Need Help In Unblocking The Drain Of A Waste-Disposal Unit.

[BarnaWill]

Hi all,

Was wondering if someone could help with some advice about unblocking the waste pipe of a waste-disposal unit. It's been blocked for some weeks. I have long thin spiral drain unblocker which didn't work at all. I've recently bought and tried a Karcher pressure washer attachment which similarly did nothing to help.
It's probably the several-years-accumulated waste of the unit, but it's forming a total block somewhere in the down pipe.
A photo of the underneath: www.willshand.com/sink.JPG
The blockage is where the red spot is in the photo - I think!
The Karcher unit doesn't seem to get to the problem, and anyway all the karcher units I saw online seem to spray backwards instead of forwards, which makes no sense to me.
I've tried chemical unblockers, with no success. I've also tried vinegar and bicarb of soda, similarly without success.
It may be that the blockage is not in fact where I think it is, at the 2nd 90 degree angle, but I cannot be sure given that I don't have a camera and can't feel very well with the karcher unit.
Any thoughts? I'm loathe to call in a plumber for something so basic, but I many have to given that the missus is nearing the end of her tether......
Help!

[Buenchico]

Let's try to make that image link 'clickable':
http://www.willshand.com/sink.JPG

[sddsddean]

I would have thought the blockage is more likely to be at the bottom of the U. Can't you disconnect the silver pipe? Looks like the fitting with the blue collar is just a snap fitting (pull the blue collar down and you should be able to wiggle the pipe off...can't see the other end).

[bhg481]

Assuming that the sink and washing machine (?) drain OK, it must be the silver pipe. As sdds says, it's just a push fit, so should be easy to disconnect and check.

[Captain2]

If it's the chrome pipe, where is it expelling the waste to?
(Are we on the continent somewhere?).

[BarnaWill]

Thanks for your comments all. Perhaps I should have explained better; the drain that is blocked is one of the two under the sink, and it's already had everything disconnected from it. The one that's blocked is the one that has an open pipe into the wall.
The other one that has the u bend still on is for the sink + dishwasher.

[BarnaWill]

The two separate drains follow different parallel paths to wherever they go.
The ones that's blocked seems clear until at least the 2nd 90 degree turn at the wall on the right.

[BarnaWill]

We're in Barcelona.
I've removed the waste disposal unit completely already, along with its u bend and connection to its independent drain pipe.

[malagabob]

Can you get to anywhere beyond where the grey pipe, (looks like 42mm Ø) disappears through the wall.

[satprof]

If you can't get something mechanical, like the spiral unblocker, to work, it's there aren't many choices:
1. Stronger chemical unblockers; many of these are now pretty useless in the name of 'health & safety' but caustic soda will shift most organic material blockages. It's just that it's dangerous stuff and you need eye & skin protection and still take a lot of care. (That horizontal entrance to the drain isn't good in this respect. A 90 degree bend plus 30cm of vertical would help.) Caustic soda needs some time to dissolve grease/vegetable matter. It can be problematic if the blockage allows some leakage, as the caustic soda solution keeps leaking away. You need a lot of caustic soda that way. (Be especially careful if you use dry caustic soda pellets. Just adding these to water can cause the water to boil, spraying hot caustic soda solution back up the pipe, almost explosively. If you must use pellets, use very small amounts at a time.)
2. A Karcher pressure solution which seals the entrance to the drain so that the pressure can act on the blockage & not just spray back.
3. Your friendly local 'fontanero'.