The Camper Trailer Book – Sample Chapter

Water and internal heating

Installing water and internal heating in a camper trailer is relatively simple to do and increases convenience and comfort, particularly in winter.

A simple but risky way of heating water is to lay 25-30 metres of black 13 mm or 19 mm polythene irrigation hose in the sun – with a valved flow of cold water at one end and a tap at the far end. This is cheap and effective but any remnant water in the pipe can rise to virtually boiling temperature, and spurt out at high pressure when first released. Whilst recommended on web forums, it is not here. The the risk of serious scalding is too high.

Glind heater in vehicle. Pic source unknown

Glind heater in vehicle.

Engine heatingTypified by the Glind unit, this is a cylinder inserted in-line with the engine’s radiator. The heated water/glycol engine radiator fluid is fed via a copper coil inside the cylinder and there transferred to the (pumped) water to be heated.

The downside is that as they transfer heat from the vehicle cooling system, their use is limited to the 15-20 minutes or so before the engine cools down. It thus works fine after driving but not for long after, unless the engine is left running.

 

Gas heating

The Australian Gas Code precludes instantaneous gas heaters being used in any RV excepting Rinnai’s ‘Infinity Internal 20’ unit (intending users need to check personally that this information is still valid). The unit is in any case too large for large for camper trailer use.

LPG powered storage water heaters are fine but even the 14 litre Truma unit is really too big. There are also rigid restrictions on positioning and ventilation. They must be installed by a licensed gas fitter.

In practice, this restricts camper trailer water heating, other than via a camp fire or stove, to the practicable but costly Webasto or Eberspacher (marketed also as Dometic) diesel heaters. Some provide both space and water heating.

A tempering valve (a pre-set mixing valve that dilutes the hot water with cold water) set to 500 C is legally required in Australia. It prevents scalding by the 700 C plus heated water.

 

Space/water heating

As with water heating, gas space heating is rigidly restricted. This is because it can result in lethal carbon monoxide build-up in small spaces. That colourless and odourless gas is produced when any carbon-based substance is burned without combustion being fully complete.

The gas kills because haemoglobin in the blood, that normally transports essential oxygen, grabs 250 parts of it in preference to one single part of oxygen. There are only minor indication: headache, nausea, fatigue – then unconsciousness. It may cause brain damage, even at low concentrations.

If asleep at the time, you may never re-awake. It is a ‘silent killer’ and did that to three caravanners (in Australia) in 2012.

Despite this, forums may advise: ‘invert a flower pot or saucepan over an open gas ring’, ‘turn the oven on with the  door open’, or ‘use a charcoal-burning cooking pot as a space heater’.

All of these actions are potential killers, the last especially so. They are all totally illegal, as is the act of advising others to do so.

Most camper trailer users do without personal heating but it is readily feasible, including for annexes, by using diesel or LP gas fuelled units.

Eberspacher space heater : the Webasto unit is much the same size but a marginally different shape. Pic: Dometic (Aust).

 

 Diesel heating

Relatively simple to install, and light on fuel, Webasto’s and Eberspacher’s diesel heating units have been used in boats and vehicles in Europe since the 1930s.

The two products look and are almost identical and are made in the same small German town. They work virtually identically, and have some parts in common. The following description applies to both. Despite all of this, the two organisations are different entities.

Webasto's Dual Top space/water heater self-installed in the author's Tvan. The radiator-like tank is the water/glycol reservoir. The heat exchanger is the tiny unit at top right. Pic: Author 2006

Webasto’s Dual Top space/water heater self-installed in the author’s Tvan. The radiator-like tank is the water/glycol reservoir. The heat exchanger is the tiny unit at top right. Pic: Author 2006

Both products are available for space heating only, or water heating plus space heating. In both, outside air drawn into a tiny furnace burns injected diesel oil, and exhausts to atmosphere. The furnace has an air space around it enclosed within sealed metal.

In the physically smaller space heating version, outside air is routed through the floor and blown into the heated air space around the furnace.

The now heated fresh air is routed to vents inside the vehicle. The burning fuel is thus totally isolated from the air that is heated.

The water heating unit works as above, but rather than air, a glycol-based fluid is pumped through the unit, heated to a high temperature and circulated through an external calorifier (heat exchanger). There, the heat is transferred to water pumped through it.

A tempering valve (a pre-set mixing valve that dilutes the hot water with cold water) set to 500 C is legally required in Australia. It prevents scalding by the 700 C plus heated water.

Space heating is provided by the hot glycol being routed to one or more fan-enhanced small radiators by heat insulated hoses. The radiators need a 12 volt dc supply.

Fuel is supplied by a tiny electric pump and filter. Both companies offer (the identical) 10 litre plastic tank at extra cost

A small control panel is located wherever it can be conveniently seen and used.

Some exhaust noise is audible outside the vehicle. This is quietened by exhaust and inlet silencers. The units are still a little noisy during their initial few minutes warming up, but are then barely audible even in quiet places.

Even the smallest of (both types) will keep a camper trailer and its annexe amply warm in freezing ambients – often on their lowest temperature setting.

The dual-purpose units supply virtually unlimited hot water within a few minutes of starting.

Webasto Dual Top space/water heater. The Dometic unit (made by Eberspacher) is very similar.

Webasto Dual Top space/water heater. The Dometic unit (made by Eberspacher) is very similar.

 

 

Gas space heating

This unit, from Truma, works in a generally similar way as the diesel units, and is also roughly similar in both size and weight. It is fitted in much the same way also. The unit is claimed by Truma to be approved for RV use in Australia and is stated to generate 2400 watts of heat, at a gas consumption of 170 grams/hour.

As with all such appliances, installation can only be legally done by a licensed fitter.