I'd appreciate some practical advice on how to clear a blockage in the
outlet tube from our Bosch dishwasher please.

Evil smelling water remains after a wash. The filters and hole below them
seem clear. As far as I can make out, waste is pumped out from below into
a flexible hose that then comes up through the adjacent cupboard and
connects to the side of the U-tube underneath the kitchen sink, as shown
in this photo:

http://dl.dropbox.com/u/4019461/DishwasherDrain.jpg

The sink is draining fine, so it seems to me that the blockage must be
somewhere in this tube. Without MAJOR hassle, or calling in a plumber,
disconnecting it at the dishwasher itself is not an option. Which of the
connections is best to remove: A, B or C? More to the point, what should I
do once I've got access to that end?

Should I connect my garden hose somehow and force mains-pressured water
down it?

How about pouring drain-cleaning stuff (caustic soda?) in?

Any advice would be much appreciated please.

--
Terry, East Grinstead, UK

Terry Pinnell wrote:
I'd appreciate some practical advice on how to clear a blockage in the
outlet tube from our Bosch dishwasher please.

Evil smelling water remains after a wash. The filters and hole below them
seem clear. As far as I can make out, waste is pumped out from below into
a flexible hose that then comes up through the adjacent cupboard and
connects to the side of the U-tube underneath the kitchen sink, as shown
in this photo:

http://dl.dropbox.com/u/4019461/DishwasherDrain.jpg

The sink is draining fine, so it seems to me that the blockage must be
somewhere in this tube. Without MAJOR hassle, or calling in a plumber,
disconnecting it at the dishwasher itself is not an option. Which of the
connections is best to remove: A, B or C? More to the point, what should I
do once I've got access to that end?

Should I connect my garden hose somehow and force mains-pressured water
down it?

How about pouring drain-cleaning stuff (caustic soda?) in?

Any advice would be much appreciated please.

You will have to make disconnecting at the dishwasher end into an
option! remove hose completely and sort it out properly.

On Feb 4, 8:45*am, Bob Minchin
wrote:
Terry Pinnell wrote:
I'd *appreciate some practical advice on how to clear a blockage in the
outlet tube from our Bosch dishwasher please.

Evil smelling water remains after a wash. The filters and hole below them
seem clear. As far as I can make out, waste is pumped out from below into
a flexible hose that then comes up through the adjacent cupboard and
connects to the side of the U-tube underneath the kitchen sink, as shown
in this photo:

http://dl.dropbox.com/u/4019461/DishwasherDrain.jpg

The sink is draining fine, so it seems to me that the blockage must be
somewhere in this tube. Without MAJOR hassle, or calling in a plumber,
disconnecting it at the dishwasher itself is not an option. Which of the
connections is best to remove: A, B or C? More to the point, what should I
do once I've got access to that end?

Should I connect my garden hose somehow and force mains-pressured water
down it?

How about pouring drain-cleaning stuff (caustic soda?) in?

Any advice would be much appreciated please.

You will have to make disconnecting at the dishwasher end into an
option! remove hose completely and sort it out properly.

Its not hard to do, just tip the machine over and undo the clip.


NT

On Fri, 04 Feb 2011 07:49:23 +0000, Terry Pinnell wrote:

I'd appreciate some practical advice on how to clear a blockage in the
outlet tube from our Bosch dishwasher please.

Evil smelling water remains after a wash. The filters and hole below
them seem clear. As far as I can make out, waste is pumped out from
below into a flexible hose that then comes up through the adjacent
cupboard and connects to the side of the U-tube underneath the kitchen
sink, as shown in this photo:

http://dl.dropbox.com/u/4019461/DishwasherDrain.jpg

The sink is draining fine, so it seems to me that the blockage must be
somewhere in this tube. Without MAJOR hassle, or calling in a plumber,
disconnecting it at the dishwasher itself is not an option. Which of the
connections is best to remove: A, B or C? More to the point, what should
I do once I've got access to that end?

You can't, really. It isn't hard to do it at the other end, and wouldn't
be a plumber's job anyway. Just take the side off the dishwasher. There
may be a plastic clip (a sort of 'channel') that you have to prise off;
it may break a lug or two (mine did) but there's an obvious place for a
small bolt to be inserted when reassembling. The actual connection, once
inside, is trivial.
--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor

On Fri, 04 Feb 2011 07:49:23 +0000, Terry Pinnell
wrote:

Which of the
connections is best to remove: A, B or C? More to the point, what should I
do once I've got access to that end?

