Easy hot water – diesel hot water system in off-road caravan

kimberley off-road caravans blog header offroad caravan hot shower anywhereTaking lots of water with your lightweight off-road caravan adds a lot of extra weight. You can travel with less water with a Kimberley between filling stops using our integrated diesel hot water system. Water weighs 1 kg per litre, so carrying 200 litres of water adds 200kg to your weight. Yet water can be the scarcest commodity at times and we should always carry more than we think we need. Most travellers carry multiple water tanks. One for pure drinking water and one for showers and washing up. The second tank may be filled with whatever water can be sourced on the way. Additional tanks can be fitted for additional water. This can lead to a challenging problem of carrying so much extra weight - so we asked ourselves "Is there an alternative to this?" offroad caravan with owner hot waterYes! There is a third option to help you reduce the amount of water weight you need to carry on your off-road caravan. Pump from a stream or billabong. What this does is expand your available water to potentially an endless supply while camping. Yes, endless hot showers! (assuming your grey water tank is set to run off, or you are outside!). This significantly changes the effective on-board capacity when camping. It also means that if you are travelling to a location with known available water, you don't need to travel with as much water on board. You can travel lighter! offroad caravan happy owners

Is there a catch? The issue becomes one of how big is your grey water tank? In fact the trend is to have 2 grey water tanks on board. One for reclaimed water from the shower, the other for the rest.

Pumping from a stream or billabong through an LPG-based hot water system presents some practical problems. LPG-based hot water systems rely on the water passing through thin plates with the LPG flame heating these plates. If the water has any sediment or stray material, these plates may become easily blocked. Once these heating plates become blocked hot water performance is severely depleted.

But it can be done with the Diesel Hot Water system used in Kimberley off-road caravans! Diesel-based hotwater systems heat glycol which passes through an industrial heat exchanger (we source stainless steel units from Sweden). There is no issue if the water has any residue or particulate in it. This is filtered at both ends: on the input side and a final filter before the tap. The water system can be flushed clean under pressure at any time. kimberley off road caravan hot water diesel hot water diagram Image above: This is a diagram of the type of diesel burner used in the Kimberley Diesel Hot Water System. Heat Storage Fluid (Glycol- the aqua coloured path) flows into the unit and passes through a heating jacket. This hot Glycol is then passed through a heat exchanger unit where it heats the water. kimberley off road diesel hot water system offroad caravan camping The other issue is that you don't want to be filling a tank in one operation from the stream and then using the tank. This is laborious. A single switched system is far easier to use. With the use of heat exchangers, not only is the hot water virtually instantaneous (55°C in less than 5 minutes in most cases) but to switch to a stream or billabong is simply a matter of turning 2 valves and dropping the hose in. With the Kimberley system you can park near a creek and run endless hot water using the outside shower to clean down nearly anything... preferably it is all natural material! Separate or Connecting Water Tanks? We have to report the terrible story of a camper trailer customer who were on a long trip off the beaten track. They had “taps” fitted to the drain of both water tanks. After an overnight stop and a brief hike during the day, they returned to find both taps had been turned “open” by mischieveous visitors. offroad caravan with porsche At Kimberley we now only fit a “tap” to the drain on one tank and require a spanner to remove the “bung” on the second tank. The 2 tanks are not connected! Our principles of water storage:
  • Dual tanks, dual water fillers, dual hoses
  • Lockable and secure water fillers
  • Separate town water or stream water inlet that can bypass the main water tank
  • Water for hot water tank to be stainless water tank/ hot water tank/ buffer tank. The tanks can be rinsed with town water if they become contaminated.
  • Can pump (potable) water out of a stream
  • Sink drains through small outlet so a drain hose can be connected if desired
outside kitchen with offroad caravanYour typical water use pattern may be:
  • Keep one water tank with good drinking water as full as possible.
  • Carry only enough water in the second tank as you need from filling point to filling point (this may be bore water) – typically from 30L to full.
  • Always carry an emergency Jerry Can of water on the front.
  • Use hot shower generously when available bore water
  • “Navy wash” when bore water is limited
  • Use hot “shower” drain water for washing clothes when bore water is scarce.
  • Check water meter levels daily
There are some other items you should look for on a lightweight off-road caravan: Is there a water filter? YES - Most Kimberley models are fitted with a filter on the cold water supply. The unit we provide has the silver eliminating bacteria system. It is only provided on the cold water so that there is sufficient water flow in the hot system for the heat exchanger to work. How can I fill up from a local stream? There are 3 steps:
  • Attach a long enough hose (we recommend a 20mm hose with a small in-line foot valve) with the valve in the stream
  • Turn the water source valves to bypass the water tank and take the stream water into the pump and hot water heater.
  • Turn on the tap!
The water pressure and flow will reduce. At a 3.5m lift, we found the pressure and water flow to be approx half that from the tank. It was still a quite acceptable 5 litres/min What if I suddenly discover the stream water is unclean or non-potable? You have to flush the hot water tank and the lines but do not have to worry about the tank. You have to flush the lines before turning the valves back to the tank to prevent backwash into the tank. How much will it cost me to run a diesel-powered hot water system? The cost is low, low, low. Many of our customers achieve 3 months of hot water for less than $20 in diesel!
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