System overview
Our truck is fairly well insulated with 60mm of insulation, albeit with some inevitable cold-bridges where the ply is mounted to the steel frame. On each side of the steel frame is a layer of 3mm neoprene tape which will help reduce conduction between the outer aluminium skin and the inner plywood.
We designed the truck with a trip to southern Africa in mind so extreme sub-zero temperatures are not our concern. It can get fairly cold in the desert at night so we wanted to be able to heat the habitation box at night.
We designed the truck with a trip to southern Africa in mind so extreme sub-zero temperatures are not our concern. It can get fairly cold in the desert at night so we wanted to be able to heat the habitation box at night.
Heater choice
A diesel heater is the obvious choice as we already carry hundreds of litres of it and it's widely available. There are two types of diesel heaters:
Webasto and Eberspacher are the two big names in diesel heaters but these start at about £600 for a used system and much more for a new or refurbished one. Parts are also expensive and a new fuel pump will cost upwards of £100.
On eBay there are dozens of Chinese suppliers selling Diesel air heaters and £150 will buy a 24V 5kW kit complete with fuel pump, tank, heater, controller, and wiring loom. After much research, we decided to take a risk and buy one of these. Theoretically we could buy 3 replacements for less than the cost of a Webasto.
- Air heaters - where diesel is burned and air is passed over a heat exchanger providing a source of hot air
- Water heaters - where diesel is burned and water is passed through a heat exchanger which you can then run to radiators, exchangers etc. The advantage of a water heater is that you can use it to heat your hot water.
Webasto and Eberspacher are the two big names in diesel heaters but these start at about £600 for a used system and much more for a new or refurbished one. Parts are also expensive and a new fuel pump will cost upwards of £100.
On eBay there are dozens of Chinese suppliers selling Diesel air heaters and £150 will buy a 24V 5kW kit complete with fuel pump, tank, heater, controller, and wiring loom. After much research, we decided to take a risk and buy one of these. Theoretically we could buy 3 replacements for less than the cost of a Webasto.
Mounting
Diesel heaters are surprisingly noisy. Although they are designed to be mounted inside the vehicle, we opted to mount ours in a box underneath the load bed mounted to the chassis. This should reduce noise and be safer in the event of a malfunction. The Leyland DAF T244 comes with a steel box in the cab behind the drivers seat that is perfectly sized to house one of these heaters, so this was removed and re-purposed. I cut a hole and included a plastic flyscreen at the intake end.
Heater mounted in ammo box
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The fuel tank was mounted on the rear left mudflap. This allows it to be easily filled when fuelling up the main fuel tank, and the slight angle causes sediment to settle lower than the intake.
In line fuel filter installed
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Sediment caught at the bottom (black sludge / diesel pest)
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Inside the habitation box, the vents can be directed anywhere using flexible tubing. The tubes get very hot so use metal ones, not plastic. We opted for a simple vent that heats the cab and the bathroom using the space between the cassette toilet and the bathroom wall.
Update
After a few months of using the following things have been discovered:
1. My kit came without a fuel filter. The translucent nature of the fuel tank means that it is very susceptible to diesel pest. Put an in line filter before the fuel pump. If you didn't and your furl pump gets stuck, blow through it (forwards, not backwards) with an air hose. We didn't use our heater for a few months (because it was 30+ degrees C) and the fuel developed a black sludge.
2. There is a facebook group called "chinese diesel vehicle air heaters" that is a great source for troubleshooting.
3. The downside to mounting under the habitation box is that it reduces wading depth. Spray and dust has not been an issue however but consider crossing a deep river.
4. The units are either 12v or 24v and are not able to be modified after purchase. They also draw a LOT of power (10+ amps) for a few minutes on startup. Bear this in mind.
After a few months of using the following things have been discovered:
1. My kit came without a fuel filter. The translucent nature of the fuel tank means that it is very susceptible to diesel pest. Put an in line filter before the fuel pump. If you didn't and your furl pump gets stuck, blow through it (forwards, not backwards) with an air hose. We didn't use our heater for a few months (because it was 30+ degrees C) and the fuel developed a black sludge.
2. There is a facebook group called "chinese diesel vehicle air heaters" that is a great source for troubleshooting.
3. The downside to mounting under the habitation box is that it reduces wading depth. Spray and dust has not been an issue however but consider crossing a deep river.
4. The units are either 12v or 24v and are not able to be modified after purchase. They also draw a LOT of power (10+ amps) for a few minutes on startup. Bear this in mind.