Understanding How The Fiamma A20 Expansion Tank Works
Accumulators or expansion tanks are small units with internal pressurised diaphragms which is like a balloon pumped full of air. The balloon is set at just under your system pressure and applies a constant force on the water. The water entering the expansion tank from the water pump is pulsating and the accumulator smooths this out into a constant pressure.
When the system is has reached its desired pressure the water pump will shut off. When the user opens a tap or switches on the shower the system pressure will drop. The water pump can sense the pressure drop and will kick in. The expansion tank will also help even out the follow of water during the short periods between the tap opening and the water pump kicking in.
Without an expansion tank, water can surge through your system in an uncontrolled way and put strain on your pipe and fittings - think sputtering water bursting out of your kitchen tap! This would ultimately decrease the lifespan of your system. The most common expansion tanks we sell are the Fiamma A20. It is the best expansion tank for balancing cost and performance.
The expansion tank is connected directly after your water pump (on the 'demand side') and then to your water pipe, which runs to your various outlets such as your kitchen tap and shower mixer.
How To Pump Up Fiamma A20 Expansion Tank
Pumping up the Fiamma A20 expansion tank is straightforward. Simply unscrew the top cap to reveal a brass valve. Then connect a bike pump (either a floor standing or hand pump) to the A20 valve and pump away!! The pressure of the expansion tank must be just below the system pressure. This means if you have bought a 30 PSI pump the A20 should be around 28 PSI. If you have bought a 20 PSI pump you should have the A20 pumped up to around 18 PSI.
Water Pump Information
Water Pumps in Campervans & Motorhomes
Water pumps are used to transport water through a system. They sense pressure drops in a van’s plumbing system when a tap is opened, supplying water only when needed. Most water pumps used in these settings are 'diaphragm' pumps, which use the reciprocating movement of a diaphragm to alter the pressure on either side of the pump, to pump water through a system. They are 'self-priming' which means they excel at running dry for short periods without damaging themselves. The chamber of a diaphragm pump contains non-return check valves to force water to flow in only one direction and prevent backflow.
Motorhomes, campervans, caravans and boats usually use 12 volt pumps (and sometimes 24 volt - see our 'electrics' page for more information) using DC (rather than AC) power supply - so they are perfect for connecting up to a 12 volt leisure battery and accompanying DC electrics system. 12 volt water pumps have low amp (or current) draw, and are very quiet when in use.
The advantages of the Shurflo Trail King water pump and why we include it in our Campervan Water System Bundles
Outer Land Supplies water bundles come with the Shurflo Trail King water pump or the Fiamma Aqua F water pump.
The Shurflo water pump is a fantastic, very popular and has been built for campervan and motorhomes in mind. Here is a round up of why we think it works well in campervans:
The water pump has rubberised feet to absorb the vibrations of the pump
Good price point and a good balance of durability, cost and performance
It has a built-in non-return check valve so water is prevented from flowing through the pump the wrong way
It automatically turns on and off when a tap is opened and closed
3 chamber diaphragm for smooth pumping action
½” BSP threaded fittings which means you can attach John Guest fittings to each end of it (as per our schematic)
It is available is 12V and 24V (our bundles are all 12V however we do have stock of 24V pumps for bespoke orders)
Available in 20 PSI and 30 PSI
Understanding Pressure & Flow Rates
Water pressure is measured in 'PSI', or pounds per square inch, and represents the force at which water enters your system. We offer 20psi or 30psi pumps. For larger water systems, particularly where you have a longer van or are running more water pipe, the 30psi pump is appropriate. Shurflo do offer 45psi pumps but for most set-ups this will not be required.
Flow rate is the measurement of how many litres of water could potentially come out of your tap per minute. So, a 7L water pump provides 7 litres of water through your tap each minute, whereas a 10L pump provides 10 litres.
Shurflo Filters Everything You Need To Know!
Water filters stop debris and other particles entering your water pump and the rest of your system from your fresh water tank. Shurflo make solid, easy-to-clean filters that screw directly onto the Shurflo water pumps. They have a clear cover so it's easy to see when it is time to clean. The filter piece can be easily cleaned when needed.
What orientation should the filter be in?
We recommend that the filter is positioned so the clear plastic cover is facing down. This means that if and when particles are filtered out they collect away from the flow of clean water. If the filter was the other way around dirt particles would always be settling directly in the flow of the water.
How to clean the water pump filter?
The filter is made up of 3 parts: the main plastic body, the clear plastic cover and a metal strainer/filter. To disassemble the filter simple twist and unscrew the clear plastic cover. Once separated you can now clean the metal strainer and reassemble! We suggest installing in line valves either side of your filter/pump/expansion tank set up so you can isolate your water supply and access those units for any cleaning or maintenance that might be required.
