Water tank issue

[Willshake]

I’m a newbie 680 owner with a water tank problem!
Having filled the water tank full ( water spilling out of filler neck) I traveled to first site. It was a cold evening 3c . I went out for a couple of hours and on returning found a completely discharged tank.
Is this the safety system kicking in and if so can it be avoided?

 

[Mr T]

I’m a newbie 680 owner with a water tank problem!
Having filled the water tank full ( water spilling out of filler neck) I traveled to first site. It was a cold evening 3c . I went out for a couple of hours and on returning found a completely discharged tank.
Is this the safety system kicking in and if so can it be avoided?

Welcome. Yes the Truma will dump the water if the temp falls below 3degrees ish.
You’ll need to get the interior warm and reset the trip via the flap on the side of the rear bench seat.
Ideally you would warm the vehicle up using the electric (or gas/diesel) heating before filling the water tank. This is standard Truma behaviour and not unique to the Grand.
Alternatively get to where you’re going and chances are the cabin is warm. By them from driving and having some heat, then fill your water tank up. However if you let the inside temp drop down it will dump the water again.