Waste holding tank blockage

[andrewbrittain]

We have a problem with the waste tank on our Four Winns Vista 268. It is impossible to empty the tank - either at a waste pump-out station or via the overboard discharge. It feels as though there's some kind of blockage - as when I insert a drain unblocker rod through the discharge hole, I feel a blockage, but there's no way of clearing it - I can only push it back down in to the waste tank, which allows a small bit of waste to be sucked out with the pump - before it then blocks again.

I have no idea how I could possibly access the waste tank to clear the blockage - and I'm unable to find anyone local who specialises in, or knows anything about, fixing such a problem.

 

[kashurst]

have a look on the internet for chemicals that will break down the "solid" bits first

 

[chrisgil]

are you sure it is not a blocked pump? We had a similar issue last year and in the end found a piece of plastic (left over when holes cut in tank for plumbing) lodged in the pump. Pump appeared to work but moved nothing. Plastic removed and everything moved! Good luck

 

[andrewbrittain]

I should have mentioned above that I don't think the blockage is "human waste" because the heads have never been used for that - and I think whatever's causing the blockage is larger and more solid. When I try to use my drain unblocking tool, I can feel something pretty hard in there, which I'm worried chemicals might not be adequate to disintegrate.

 

[Tranona]

Your holding tank should have an inspection hatch in it. If you are sure that there is nothing nasty and liquid in it, open the hatch and see what the blockage is. If it is emptied by gravity then you may be able to clear it from the outlet. If it is a pumped system, then you have no alternative but to makes sure there is nothing liquid in it (pump out from the deck fitting) and disconnect the pipework.

Lots of luck!

 

[fergie_mac66]

if you have a inspec'hatch as a last resort you will have to get a hand bilge pump.A good one will empty the tank using a pipe into the inpection hatch into a caravan waste tank, you can get them for about 10£ rotten job but...