I am interested in finding out more about the NRV and the boiler, for which both are difficult to get to as they are under a part of the seating that is fixed down.

Bob my van was new and did as I explained above. I put it down to a pants seal on the o ring. Once up and running I then adjusted up as mentioned above and I've never had to adjust it since. one problem exists however with the pressure sensed system, this is of course obvious!!! and that is the pump will continue to run even after the taps turned off, until the water pressure rises to a predetermined level and as a consequence will also turn the pump on if the pressure drops for other reasons. You wont do any damage if you try adjusting the pressure switch a little above or below the manufactures recommended settings, this might cure the problem, but do ensure the pump does actually turn off and not just sits there spinning without moving any water - that will shorten the pumps working life quite dramatically. My battery is in good condition showing 13.4 volts after charging and I am also connected to a mains supply.

Caravans

Conversely, if you go off-grid the first time and then you have hook-up the next, a pulsating pump its likely, as the voltage is probably higher than when you were relying on 12V battery power alone (when the charger and/or solar panel are working on our caravan, a charge of 13.7V is often displayed). My immediate thought was that I must have a leak somewhere caused by a frozen pipe over the winter. But I took particular care to drain the system of water using a Floe draindown attachment and also driving the vehicle around with the drain valves open for a while to release any dregs of fluid. With a good pressure switch and using these steps above the pump should work when you want it and stop when you want it to. Now let’s take a look at how to adjust the various types of the most popular pressure switches found in caravans. Whale in-line pressure switch Whale in-line pressure switch might be hidden in pipework The software within the device recognises exactly what the pump is doing at any one time. As the people at Whale also make the pumps they can do this very accurately. Even so, there can be slight differences between individual pumps and so there is a simple ‘one off’ calibration procedureif needed.

Dusty's suggestion of a surge damper may work, but its not actually designed to prevent your specific problem.There's not much to see with Whale's Expanse underfloor heater Combined water and space heaters for caravans As with the in-line pressure switch, the first step is to ensure that the caravan’s water system is completely full and the pump master switch is in the ‘on’ position. Diaphragm pumps are much less susceptible to pressure variations with voltage. For this reason, it is quite common for a pressure switch to be built into the pump as the preferred means of switching. Water heaters for caravans Hot and cold running water is something we take for granted in a caravan – until, perhaps, something goes wrong. Here we look at the technology behind the tap and advise you on how to get the best from your caravan water system. Thanks Derek. Have saved a copy of that exploded view for future reference. Suspect this might not be the last issue I have with the pressure switch.

For the 2012 model year, Coachman chose a more modern unit, the TrumaCombi 4E, for their Amara, Pastiche and VIP ranges. It was the first time a company had specified a Trum aCombi unit for a UK-built caravan. Since then, the cost and weight savings of having a single unit over two separate ones means Bailey, Lunar and Swift fit the Combi fitted to their touring caravans. Most Ultrastore heaters have a water capacity of 10 litres, although a 14-litre version is available. Early models had an element of just 450 watts and took 70 minutes to heat up on electricity only. Over the years Truma upped the power in stages. It now comes with a switchable 850/1300 watt element, reducing the time to 29 minutes, or just 16 minutes if you use gas too. Most caravan pump systems will from time to time exhibit the effect you describe. This is not exceptional and does not represent a fault.Whale's Tiptoe and Flipper pumps were common 30 years ago but are now more likely to be found on boats The second system is the pressure switch system. With this arrangement you have a pressure switch in the water system which senses the water pressure. When you open a tap the pressure in the system will drop, and this drop in pressure on a diaphragm in the pressure switch causes movement of the diaphragm. This movement has the affect of turning the switch 'on' and thus supplying power to the water pump. Conversely when you turn the tap off the pump will continue running for a few seconds which has the effect of building up pressure in the system. This increase in pressure again causes movement of the diaphragm in the pressure switch which has the affect of turning the switch 'off' and thus stopping the pump. If the pump continues to operate after the tap has been turned off then it may simply be due to the pressure switch needing adjustment or there may be a fault with the pressure switch where a component or the whole assembly may need replacing.