Truma SmartSwitch instead of Whale pressure switch

[YorkieF]

Hi All
I've bought a new Truma Smart Switch to replace our whale pressure switch as it's giving us no end of trouble. I've tried adjusting the whale switch as per Lunar and Whale instructions but as soon as the voltage differs from when I set it, (I've got a Sargent solar pane & reg fitted) it either starts to chatter or refuses to turn off the pump. When it chatters, it also turns off the LED ceiling lights. To adjust the pressure switch is a major hassle if the bed is made up or we're having dinner with friends hence my wanting to get rid of the whale switch.



My question is this, does anyone have the Truma Smart Switch fitted to their caravan and how is theirs wired in? The instructions aren't very clear at all. At present with the whale switch fitted, the 12v + goes to the + on the switch then the - from the switch goes to the + on the pump with the pump - going to earth.
I believe that the Truma Smart Switch is fitted to some late coachman models.
Many thanks
Mike

 

[YorkieF]

I eventually sussed it as it's based on a Mid Service switch.

The two wires from the Whale switch fit to the negative terminals on the Truma switch. Then a wire is fitted as a link to one of the terminals at the pump. Which terminal is dependent on whether the circuit is negative or positive switched.
To find out which, touch the + link wire briefly to each of the pump terminals. The correct one is the terminal which makes the pump run faster.

The old whale pressure switch and dog leg that didn't drain out properly.

Truma Smartswitch fitted and also Floë 636 Induratec (black pipe) to get rid of massive part of water system that doesn't drain aft of the kitchen sink. This due to all the bathroom pipes going up to the underneath of the kitchen sink. pipes to get over the wheel arch!