Altering the run of the discharge from the waste tank.

[Wilson]

Hi. We own a Compass Castaway RG 2005 model and wish to alter the run of the discharge from the waste tank. At the moment, the waste discharges from the tank through a grey ribbed convoluted pipe and a rather small grey tank drain tap on the offside of the van just behind the rear wheel. As the tap is hard to reach and in any event becomes very dirty from road mud, we would like to completely replace the original waste pipe and tap and route it so that it discharges from the rear of the van. Having looked under the van, we think this could be easily achieved however; we cannot work out what size of pipe we should use. How do you know what size of new pipe required to connect to the waste tank outlet? The outside diameter of the original pipe is 35mm but is that the size of pipe we need or should we measure the diameter from the inside of the pipe? We cannot of course measure the inside without disconnecting the waste pipe from the tank itself and we would prefer not to do this, unless we have too of course, before we are ready to do the whole job. On the question of pipe size C.A.K. Tanks seem to sell supaflex hose which could be used but this comes in a number of sizes (20mm, 25mm, 38mm, or 40mm) none of which seem to be close to the size we have at the moment! The alternative is of course is to use domestic PVCu waste pipe from a plumbing merchant but again what size, there are so many! In any event, which is the best type of pipe to use? It should be a straight run from the tank to the rear of the van. Any advice would be much appreciated please.

[Brian Kirby]

Wilson

I think the only advice can be to disconnect the existing flexible and measure the outlet spigot.  Until you bite the bullet and do this, all will be speculative, and any materials you buy in advance liable to prove useless.  While underneath you could also check what the waste tank is made from.  The simple answer is to use the largest smooth bore pipe that will fit, rigid domestic waste will be fine, if you can get a size to couple to the spigot.  Whatever you use will need to be strongly supported.  It seems the drain cock is to be at the end of the waste pipe.  This means the pipe will run full, so the supports must be capable of taking the weight of the full pipe and resisting the bangs and vibrations of the moving vehicle.  Once you've worked out what you've got, then talk to CAK about what can be used.

However, where is your spare wheel?  If underneath at the rear, remember to allow for dropping the cradle when siting the pipe run.  You won't want to add sawing off your waste pipe to the pleasures of changing a wheel on a on a dark, wet, night!

[Rayjsj]

Wilson,

I did this job on my Autosleeper Talisman, used CAK superflex hose, (which is convoluted on the outside but smooth inside) mine was 25mm,3/4" Supadrain Tap,3/4"x 1" hose barb Straight Fitting (could have an elbow here if you like) and 3 metres of 25mm Superflex Black hose.

I used about a metre from Tank to rear of van. the rest I keep to Plug onto the 'barb' if I park too far away from the Drain point (which I often do !) works a treat ! and drains in couple of minutes instead of 10 + .

You DO need to measure the outlet from the tank though, if the outside of the present convoluted is 35mm i would think 25mm would be your size too. But..... always check. By the way the whole lot only cost £24

including a s/steel jubilee clip and postage. CAK are very helpful on the phone too. good luck RayJ.

[Wilson]

Hi

 

Just a short note to thank both Brian and Raymond for their contribution and advice. I will be checking under the van shortly, once the rain stops!?

 

Wilson