You may be lucky and the blockage is at B. If you remove at C and A
and visually inspect the tube it may be there. Other common cause is
thin bones getting past the filter and jamming the drain pump
impeller. The drain pump has a very low starting power so can easily
jam. Usually there is a fan on the other end which you can turn by
hand once you tip the dishwasher up so you can check it.

Peter Parry wrote:

On Fri, 04 Feb 2011 07:49:23 +0000, Terry Pinnell
wrote:

Which of the
connections is best to remove: A, B or C? More to the point, what should I
do once I've got access to that end?

You may be lucky and the blockage is at B. If you remove at C and A
and visually inspect the tube it may be there. Other common cause is
thin bones getting past the filter and jamming the drain pump
impeller. The drain pump has a very low starting power so can easily
jam. Usually there is a fan on the other end which you can turn by
hand once you tip the dishwasher up so you can check it.

Bob (Eager), Peter:

Thanks both.

Further close examination appears to indicate that it's not a blockage in
the dishwasher drain tube after all.

I hope I'm right, because I'm not at all confident about being able to
slide out the dishwasher itself. When we had wood panel flooring
installed, an 'edging strip' obstructs that. If it wasn't already obvious,
I'm posting here as an inexperienced DIYer.

But I'll describe what I see as best I can and would appreciate
confirmation of that please.

http://dl.dropbox.com/u/4019461/SinkDrainBlockage-1.jpg

What I'm trying to show is that the water that has drained from the sink
(and dishwasher, and draining board) appears gradually to rise. So that
eventually it reaches the level of the dishwasher outlet hose.

Yesterday I used a 'sink plunger' on the drain/filter hole of the
dishwasher and put it through a couple of washing cycles while empty. That
appeared to clear it fully. IOW, there was no water obvious at the base of
the washing compartment.

But this morning there was. A lot, and foul smelling. That's what prompted
me to closely examine the sink itself. After yet another pre-wash cycle I
watched the water pumping out of its drain hose into a point a couple of
inches above the top of the U-tube. After that had drained away, the water
surface appeared to be where I would expect, i.e. at the top of the
U-tube. But after 5 minutes or so it had risen as I described. So it would
now be flowing back under gravity into the dishwasher.

I'm right, it's a complete mystery to me how this could happen! After the
U-tube, the pipe goes drops gradually to a drain outside the house. As it
happens (an unrelated issue) the vertical section of that pipe outside the
house a few inches above the drain recently got broken, and I haven't yet
fixed it, so I can see the sink water gushing out.

--
Terry, East Grinstead, UK

On Feb 6, 12:13*pm, Terry Pinnell wrote:
Peter Parry wrote:
On Fri, 04 Feb 2011 07:49:23 +0000, Terry Pinnell
wrote:

Which of the
connections is best to remove: A, B or C? More to the point, what should I
do once I've got access to that end?

You may be lucky and the blockage is at B. *If you remove at C and A
and visually inspect the tube it may be there. *Other common cause is
thin bones getting past the filter and jamming the drain pump
impeller. *The drain pump has a very low starting power so can easily
jam. *Usually there is a fan on the other end which you can turn by
hand once you tip the dishwasher up so you can check it.

Bob (Eager), Peter:

Thanks both.

Further close examination appears to indicate that it's not a blockage in
the dishwasher drain tube after all.

I hope I'm right, because I'm not at all confident about being able to
slide out the dishwasher itself. When we had wood panel flooring
installed, an 'edging strip' obstructs that. If it wasn't already obvious,
I'm posting here as an inexperienced DIYer.

But I'll describe what I see as best I can and would appreciate
confirmation of that please.

http://dl.dropbox.com/u/4019461/SinkDrainBlockage-1.jpg

What I'm trying to show is that the water that has drained from the sink
(and dishwasher, and draining board) appears gradually to rise. So that
eventually it reaches the level of the dishwasher outlet hose.

Yesterday I used a 'sink plunger' on the drain/filter hole of the
dishwasher and put it through a couple of washing cycles while empty. That
appeared to clear it fully. IOW, there was no water obvious at the base of
the washing compartment.

But this morning there was. A lot, and foul smelling. That's what prompted
me to closely examine the sink itself. After yet another pre-wash cycle I
watched the water pumping out of its drain hose into a point a couple of
inches above the top of the U-tube. After that had drained away, the water
surface appeared to be where I would expect, i.e. at the top of the
U-tube. But after 5 minutes or so it had risen as I described. So it would
now be flowing back under gravity into the dishwasher.

