Dish washer / sink waste questions ..

[T i m]

Hi All,

A mate rang Monday asking for a hand with a 'plumbing problem'.

I turns out the dishwasher outlet pipe had overflowed and screwed their laminate kitchen flooring (can't see what's wrong with Lino meself but hey ..).

Anyway, it seems the waste starts from the sink in 1 1/2" plastic and a 90 deg elbow on the outside wall, passes (sloping downwards) by the diswasher outlet with a 'T' and continues to a jogle in the wall (another 90 deg elbow) round the outside wall (90 deg) and into the drain.

This seems to be old grey Hunter stuff that *looks* like it was once 'push fit' but also looks pretty old and brittle?

On the inside and under the worktop is a shortish upstand (when I've fitted them at home in the past I've made them as high as possible) and straight through the wall with a 90 deg elbow (no trap)?

I have seen 'combined' fittings where one appliance waste hooks over the top and the other conncts to a serrated fitting. Is there a single fitting like this that would be sealed (or is it supposed to be a 'nuisance'). You could fit a 'Gurgle Valve' (or whatever they are called) to prevent airlocks?

There are also no rodding eyes or any bit's that look like they would easily come apart for cleaning?

So, what's the 'bottom line' on working on this sort of stuff these days please?

Assuming he's allowed to sort this out himself (with guidance from the learned panel of course) what sort of things should he (we) look out for?

I believe it would be good to fit a rodding eye to any runs that might need access later but how would you sort the length of pipe that goes straight through the wall and picks up the passing run? Maybe the passing pipe should be lowered so that the dishwasher pipe joins it from above so it can have it's own rodding eye where the pipe exits the wall (now vertically)?

Do they do 'push fit' in grey or would it have to be the glued stuff (is there a 'rule' re what's used now / outside Someone else has plumbed in a washing machine and the external stuff is in white (I prefer black or grey).

Is B&Q (handy for him) as good a place as any for him to get the components?

All the best and thanks for your time (as always) ;-)

T i m

[Andy Hall]

That'll teach him not to use unsuitable materials in a kitchen ;-)

I wonder if it's too long........

You can get a type of sink waste that has spigots to take appliance hoses joining below the sink and above the trap. Franke make them among others.

Could a slightly longer waste hose be fitted to the dishwasher to run to a waste like this.

The other point is why did the waste overflow? Was it blocked or was the pipe too small and long after the place where the DW waste joins, or perhaps the slope inadequate? Replacing it all with 50mm would be helpful.

You could easily incorporate that by using a tee with a 135 degree branch and putting a removable blanking fitting on it.

If you use a removable trap there should not be an issue anyway.

Push fit stuff is fairly crappy. Solvent weld is much better and generally cheaper. B&Q sell Marley IIRC and the solvent is available at the registers.

The important thing is to wait the prescribed time after assembly before running water through it. Tell him not to get the solvent in his eyes.

While you're at it you might as well tell him to sling out the flooring.... it's not suitable for kitchen use - in fact I can't think of any domestic situation where laminate flooring is appropriate.

.andy

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[T i m]

Well indeed .. but to be fair it's sort of a kichen diner thing .. ?

Is there an occasion where you would sort of 'plumb' (rather than lodge / hook) a machine outlet into a waste system? What I'm suggesting here is that *if* the waste should block it couldn't overflow (just wouldn't pumpout properly etc). You could use a spigot type with the top if the upstand part blanked off (with a breather valve?).

The washing machine comes in from a different direction and has it's own waste plumbing so the diswasher has the waste pretty much all to itself (with the less used sink).

Well it *has* been ok for the probably 3 years they have lived there so I can only assume a blockage, probably in the bottom of the internal riser pipe / the bit that goes out through the wall?

Replacing it all with 50mm would be

Funny you should mention that Andy as he mentioned there was some 'issue' when he / another did the washing machine waste re "the pipes are different sizes these days aren't they"? Now I know 1/2" copper became 15mm and 3/4 became 22mm (were there adaptors?) so has the same thing happened with 1 1/4" amd 1 1/2" wastes, or are 32 / 40 mm driect (interchangeable) equivs?

