Plumbing Dishwasher from scratch.

[Jeremy Home]

Hi
I want to put a dishwasher where fridge currently resides.
I’m considering doing this myself, but wanted some advice first. See on photo that there is a water pipe, which comes from outside (to right), goes behind cooker to sink. There’s a waste pipe coming from sink, behind cooker then to outside, but is buried in wall behind fridge.
I’ve seen these self cutting taps and waste drains. (See attached)
Seemed like a fairly straightforward job until I realised I would have to chisel out around the waste pipe and water pipe to get these fitted. Also seemed simpler than drilling a hole to outside and putting separate waste pipe in.
The waste would attach to a spigot, as opposed to a stand pipe, and it’s made for a washing machine, so maybe not appropriate for dishwasher drain.?
I thought the gap between sink and dishwasher would be too long to plumb to there, but perhaps I can swap washing machine to warm feed, and attach dishwasher to cold?
Lot’s questions, and a bit daunting, so any advice (apart from the obvious of paying for someone else to do it as a last resort) would be massively appreciated. Thanks

 

[CBW]

Do you definitely know it’s a water pipe, and not a gas pipe? You could always swap the sink trap for a washing machine trap, also if you’re unsure if the pipe is water, you could use one of the feeds in the sink area. I personally wouldn’t use the self cutting tap, but rather use a pipe slice or hacksaw and a washing machine tee.

 

[Jeremy Home]

Do you definitely know it’s a water pipe, and not a gas pipe? You could always swap the sink trap for a washing machine trap, also if you’re unsure if the pipe is water, you could use one of the feeds in the sink area. I personally wouldn’t use the self cutting tap, but rather use a pipe slice or hacksaw and a washing machine tee.

 

[Jeremy Home]

Hi Chris Pretty sure it’s a water pipe, as there’s an outside tap directly adjacent, and the cooker is all electric.
Linking it all up under sink would be simplest solution providing waste pipe and hose can stretch. There’s a cookers width between.
Haven’t bought the dishwasher yet, so not sure long these are. Thanks

 

[CBW]

You can purchase extension pieces for the waste hoses.

 

[Jeremy Home]

You can purchase extension pieces for the waste hoses.

Cheers, just seen them. Might be the way to go then. Thanks

 

[Hugh Jaleak]

+1 for Chris's advice. Those self cutting taps are universally disliked by the Pro's, spend a bit more time and money and do it properly. If you cut the pipe with a Pipe Cutter you can use the 'Push fit' fittings on the copper if you're unhappy using anything else. (I wouldn't attach the Washing machine to a hot supply, it'll cost you a fortune in hot water over time.)

Waste, check your dishwasher Manufacturers instructions, (some dont like the drain hose being extended), but if you do, take it right up to the top of the underside of the worktop as it leaves the void, then drop down to the drain point. Avoid any sections where water can accumulate. Alternatively, (and ideally), if there is room behind the cooker, run a waste pipe through from the existing sink setup to the void and fit a Standpipe on the wall.

 

[Jeremy Home]

+1 for Chris's advice. Those self cutting taps are universally disliked by the Pro's, spend a bit more time and money and do it properly. If you cut the pipe with a Pipe Cutter you can use the 'Push fit' fittings on the copper if you're unhappy using anything else. (I wouldn't attach the Washing machine to a hot supply, it'll cost you a fortune in hot water over time.)

Waste, check your dishwasher Manufacturers instructions, (some dont like the drain hose being extended), but if you do, take it right up to the top of the underside of the worktop as it leaves the void, then drop down to the drain point. Avoid any sections where water can accumulate. Alternatively, (and ideally), if there is room behind the cooker, run a waste pipe through from the existing sink setup to the void and fit a Standpipe on the wall.

 

[Jeremy Home]

Hi Hugh
Thanks. I’m most grateful for the advice.
Do you think this would work (photo) if it was tee d into the pipe at the back of the where the dishwasher is going?.
That pipe goes straight to a tap on outside wall.
You can see the other end of it on the other attached photo. It’s got a valve on it, and it’s going out to the right. Not sure why there’s an earth cable.
If so, how do you get it in after cutting a section out? Just bend the pipe a bit?
Regards the waste, is there a trap which could replace the one under the smaller of the two sinks , which I can attach pipe to? I can’t seem to find one online, but then not sure what I’m searching for .
Thanks again.

 

[Hugh Jaleak]

Earth cable is probably for 'Bonding' it ensures electrical safety, and must be maintained. Slotting a plastic fitting into the pipe will break the continuity, really need to join the pipes either side of the tee to maintain continuity. If you cut the required section out the pipe to fit the Tee, you should find there's enough 'spring' in the pipes to slot the Tee in, but I'd be wary of putting it behind the appliance, ideally needs to be easily accessible so it can be exercised, (turned off and back on) occasionally, or it will seize, and wont work when you most need it to!

Trap, FloPlast Telescopic Adaptor Trap 40mm | Traps | Screwfix.com Ensure drain hose falls gently from machine to drain point though, you dont want water stagnating in the hose.

 

[imroberts]

Do you think this would work (photo) if it was tee d into the pipe at the back of the where the dishwasher is going?.

The other thing to consider is many dishwashers are required to push right back to the wall. Often the top of the dishwasher will touch the wall and there'll be a (small) gap of about half an inch behind the rest of the dishwasher. Generally speaking though you won't fit a tap, waste pipe, or a plug and socket behind, so you'll probably need to fit these in the adjacent cupboard.