation is the system which has the potential for being the most dangerous if something goes wrong. Luckily, however, it is rare for anything serious to occur, the most likely problem being a slight leak where the LPG cylinder connects to the caravan's gas pipe. It has happened to us all, having arrived on site, you open the valve on the cylinder only to hear someone say: 'I can smell gas!'

The LPG inside the cylinder is at a much higher pressure than the operating pressure of the various appliances in the caravan, so it is necessary to have a regulator in the system to reduce the pressure as it leaves the cylinder. Prior to 1 September 2003 the regulator screwed onto the valve of the cylinder, and each type of gas had its own regulator which would only fit the appropriate type of cylinder. In the case of the butane (blue) cylinder the regulator was set to 28mbars, while the propane (red) cylinder was set at 37mbars. However, from the 1 September 2003, a new factory-fitted regulator that accepted both butane and propane was introduced in the UK as well as many other European countries. Operating at a pressure of 30mbars, all manufacturers now fit them on the bulkhead of the gas cylinder locker.

To coincide with the new regulator, the connecting flexible pipe, sometimes called a pigtail, changed from the low-pressure type used with the old regulator to a new high-pressure hose. This is supplied complete with the connectors to suit whatever type of gas – butane or propane – is being used in the caravan. In addition to hoses suitable for use with UK cylinders others are available to suit cylinders in other European countries. Importantly, the hoses have the date they left the factory marked on them and Calor – the major LPG supplier in the UK – recommends that they be changed every five years unless, of course, they show signs of deterioration earlier. It goes without saying that if you suspect the hose is faulty, you should turn off the supply at the cylinder and replace the hose before turning the supply on again. If the connections at the cylinder are tight, but you can still smell gas when the valve is opened, check any outlets in the wall of the caravan – for example a barbecue point – and ensure that it is fully closed. If you can still smell gas, the leak could be from a pipe under the vehicle, in which case, you should turn off the gas supply and take the van to your dealer or a CORGI registered gas technician, because crawling around under a van trying to trace a leak can be dangerous. In the case of regulators that fit directly onto the LPG cylinder you will need the appropriate one to suit the cylinder and LPG you are using. However, all regulators that fit directly onto the cylinder can be connected to the van using a low pressure pipe, often secured to the regulator and the van's inlet pipe by jubilee clips. Apart from the advice to change the hose every five years at the most, the other problem which can occur is the diaphragm in the regulator deteriorating and allowing the gas through at too high a pressure. Although it is unlikely that the pressure will become dangerously high, you would be well advised to make sure that the regulator is checked professionally as part of your caravan's service.

In the event of anyone smelling gas inside the van, it is essential to get everyone out and ensure that there are no naked flames around. Then, providing you are not putting yourself at risk, turn off the supply at the cylinder and open all the windows and doors to allow the gas to escape. Bear in mind, however, that both butane and propane are heavier than air and therefore any leaking gas will have dropped down towards the ground. This is the main reason why – particularly on older vans – you'll find gas drop-out holes at junction points in the gas system under the seats, cupboards and the like. Where gas drop-out holes have been fitted they should never be covered or blocked. If you do find that there are draughts coming from them then it is fairly easy to make and fit deflectors to the holes on the underside of the 'van.

The majority of gas pipes in vans are copper and the compression fittings used to join the pipework can sometimes leak. If you suspect that this is the case you can check the joint with leak detecting fluid. All you need to do is turn the supply on to pressurise the system and then use the small brush in the cap of the detector fluid bottle to apply the fluid to the fitting. If you see bubbles, then you know there's a leak. If the compression fitting is leaking slightly, it can usually be tightened by using two spanners, one to hold the main body of the fitting still while using the other to tweak the nut. If that doesn't work, you should isolate the appliance being supplied by the pipe and seek expert help.

See the January 2008 issue of the magazine for this feature article in full.

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