Oh so that's one in and sort of straight T with a mutant extra branch, all on the same plane?

Fair enough. It's pretty tight for space in there so is it acceptable to chase the wall out around the 'nut' that tightens the waste into the exit part of the trap that goes through the wall (so it fit's as far back as possible but you can still get the plastic nut / washer / rubber gland undone (to remove the through the wall pipe)?

Push fit stuff is fairly crappy. Solvent weld is much better and

Ok, I've got some solvent cement (for other reasons ) so he just needs the pipe / parts.

Ok .. knowing his attention to detail (or lack of) I think I know who might be doing the tricky bits ;-)

You could be right Andy .. we have resisted here ..

All the best and thanks again ..

T i m

[Andy Hall]

Still no excuse..... ;-)

I can see what you are saying. I've never seen the breather valve idea used for this though. It would only marginally help, because if the pipe is blocked or partly blocked below the tee then waste water from the sink would then end up in the dishwasher. It won't hold very much before it's all over the floor again, so really this is not a good fix.

Could easily be. Probably solidified gunk. Since it is old and brittle push fit, I would get the lot ripped out and replace everything below the tee with 50mm. Actually use a 50mm tee with

40mm reducers to go along the wall for the sink and through for the DW traps. At least it will go for longer before it gunks up. Putting a decent slope on it will also help, but I would also put a tee at the higher point where the sink trap connects and fit a screw in blank to allow a drain wire to be run along the length of the pipe outside.

Running a couple of sinkfuls of really hot water down the drain every couple of weeks won't hurt either.

For copper there are 3/4" to 22mm connectors and 1/2" to 15mm.

For waste, it all varies between pipe types and whether they are solvent or push fit. The sizes are 32mm, 40mm and 50mm.

As I say though, it would be better to rip the lot out and start again. Waste pipe and fittings are pretty cheap.

Exactly

I can think of two ways to do it.

One would be in line with the pipe and using a swept branch.

Look at

Then their part number (for example) 11908

Fit a screw plug (e.g.) 11863 into the branch.

You can then undo that and insert a spiral drain cleaner when needed.

Notice that BES have all the sizes and three colours and are pretty cheap.

The other way would be to use a right angle tee instead of an elbow at the higher point (this was the sink right?)

Part number 11818 for this. Arrange it so that the water normally follows the gentle curve and fit the plug in the end.

If there is a fair run after the pipe turns the corner of the wall, perhaps there should be one of these on the corner as well?

You can get adjustabled traps that should avoid needing to do this.

e.g. 10503

Notice that there is also a spigot device on the same page like you described. 6957

Personally, I wouldn't use one of these.

An air break and trap is a better solution and in any case this would not resolve the blocking problem.

This is about the easiest of DIY jobs that I can think of as long as you buy the right bits and follow the rules.

.andy

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[Zymurgy]

T i m wrote

Heh. my quarry tiles would laugh at a bit of water :-)

Mmm, T junction. is it into the leg of the T or the arm ?

Strip it out and renew. Breakage/splits outside isn't an issue, it'll be a pain behind kitchen cabinets (or inside cavity walls ).

Best with a trap, and as you say an upstand as high as poss within the appliance manuf. recommendations.

Pretty small bore though, and the seal of the serrated pipe over the appliance tee is a bit suspect. I have one on my drainer, I wouldn't trust a dishwasher on it at that sort of pressure.

Dunno, I used a mix of compression, solvent weld and pushfit to get around some awkward angles. Use what fits best.

I didn't bother. The old runs had a bit of fluff deposit, bit nothing that would need rodding. If it got to that point i'd probably pull it off & replace or get the pressure washer down the outlet pipe.

Yes. they have good range, and you can play around with the fittings to get the best shapes.

HTH

Cheers

Paul.