Ever wondered about how something on your caravan works, but couldn’t ask because it seemed like one of those simple questions you should have known the answer to all along? Well, wonder no longer. Here you’ll find the answer to some of those questions about your caravan that have always been bugging you. We will be working right through the alphabet, paying particular regard to safety. And whether you are new to the hobby or an old hand, we bet there will be something here that you didn’t know.
Click Here for J to Z

A  IS FOR
AMPS
Amperes – or amps – refer to the quantity of electrical current flowing along an electrical cable. The pressure that pushes it along the cable is measured in volts. Multiplying the volts by the amps gives the amount of energy an appliance uses, expressed in watts (W).
In the UK, normal mains voltage is 230V, though it can vary slightly. The highest amperage of an electrical appliance is 13A, so based on the formula, this becomes 230 x 13, which equals 2990 watts.
The maximum amps available from the hook-up on a UK site is 16A; often it’s less – 10A or 6A. Also, although a nominal 16A may be available, it is unlikely that this amount will reach your caravan if other users are also drawing current.
Hooking up, you need to calculate the total amperage you can draw without tripping out the mains. Add up the wattage of all the appliances and then divide it by 230. Thus a 2kW heater, 125W fridge, 750W kettle, 50W TV, plus two 40W lightbulbs, totals 3005 watts, which, when divided by 230 gives you 13 amps. So if the site’s supply is less than 16A, switch some items off to avoid tripping out the mains.

Accessories
You will need certain essential accessories before you can use your new caravan. Items you will need are a fresh-water container, one or more waste-water containers, plus a length of corrugated waste-water pipe. Sometimes dealers supply a ‘starter pack’ which will contain some, if not all of them. You’ll also need a cylinder of Liquefied Petroleum Gas (LPG) – butane or propane – and, if your van is pre-2004, a butane or propane regulator, plus a hose specifically designed for use with LPG. If your van is an ’04 model, the regulator will be fitted, but you’ll still need the hose which connects the cylinder to the regulator. You’ll also need a 12V leisure battery, which manufacturers never include.

B  IS FOR
BATTERY
Many of the electrical systems in caravans operate on 12 volts, making a 12V leisure battery necessary even if the van also has a 230V mains supply. Leisure batteries supply power over a long period. Most caravans nowadays have a battery compartment, but in some older models the battery is stored under one of the seats. In such cases, it is essential that the hydrogen produced during charging is expelled outside via a vent pipe – usually through the floor.

BRAKING SYSTEMS
The braking system on British caravans is rod-and-cable actuated. The system also incorporates an over-run mechanism connected to the coupling head, which in turn is mounted on a sliding shaft connected to a hydraulic damper. Every time that the caravan tries to catch up with the tow vehicle – during downhill travel, for example, or when tow vehicle’s brakes are applied – the rear of the shaft pushes against a lever which in turn actuates the braking system. The braking system also incorporates a mechanism to deactivate the brakes during reversing.

BREAKAWAY CABLE
By law all caravans must have a breakaway cable to apply the brakes if the caravan becomes uncoupled from its tow vehicle while on the move. After the brakes have been applied, the cable is then designed to break, allowing the caravan to come to a halt away from the tow vehicle. The cable must follow as straight a line as possible to be correctly connected to the tow vehicle. It should pass through a purpose-designed anchor point on the towbar and then be looped back and clipped to itself. If there is no suitable anchor point on the towbar, there is nothing in law to prevent it being looped once round the towball before being clipped back on itself.

BUTANE
Butane liquefied petroleum gas – LPG – is one of two gases used in caravanning. It is supplied in blue cylinders and burns slightly hotter than propane, the other gas. For a given cylinder size you also get slightly more butane than propane. However, butane will not ‘gas’ below 1°C, whereas propane will do so down to -40°C, so butane is unsuitable early and late in the season. Many year-round caravanners, prefer to stick with propane all year.

C  IS FOR
CONSUMER UNIT
The consumer unit is like the fuse box in your home. It comprises the residual current device (RCD) which, in effect, is the main fuse controlling the whole electrical supply, and the miniature circuit breakers (MCBs) which control the individual mains circuits. There is also a test button, which disconnects the mains virtually instantaneously when pressed. Every time the caravan is connected to a mains supply, the test button should be pressed to confirm the system is working.

CONTROL PANEL
The control panel carries all the switches for the 12V equipment in the van. They are likely to be marked: car/off/caravan; water pump; lights; auxiliary circuit; and water heater. The car/off/caravan switch allows the 12V supply to the van to come from the leisure battery, or the car battery, or to be switched off completely when required. The water pump and light switches control exactly those items.
The auxiliary circuit operates such things as the TV booster, radio and 12V socket(s). The water heater switch supplies the power to the gas/electric water heater when it is being used on gas.

D  IS FOR
DELAMINATION
Modern caravan floors and walls are made of sandwich construction. The floors are constituted of upper and lower sheets of thin plywood bonded to a styrofoam core, while the walls comprise the outer aluminium and the inside wallboard bonded to a polystyrene core. If the bond breaks down, delamination takes place. This is more likely to happen to the floor, which then feels spongy. The obvious sign of wall delamination is the aluminium panel bulging outwards. Both forms of delamination can be effectively cured using a specially-formulated epoxy resin.