I'm right, it's a complete mystery to me how this could happen! After the
U-tube, the pipe goes drops gradually to a drain outside the house. As it
happens (an unrelated issue) the vertical section of that pipe outside the
house *a few inches above the drain recently got broken, and I haven't yet
fixed it, so I can see the sink water gushing out.

Sounds like a partial block further down the system, somewhere after
another appliance discharges into the pipework. A chemical cleaner may
help clear it.
http://wiki.diyfaq.org.uk/index.php?...nblock_a_Drain

If there's enough slack in the dishwasher drain pipe, just tying it
higher up would prevent this backflow.


NT

Tabby wrote:

On Feb 6, 12:13*pm, Terry Pinnell wrote:
Peter Parry wrote:
On Fri, 04 Feb 2011 07:49:23 +0000, Terry Pinnell
wrote:

Which of the
connections is best to remove: A, B or C? More to the point, what should I
do once I've got access to that end?

You may be lucky and the blockage is at B. *If you remove at C and A
and visually inspect the tube it may be there. *Other common cause is
thin bones getting past the filter and jamming the drain pump
impeller. *The drain pump has a very low starting power so can easily
jam. *Usually there is a fan on the other end which you can turn by
hand once you tip the dishwasher up so you can check it.

Bob (Eager), Peter:

Thanks both.

Further close examination appears to indicate that it's not a blockage in
the dishwasher drain tube after all.

I hope I'm right, because I'm not at all confident about being able to
slide out the dishwasher itself. When we had wood panel flooring
installed, an 'edging strip' obstructs that. If it wasn't already obvious,
I'm posting here as an inexperienced DIYer.

But I'll describe what I see as best I can and would appreciate
confirmation of that please.

http://dl.dropbox.com/u/4019461/SinkDrainBlockage-1.jpg

What I'm trying to show is that the water that has drained from the sink
(and dishwasher, and draining board) appears gradually to rise. So that
eventually it reaches the level of the dishwasher outlet hose.

Yesterday I used a 'sink plunger' on the drain/filter hole of the
dishwasher and put it through a couple of washing cycles while empty. That
appeared to clear it fully. IOW, there was no water obvious at the base of
the washing compartment.

But this morning there was. A lot, and foul smelling. That's what prompted
me to closely examine the sink itself. After yet another pre-wash cycle I
watched the water pumping out of its drain hose into a point a couple of
inches above the top of the U-tube. After that had drained away, the water
surface appeared to be where I would expect, i.e. at the top of the
U-tube. But after 5 minutes or so it had risen as I described. So it would
now be flowing back under gravity into the dishwasher.

I'm right, it's a complete mystery to me how this could happen! After the
U-tube, the pipe goes drops gradually to a drain outside the house. As it
happens (an unrelated issue) the vertical section of that pipe outside the
house *a few inches above the drain recently got broken, and I haven't yet
fixed it, so I can see the sink water gushing out.

Sounds like a partial block further down the system, somewhere after
another appliance discharges into the pipework. A chemical cleaner may
help clear it.
http://wiki.diyfaq.org.uk/index.php?...nblock_a_Drain

If there's enough slack in the dishwasher drain pipe, just tying it
higher up would prevent this backflow.

Thanks Tabby, much appreciate the fast reply. Your last point is a
brilliant idea, despite its simplicity! There is in fact plenty of slack,
so I've raised the hose so that its height is now an inch or two above the
entrance into the sink drain.

Would you anticipate the pump having any difficulty with that slightly
greater height?

Re the chemicals, I did in fact give it a couple of capfuls of sink
cleaner this morning. Maybe that's contributed to the current status,
which is: hot wash now finished, no water obvious in dishwasher, water
surface in sink drain where it should be (inches below the 'flow-back'
level).

That leaves the mystery of the rising level! Logic compelled me to think
along same lines you described. But I can't think *what* other appliance
could drain into that section. In a moment of madness I even went upstairs
and ran sink and bath taps, but of course their waste doesn't emerge in
that pipe. After the U-Tube, the plastic pipe just runs at a slight
downward angle across the cupboard, makes a small dog-leg into the
inaccessible corner unit, and then emerges from the outside wall 3 feet
away.

