Truma pressure switch issue.

Dec 10, 2007
Must admit, rather like Dan Trudgian I’m not a fan of the truma water system particularly the fragile connection and overly stiff pipe. Learning there was a compatible whale pump assembly was too much of a temptation to turn down and hey presto- perfect fit and works perfectly......almost. The issue was there before the change and still remains in that the pump keeps pulsing on and off every 10 seconds or so when the tap is open and running. It suggests to me it’s a pressure switch (truma again)issue, but before I fork out another £50 odd quid could it be some more straightforward that I have missed?
Thanks in advance
Mar 14, 2005
Hello Jim,

If a pump repaetedly cycles as you describe and a pressure switch is fitted, its rare to be the switch its self, but more likley there is a water leak somewhere. The switch is actually doing exactly what it's supposed to do which is to attempt to maintain pressure in the system.

Obviously look for leaking taps, check under the caravan for drips which could be the drain valve not closing properly, check joints for weeps etc. If all seems to be intact, then it could be a non return valve which might be letting water back through the inlet and back to the outside tank. Because its 'internal' you cant se it easily.
Jul 15, 2008
......the OP is reporting a pulsing pump when the tap is open and running so leaks are unlikely to be the cause.
However a restriction in the flow could have this effect.....check tap end inserts for any blockages.
You cold also try the pump with the battery charger off to check if a lower supply voltage cures the problem.
Nov 16, 2015
Just a thought, but if the O, rings, on the Connection to the caravan from the the Auqa roll pump are leaking this could cause the pulsing, but new pump would cancel this thought, maybe a cracked housing or a leaking push fit pipe in the system .

Gafferbills thoughts are better. . :)
May 7, 2012
I would check the valve which can produce that effect. There is a round knob on the top and adjusting this may work, it did for me.


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