Dishwasher fit - too much pipework?

Joy_12345

Joy_12345 said:

Thank you. Before I remove the vertical standpipe, could there have been a good reason for it, rather than the waste going straight into the T pipe? e.g. Might it have been tall to prevent other waste water entering the dishwasher from elsewhere? And if so, is there an alternative workaround?

Also, would I remove the black and grey bits too, or is there a reason for those?

Several reasons: 

• the U/P trap
• with a standpipe the hose could be loosely inserted into it, without it the connection has to be tight and sealed

You can possibly create something similar to a trap by fixing the hose to the wall.

How far away is the sink? I see up to 4m extension hose kits available.

Thanks. I now know more about plumbing than I did yesterday, and won't be removing any U/P traps! The sink is under 2m away.

WIAWSNB

Joy_12345 said:

Thanks. I now know more about plumbing than I did yesterday, and won't be removing any U/P traps! The sink is under 2m away.

It certainly looks poorly designed, with the location of the vertical pipe seemingly reducing the available depth by a good further 2-3".

You have the three options

Well, 4 - have the DW sticking out.

Um, five... do away with the DW altogether.

Possibly six - get a slimline DW that slips down the LH side. 

IF moving the vertical pipe to flat against the back wall - which will mean it won't stick out any further than the horizontal pipe - will do the job, ie allow the DW to move in far enough for you, then that is unquestionable the most obvious solution and easiest solution.

Failing that, I think I'd be looking at a hose extension, and drilling small - 1" - holes at the back/tops of the adjacent unit sides where it just won't be seen, and threading that hose through to the sink base. The hose end then just pushes (and clips for security) on to a hose spigot, which may need to be added - easy. 

The other option of moving the vertical pipe to an adjacent unit will involve too much plumbing and butchery.

Joy_12345

The vertical pipe is the standard way to take a dishwasher or washing machine waste.
The outlet hose from the appliance sits loosely inside that pipe, and allows air to be drawn in around it along with the ejected water - this prevents the DW/WM from being continually 'sucked' empty by the water flow. The air gap is necessary.
The alternative, which is why you have been asked whether there's a sink adjacent to that space, is to take the DW hose directly to the sink waste, to a connector immediately below the sinktop.
You have three options, afaIcs;
1) adjust that vertical pipe as described by Alan above. Do you understand what he means? In essence, that vertical pipe is moved from the unit side to the back wall, so saving you its thickness.
2) provided the sinktop isn't too far away, it should be possible to completely remove that vertical pipe and U-bend, and cap it off at the 'tee'. The DW outlet hose can then be extended with a kit, passed through a small hole in the unit side at the back, taken to the sink unit, and connected via an adaptor directly to the sink's plumbing. So, where is the sinktop?
3) the vertical pipe and U-bend can be moved to the adjacent unit and mounted there instead. The white horizontal waste pipe clearly runs behind both side units, so you'd have a choice! Ie, the existing 'tee' is either capped or replaced by a straight connector, and a new tee and the vertical pipe fitted at the back of one of the side units. The hose is then taken via a small hole through the side at the back to the new vertical pipe location.
Option 1 is by far the easiest, provided it gives you the required depth?

Thank you so much for explaining all this!

1) Yes - understood. When I twist it around, there may not be enough height on the 'trunk' of the tee (and the first part of the black pipe that connects into it) to allow the U to sit on top of the horizontal waste pipe, unless I can buy a taller tee? If that does work but the vertical pipe hits the work surface above, can a small amount be cut off the vertical pipe from the top? Is there a minimum height? The narrower horizontal pipes higher up will also prevent it from sitting flush to the wall, but it would still save some space. Whichever way, I will give it a go - is it safe to undo the tee providing I don't have water running? 

2) The sink pipework is less than 2m away from the furthest point in the hole.

3) Understood - and I guess option 2 is preferable (less work) given the sink is close enough?

grumpy_codger

WIAWSNB said:

Joy_12345 said:

Thanks. I now know more about plumbing than I did yesterday, and won't be removing any U/P traps! The sink is under 2m away.

...

Failing that, I think I'd be looking at a hose extension, and drilling small - 1" - holes at the back/tops of the adjacent unit sides where it just won't be seen, and threading that hose through to the sink base. The hose end then just pushes (and clips for security) on to a hose spigot, which may need to be added - easy. 

The other option of moving the vertical pipe to an adjacent unit will involve too much plumbing and butchery.

If the cabinets plinth is removable (most likely it is), the hose can go under the cabinets.

WIAWSNB

grumpy_codger said:

WIAWSNB said:

Joy_12345 said:

Thanks. I now know more about plumbing than I did yesterday, and won't be removing any U/P traps! The sink is under 2m away.

...

Failing that, I think I'd be looking at a hose extension, and drilling small - 1" - holes at the back/tops of the adjacent unit sides where it just won't be seen, and threading that hose through to the sink base. The hose end then just pushes (and clips for security) on to a hose spigot, which may need to be added - easy. 