BTW, I'm in the dog house now. I'd unscrewed the sink drain cover to get a
better view down it. Then I decided I'd stick the rubber plug in and fill
the sink in order to give it a thorough flushing out. Whereupon the
cupboards and floor were immediately soaked before I got to the tap!
Needless to say, my wife wasn't impressed!

--
Terry, East Grinstead, UK

In article 9392c28c-8507-460c-b32a-464ca6948628
@n18g2000vbq.googlegroups.com, says...
If there's enough slack in the dishwasher drain pipe, just tying it
higher up would prevent this backflow.


+1

Lift the incoming hose to make more of a hump before the connection to
the drain.

--
Skipweasel - never knowingly understood.

On 06/02/2011 12:56, Terry Pinnell wrote:

Would you anticipate the pump having any difficulty with that slightly
greater height?

Shouldn't be a problem. I'd raise it to be as high as possible, ours is
only an inch or two below the underside of the worktop.

--
Mike Clarke

Skipweasel wrote:

In article 9392c28c-8507-460c-b32a-464ca6948628
, says...
If there's enough slack in the dishwasher drain pipe, just tying it
higher up would prevent this backflow.


+1

Lift the incoming hose to make more of a hump before the connection to
the drain.

Thanks both, done.

I'm still pondering over the mysterious rising level, but several hours on
and haven't seen it repeated, so I'm optimistic! ;-)


--
Terry, East Grinstead, UK

On Feb 6, 12:56*pm, Terry Pinnell wrote:
Tabby wrote:
On Feb 6, 12:13 pm, Terry Pinnell wrote:
Peter Parry wrote:
On Fri, 04 Feb 2011 07:49:23 +0000, Terry Pinnell
wrote:

Which of the
connections is best to remove: A, B or C? More to the point, what should I
do once I've got access to that end?

You may be lucky and the blockage is at B. If you remove at C and A
and visually inspect the tube it may be there. Other common cause is
thin bones getting past the filter and jamming the drain pump
impeller. The drain pump has a very low starting power so can easily
jam. Usually there is a fan on the other end which you can turn by
hand once you tip the dishwasher up so you can check it.

Bob (Eager), Peter:

Thanks both.

Further close examination appears to indicate that it's not a blockage in
the dishwasher drain tube after all.

I hope I'm right, because I'm not at all confident about being able to
slide out the dishwasher itself. When we had wood panel flooring
installed, an 'edging strip' obstructs that. If it wasn't already obvious,
I'm posting here as an inexperienced DIYer.

But I'll describe what I see as best I can and would appreciate
confirmation of that please.

http://dl.dropbox.com/u/4019461/SinkDrainBlockage-1.jpg

What I'm trying to show is that the water that has drained from the sink
(and dishwasher, and draining board) appears gradually to rise. So that
eventually it reaches the level of the dishwasher outlet hose.

Yesterday I used a 'sink plunger' on the drain/filter hole of the
dishwasher and put it through a couple of washing cycles while empty. That
appeared to clear it fully. IOW, there was no water obvious at the base of
the washing compartment.

But this morning there was. A lot, and foul smelling. That's what prompted
me to closely examine the sink itself. After yet another pre-wash cycle I
watched the water pumping out of its drain hose into a point a couple of
inches above the top of the U-tube. After that had drained away, the water
surface appeared to be where I would expect, i.e. at the top of the
U-tube. But after 5 minutes or so it had risen as I described. So it would
now be flowing back under gravity into the dishwasher.

I'm right, it's a complete mystery to me how this could happen! After the
U-tube, the pipe goes drops gradually to a drain outside the house. As it
happens (an unrelated issue) the vertical section of that pipe outside the
house a few inches above the drain recently got broken, and I haven't yet
fixed it, so I can see the sink water gushing out.

Sounds like a partial block further down the system, somewhere after
another appliance discharges into the pipework. A chemical cleaner may
help clear it.
http://wiki.diyfaq.org.uk/index.php?...nblock_a_Drain

If there's enough slack in the dishwasher drain pipe, just tying it
higher up would prevent this backflow.

Thanks Tabby, much appreciate the fast reply. Your last point is a
brilliant idea, despite its simplicity! There is in fact plenty of slack,
so I've raised the hose so that its height is now an inch or two above the
entrance into the sink drain.

I'm not sure how much difference an inch would make, its not much.

Would you anticipate the pump having any difficulty with that slightly
greater height?

no

If the drain cleaner has helped, I'd repeat it a few times to help
clear it more.


NT