E  IS FOR
ELECTRICITY
Today, all caravans use 12 volts direct current – DC. Additionally, over the past 20 years or so, 230 volts alternating current – AC – electricity has become standard. The 12V supply comes from the leisure battery and is used to power such items as the lights, water pump, 12V sockets, TV aerial booster and caravan mover if fitted. Theoretically, you can power the 12V equipment using the mains, which is then distributed via the battery charger, but it’s possible that some items may become damaged if powered in this way. The mains is used to power the battery charger, mains lights, fridge, gas/electric water heater, the heating elements in blown-air heating systems and any mains appliances. However, parks and sites often limit the amperage, so it is likely that you will only be able to use a certain number of mains appliances at any one time.

F  IS FOR
FILTERS
Caravan water systems incorporate filters to trap dirt. However, they do not kill the microbes, which is why many caravanners add a biocide, such as Aqua Sol, to the water container every time they fill it.
Some water filters clean all the water entering the caravan, whereas others only deal with the cold supply to the kitchen tap. Whichever type is used, it should always be changed regularly – usually after 4000 litres or annually, whichever milestone comes first.

FLAME FAILURE DEVICE
For the past ten years gas appliances in UK caravans have been fitted with Flame Failure Devices – FFDs. These are mimiscule probes which are heated by the gas flame. As they become hot, they generate a small electrical current which, in turn, keeps the gas valve open. If for any reason the flame goes out, the FFD cools and, in doing so, the current ceases and the gas control valve closes, cutting off the supply of gas to the burner. It takes a few seconds for the FFD to heat up during ignition, which is why it is necessary to hold the gas control knob in when lighting the flame.

FUSES
The 12V DC circuits in the van are controlled by the same types of fuse found in cars – tubular glass and blade. The blade type are usually housed in a fuse block found under one of the seats, or as part of the 12V control panel and are coloured according to their rating: mauve 3, brown 5, red 10, blue 15, yellow 20 and green 30 amps. The glass type are more likely to be found controlling individual items of equipment, their rating being written on a label inside the glass. It pays to know where all the fuses are fitted and to carry spares. One common cause of fuses failing is overloading the circuit, and another is as a result of a short circuit. If the replacement fuse fails instantly, do not use the circuit until the fault has been traced and rectified by a competent electrician.

G  IS FOR
GAS ISOLATION TAPS
In recent years, isolation taps have become the norm, enabling the gas supply to a faulty appliance to be cut off, while allowing the others to continued to be used. No attempt should be made to use a faulty appliance until it has been inspected by a suitably qualified gas technician. All the taps are likely to be found together, often in one of the kitchen cupboards.

GAS REGULATORS
Caravans made before 2004 were supplied without a gas regulator. Two types are available, one suitable for butane LPG, the other for propane LPG. The butane regulator is set for a gas pressure of 28m bar, while the propane one operates at 37m bar. The regulators are also been designed so that they are not interchangeable. However, all the gas appliances in the caravan are suitable for use with both butane and propane without alteration.
From ’04 on, butane and propane supplied throughout the European Community will be at a pressure of 30m bar. As a result, all vans will be supplied with a 30m bar regulator as standard, which can take either gas. However, the two gases do require different types of flexible connecting hoses, so it’s up to buyers to choose which type of gas and hose to use, or to keep both types of hose on board. Regardless of the type of regulator it must be checked regularly by a competent gas technician, since if it fails, it could allow gas at too high a pressure to enter the system.

H  IS FOR
HEATERS
Most vans have space heaters in which the combustion chamber is sealed off from the living area. Hence, no living area oxygen is used, and the carbon monoxide produced during combustion is exhausted outside. Some heaters also have a blown-air option, where the warmed air is fed through ducts around the van by a 12V fan on the back of the heater. Often, the blown-air system incorporates heating elements – up to 2kW – for use when the van is connected to the mains. The number of controls will depend on the sophistication of the heater. Ignition is either push-button or electronic, and these days is incorporated in the temperature control dial, while the blown-air system is operated by a second control. Both are fitted on the top of the heater. If mains elements are fitted, there will be a wall-mounted control panel to enable the owner to set the required power – usually 500, 1000 or 2000 watts – and the desired room temperature. During hot summer days, the fan can be used to circulate cool air throughout the caravan.

HITCH-HEAD
This apparatus is the part of the A-frame, which fits over the towball. There are various models, but they all do the same job: they couple the van and the tow vehicle via the towball. However, it should be noted that in the case of the AKS hitch-head, for instance, a towball with an extended neck is required for correct articulation.

I  IS FOR
INSTABILITY
If the caravan is loaded correctly, with light items stored in the roof lockers, medium items placed in the floor cupboards and under the seats, and heavy items lying over the axle, and it is towed by a well-matched tow vehicle, instability is unlikely to happen. However, such things as a badly-matched outfit, incorrect tyre pressures and travelling too fast – especially downhill – can cause instability and even a dangerous ‘snake’ where the caravan swings in a pendulum motion.