The other option of moving the vertical pipe to an adjacent unit will involve too much plumbing and butchery.

If the cabinets plinth is removable (most likely it is), the hose can go under the cabinets.

Yes, but it would be left with standing water each time. I don't know if that's an issue? 

WIAWSNB

Joy_12345 said:

Thank you so much for explaining all this!

1) Yes - understood. When I twist it around, there may not be enough height on the 'trunk' of the tee (and the first part of the black pipe that connects into it) to allow the U to sit on top of the horizontal waste pipe, unless I can buy a taller tee? If that does work but the vertical pipe hits the work surface above, can a small amount be cut off the vertical pipe from the top? Is there a minimum height? The narrower horizontal pipes higher up will also prevent it from sitting flush to the wall, but it would still save some space. Whichever way, I will give it a go - is it safe to undo the tee providing I don't have water running? 

2) The sink pipework is less than 2m away from the furthest point in the hole.

3) Understood - and I guess option 2 is preferable (less work) given the sink is close enough?

BiB - you are absolutely right - the black elbow-to-tee will need an extension. How annoying. 

I have looked for an 'extension' fitting - one with a socket at one end (that'll take the black elbow) and plain pipe at t'other (to go into the Tee's 'compression' fitting) - but now't. Unbelievable.  

And, yes, the raised height will mean the vertical pipe top will be too high, not just for the worktop, but also for the recommended spec for DWs and WMs, which I understand is around 75cm off the ground (the hose loops a bit over this). So, yes, you'd trim the top piece so's it's this height. 

Can you safely undo that tee? Yes - it should be empty... Ie, it should have a 'fall' towards the outside drain, and not have any standing water in it. Obviously have a container under it to catch water chust in case.

What I would do in that situation is first confirm whether repositioning that vertical pipe and U-bend to the back wall will do the job, allowing for the fact the water pipes behind it will keep it off the wall an inch or so. 

So, get the answer to that! 

If it is good enough, then I'd undo the black elbow from the tee - you slacken that serrated collar on the tee, and pull the elbow out with a rocking motion. Remove the vert pipe and bits. 

Now test the vertical pipe for size for fitting straight into the tee. Is it the correct size? If 'yes', then you can use that old vert pipe for your extension piece :-)

Slacken the two other collars on the tee, and rotate it until the tee is upwards. Retighten. 

I bought and fitted one of these a couple of weeks ago: https://www.screwfix.com/p/floplast-washing-machine-trap-white-40mm/18640 They are very decent quality, and cracking value. It also has two clips... I suggest you use this new WM waste and a new compression elbow and the old vert waste pipe to make up your new assembly. 

Ie, lose the old black elbow and the strange-coloured connecting pipe. You will instead be using the new WM waste and U-bend, a new compression elbow, and the old waste pipe cut to suitable lengths to join them all - between the U and the elbow, and the elbow and the tee. 

Does that make sense? 

Give all the compression parts a smear with washing up liquid to make it smooth to assemble.  

WIAWSNB

This might also be of use - this is the one I did just a week ago. The wall is tiled, and I didn't want to drill into it, so I cut a couple of timber battens - around 1" thick - and StixAll'd them to the wall instead. 

This would give you an easier task - no drilling into solid wall - but also the clearance needed to avoid the copper pipes. 

(No screws came with the WM waste, so you'd need a couple extra - use the ones on the existing clip.) 

jennifernil

Our dish washer is around a corner from the sink, there is a 900 x 900 mm corner unit, a 400mm wide tray space and about 500 mm of under sink cupboard for its waste pipe to traverse, and an extension waste hose is used, it runs behind the units at a height of about 450mm.  It drains directly into the sink plumbing using the type of fitting previously described.  Works fine, no problems.

casper_gutman

jennifernil said:

Our dish washer is around a corner from the sink, there is a 900 x 900 mm corner unit, a 400mm wide tray space and about 500 mm of under sink cupboard for its waste pipe to traverse, and an extension waste hose is used, it runs behind the units at a height of about 450mm.  It drains directly into the sink plumbing using the type of fitting previously described.  Works fine, no problems.

Our setup also works fine and is similar, except that instead of the 400mm tray space there's a slimline dishwasher.* 

*Yes, another one. You want to make something of it?

molerat

casper_gutman said:

jennifernil said:

Our dish washer is around a corner from the sink, there is a 900 x 900 mm corner unit, a 400mm wide tray space and about 500 mm of under sink cupboard for its waste pipe to traverse, and an extension waste hose is used, it runs behind the units at a height of about 450mm.  It drains directly into the sink plumbing using the type of fitting previously described.  Works fine, no problems.

Our setup also works fine and is similar, except that instead of the 400mm tray space there's a slimline dishwasher.* 

*Yes, another one. You want to make something of it?

Did similar for my son.  Drilled through a 1m double unit, a full corner unit then behind washing machine and into the plumbing under the sink so a good 2.5m.  The units were not solid backed so clipped the pipes to the bar on top of the board back.