HOW TO UNBLOCK THE WASTE TANK DRAIN (formerly waste tank leaking slightly)

[ejmoore]

The waste tank on our 2018 T6 Cali Ocean seems to dribble slightly all the time out of the discharge pipe. This is noticeable when the tank is filling up & needs emptying, but may occur any time. It's not much, but it makes us look like we've anti-socially left the drain open.

Any thoughts why this might happen, and what can be done to resolve it? Thanks.

 

[WelshGas]

The waste tank on our 2018 T6 Cali Ocean seems to dribble slightly all the time out of the discharge pipe. This is noticeable when the tank is filling up & needs emptying, but may occur any time. It's not much, but it makes us look like we've anti-socially left the drain open.

Any thoughts why this might happen, and what can be done to resolve it? Thanks.

There is an overflow which bypasses the drain tap so the outlet will dribble if the tank is full. Maybe something is caught in the valve stopping it closing fully. Try opening and closing it a few times, vigorously to clear any debris.

 

[ejmoore]

Thank you WG, I'll give that a go.

Also the whole thing is pretty smelly - is there any way of really cleaning the whole system out, other than just flushing it through with clean water, which we do?

 

[ejmoore]

and the flow when it's draining is very feeble - takes forever.

 

[DevillBelgium]

and the flow when it's draining is very feeble - takes forever.

Sounds like the outlet is indeed clogged.
There is a product to clean out the tanks in the shop, you can use this to clean it out.

Fenwicks Waste Pipe & Tank Cleaner - 1 Litre - CampervanBits

Perfect for cleaning grey water system in your campervan or motorhome

vwcaliforniaclub.com

 

[ejmoore]

Sounds like the outlet is indeed clogged.
There is a product to clean out the tanks in the shop, you can use this to clean it out.

Fenwicks Waste Pipe & Tank Cleaner - 1 Litre - CampervanBits

Perfect for cleaning grey water system in your campervan or motorhome

vwcaliforniaclub.com

Thanks - I'll get some, sounds just the thing.

 

[Carabiner]

Hi,

Our brand new 6.1 also has a feeble drain speed. For other 6.1 owners, even when fully emptied, the overhead display still shows fluid in the grey water tank. Is that normal? I'm assuming so.

Thanks, Terry

 

[WelshGas]

Hi,

Our brand new 6.1 also has a feeble drain speed. For other 6.1 owners, even when fully emptied, the overhead display still shows fluid in the grey water tank. Is that normal? I'm assuming so.

Thanks, Terry

Yes.

 

[GrumpyGranddad]

Hi,

Our brand new 6.1 also has a feeble drain speed. For other 6.1 owners, even when fully emptied, the overhead display still shows fluid in the grey water tank. Is that normal? I'm assuming so.

Thanks, Terry

Normal waste tank display.

 

[Stu@rt]

The waste tank indicator is a binary one. It either shows empty or full, no graduation, or scale. I agree that it looks to show something in there, but that is the "empty" state. Once full it shows differently and flashes a msg to tell you to empty it.

 

[andyinluton]

Hi,

Our brand new 6.1 also has a feeble drain speed.

Have you made sure the plug in the sink is out? makes a huge difference.

 

[Carabiner]

Have you made sure the plug in the sink is out? makes a huge difference.

Ah, no, but pretty sure it was out. Will do a more considered test, thanks for the tip.

 

[Hawthorn37]

Thank you WG, I'll give that a go.

Also the whole thing is pretty smelly - is there any way of really cleaning the whole system out, other than just flushing it through with clean water, which we do?

We sanitise the clean tank every couple of months in the summer with Milton (other products are available), then run that tank into the waste tank and let it sit for a while before emptying.

 

[ejmoore]

For the last couple of years, as noted above, we have had problems with the waste tank not draining properly. I tried a number of suggestions - putting Fenwick's tank cleaner down it, hot water, cleaning out the discharge pipe under the van, pumping air up the pipe, etc, all to no avail. However, with a lot more searching on here, I have now found the solution and the tank is emptying properly. Thanks to all the various people who made suggestions. The key to it is understanding the set-up of the tank, and why just putting stuff down the plughole isn't going to cut it. So I'm setting it all out here in case anyone else has the same problem.

Here is the view of the tank from the California technical manual (available somewhere on this forum):

 

[ejmoore]

The waste tank drains out via the (tiny) pipe outlet at the bottom, via a valve that is opened & closed by the red lever in the cupboard next to the fridge. There is also an overflow pipe which comes out of the top of the tank. Our tank was blocked at the main outlet.

