Wast tank heater

I have recently taken delivery of a Warwick XL and am having problems finding out if the wast tank heater blanket is on or not there is a red switch under the offside sofa which looks as though it should light up but does not. Does anyone have any idea how to switch the wast tank on or off and how do I know if it's on or not the instructions in the owners manual are vague to say the least any help would be much appreciated

I have a Warwick Duo and I assume it is the same system. Like you I was confused and the instructions are vague. You have a switch above the sliding door which is for the fresh water heater? Put that on and the waste water heater will then operate using the on off switch under the offside seat. Hope this helps.
Bob

The waste water tank heater will only operate if the fresh water tank heater is on.

As Bobskate says, the switch for the fresh water tank is over the side door in a Warwick Duo (the XL may well be in a different location), so find the fresh water tank heater switch, turn it on and the light in the waste water tank switch will then light up to show that it is working when it is switched on.

Many thanks for that just tried it and it worked. Thanks for your help

Its funny this question has come up, weve had our Xl since September and only the other day while under the rear seat we noticed the red light switch for the waste tank heater was on even with the system all switched off. i assumed everything went off when the system was off.

Mine is off when the tank heater switch is off on the control panel above the sliding door as spospe and bob skate say above. Even when the switch is on I can still switch the red button off inthe user manual it says the heater should not be switched on if there is no water in the tank.

I realise it should,nt be on without water in the tank, it must have got knocked on somehow but surely it should,nt be live with the system off.

On the subject of tank heaters, when I bought my Sussex Duo, the salesman( Marquis) said that it has a winter package including a Fresh water tank heater. Can anySussex Duo guys out there confirm? If so, is it switched ? 
Thanks