To clear the blockage, you need to remove the round panel in the side of the fridge by the open/shut drain valve red lever, so that you can see the overflow pipe (vertical). This overflow pipe needs to be detached at the bottom - there is a jubilee clip to undo. We stopped up the bottom end of the overflow pipe with a bung, and put a finger over the bottom socket end. This is needed so that when you put water or air up the external drainage pipe, it goes into the tank at the bottom rather than via the overflow pipe at the top (where it isn't blocked). The valve should be in the open position.

We then pumped air up the external drainage pipe using the pump from our airbeam awning. Bingo! loud gurgling noise, and (quickly removing the pump), the water then gushed out of the drainage pipe. Result! We then flushed the tank through with a lot of clean water via the sink plughole. In fact I then put some tank cleaner in and some more water, and drove around with it sloshing around on our way to a campsite, where we emptied the tank fully.

Very happy that the tank is now empty and should not be smelly any more.

I've spelled all this out because it took me a hell of a time to find the relevant posts and actually get the thing working properly - understanding the set-up of the tank is key. Thanks to everyone who put useful advice on here.

 

[Hawthorn37]

This is a really useful post. Well done in solving your problem, and documenting it so well. I’m hoping we don’t get this issue, but I know where to search for the solution!

 

[Brian’s Dad]

The waste tank drains out via the (tiny) pipe outlet at the bottom, via a valve that is opened & closed by the red lever in the cupboard next to the fridge. There is also an overflow pipe which comes out of the top of the tank. Our tank was blocked at the main outlet.

To clear the blockage, you need to remove the round panel in the side of the fridge by the open/shut drain valve red lever, so that you can see the overflow pipe (vertical). This overflow pipe needs to be detached at the bottom - there is a jubilee clip to undo. We stopped up the bottom end of the overflow pipe with a bung, and put a finger over the bottom socket end. This is needed so that when you put water or air up the external drainage pipe, it goes into the tank at the bottom rather than via the overflow pipe at the top (where it isn't blocked). The valve should be in the open position.

We then pumped air up the external drainage pipe using the pump from our airbeam awning. Bingo! loud gurgling noise, and (quickly removing the pump), the water then gushed out of the drainage pipe. Result! We then flushed the tank through with a lot of clean water via the sink plughole. In fact I then put some tank cleaner in and some more water, and drove around with it sloshing around on our way to a campsite, where we emptied the tank fully.

Very happy that the tank is now empty and should not be smelly any more.

I've spelled all this out because it took me a hell of a time to find the relevant posts and actually get the thing working properly - understanding the set-up of the tank is key. Thanks to everyone who put useful advice on here.

I’ve had a similar saga recently with a blockage in the waste tank near the drainage tap. In the end I managed to pressurise the tank at the sink plug with a wet/dry vac running in reverse (blowing). As the pressure built I released the valve and pop, out it all came. It seems my vac could blow air in faster the the overflow could allow it to exit. I’ve since had a thorough round of tank cleaning. I tried many other things before this but this worked and in retrospect is a v quick if you’ve got a similar way to pressurise the tank quickly.

 

[Brian’s Dad]

Cleaned the tank with this: Thetford Tank Blaster - Level... https://www.amazon.co.uk/dp/B07D3XYRG5?ref=ppx_pop_mob_ap_share

 

[ejmoore]

I’ve had a similar saga recently with a blockage in the waste tank near the drainage tap. In the end I managed to pressurise the tank at the sink plug with a wet/dry vac running in reverse (blowing). As the pressure built I released the valve and pop, out it all came. It seems my vac could blow air in faster the the overflow could allow it to exit. I’ve since had a thorough round of tank cleaning. I tried many other things before this but this worked and in retrospect is a v quick if you’ve got a similar way to pressurise the tank quickly.

Interesting! I suppose it depends what tools you have to hand. It was realising that we could use a simple air pump (from the awning) rather than a hosepipe that solved our problem, as we live in a flat so external water access is not available.

 

[ejmoore]

I've now changed the title of this thread to make it easier to find in future.

The original problem - dribbling coming from the waste tank - must have been water coming out via the overflow pipe, because we were unable to drain the tank. Anyway, now sorted.

We are always careful not to try not to wash bits down the drain, but we cook and (sometimes) wash up in the van, so it's inevitable. The outlet pipe in the tank is rather too narrow for purpose and easily gets blocked.