How many double check valves are too many?

[Super_Paulie]

is this too many double check valves, am i going overboard on having them on the taps?

 

Dishwasher feed needs one for sure, but what about the fridge water supply, that thing will be full of all sorts of left over kebabs etc.

 

Any thoughts welcome.

[ProDave]

We have ONE just after the sopcock on the incoming water.  What makes you think you need more than that one?

[Super_Paulie]

My likely incorrect thinking is: 

 

- Tap could get dirty while cleaning, sending contaminated water back down into the mains. 

 

- Fridge water could contact something like meat or fish, going back through. (Unlikely)

 

- Dishwasher, well I thought all appliances needed one.

 

Happy to be told otherwise if my thinking is off.

[BotusBuild]

You only need one after the stopcock inside the house.

 

We have one on the build tap outside which will remain in place, as it is direct connection back to the meter.

[Super_Paulie]

Is that right. Hmm, my thinking is off here then. So basically I don't need any DCV's here?

[BotusBuild]

I don't think so. Isolator valves for future maintenance, sure, but not DCV's

[Super_Paulie]

doing the work tonight i hope in my under sink, does anyone have any interesting ideas on how to make this more "elegant" or is this as good as it'll get? Do away with the drain cocks and just deal with a mouthful of water at maintenance time?

Edited June 25 by Super_Paulie

[BotusBuild]

You could put the drain taps inline in those vertical pipes above the connectors if you have room.

 

Also, you lose some joins by following the green lines below 

[Super_Paulie]

i was trying to keep everything over to the left hand side to keep the majority of the unit free of pipes. Probably a waste of time to be fair and like you say its just introducing more joints. The pipes coming in from underneath can be anywhere in the unit so im not restricted in that sense.

[Nickfromwales]

Firstly, you would be using single check valves and defo not double check. The double check is for the water authority approval for connection at the stopcock. The point of these going in at the kitchen sink taps and appliances etc, to prevent reverse contamination, is kosher, but most are fitted with non return (single check) valves by manufacture, and washing machine taps can be bought with an integral NRV LINK which kills two birds with one stone (and satisfies the regs requirement there).

 

For the kitchen sink tap, just use these LINK in the 15mm x 1/2" male union that will be used to connect the 1/2" flexi tails that come supplied. Check first if the tap you've chosen doesn't already come with these in the kit supplied. Tap may also have 3/8" connections so that needs to be confirmed.

 

With your drawing, you'd have an isolator and then a tap for the washing machine, so the isolator on that run is way OTT afaic.

 

Isolators for the hot / cold / appliance make sense, but usually the fridges have a skinny hose that ends in the sink unit with a washing machine sized adaptor to take their flexi feed hose to the water feed, and you'd just install another washing machine tap under the sink for that, therefore no need for the isolator.

 

I've not ever fitted drain off's under sinks as when the water is shut off at the SC you just open the sink taps to drain the house down, and then chuck an old towel down and get a pot or tray in there to catch the remaining couple of pints. You can box clever and mount the washing machine tap for the fridge down low, and use that as your drain off . Pointless having drain off's on the washing (appliance) taps, as they are the drain off points when you remove the hose.

 

IIRC the fridge filters are changed without turning off the water supply anyways.

 

Doesn't need to be elegant, just neat, functional, and not leak lol. 

Edited June 25 by Nickfromwales
Added info and second link

[Super_Paulie]

are you saying like the attached @Nickfromwales, single check valves above the isolators with the flexi straight to them? i was really wanting to use these nice full bore Peglers for my isolation as the standard ones ive had the handle sheer off before with undesirable results, plus the Peglers look the nuts. In the attached i have one of those single check/washing machine valves you linked to, but i guess i could use a pegler and a single check here as well like the taps?

As for the fridge, i already have a 5m 10mm pipe in place, which reduces to 8mm at the fridge so there is not a lot i can do about that as it is all under the floor already.

[Nickfromwales]

12 minutes ago, Super_Paulie said:

are you saying like the attached @Nickfromwales, single check valves above the isolators with the flexi straight to them?

Yes, so you can isolate and then service the NRV’s with ease.

 

13 minutes ago, Super_Paulie said:

i was really wanting to use these nice full bore Peglers for my isolation as the standard ones ive had the handle sheer off before with undesirable results, plus the Peglers look the nuts.

Fill your boots. 
 

Not had many washing machine taps fail, as they’re operated once in a blue moon. Turn on and walk away tbh. Up to you. 

[Super_Paulie]

Cheers guys, I've finished the job apart from cutting in the shelf. Bottle trap with separate stand pipe for the dishwasher and turns out I could also guide the 8mm fridge feed down through the 10mm pipe I already had in place which meant I could bring the 8mm feed straight into the cabinet manifold. Just need a few check valves for the tap flexi's.

 

Cheers for all the input, onwards and upwards.

[MikeSharp01]

Very tidy👌

[Nickfromwales]

2 hours ago, Super_Paulie said:

Cheers guys, I've finished the job apart from cutting in the shelf. Bottle trap with separate stand pipe for the dishwasher and turns out I could also guide the 8mm fridge feed down through the 10mm pipe I already had in place which meant I could bring the 8mm feed straight into the cabinet manifold. Just need a few check valves for the tap flexi's.

 

Cheers for all the input, onwards and upwards.

Very nice bit of plumbing squire 👌.  

[BotusBuild]

I've got a job for you 🙂

[jack]

Much better job than any of the many plumbers I've used over the years!

[Alan Ambrose]

That’s crazy neat, congrats. What are the ‘grommets’ you used through the cabinet floor?

[Super_Paulie]

13 hours ago, Alan Ambrose said:

That’s crazy neat, congrats. What are the ‘grommets’ you used through the cabinet floor?

 

They are black talon pipe collars, 2x15mm and a 10mm for the fridge feed. Just needed to take a slice off them to fit against the back of the cabinet. 

 

Pretty happy with it, and spent far too much time on it obviously.

 

[Nickfromwales]

45 minutes ago, Super_Paulie said:

and spent far too much time on it

...........absolutely the correct amount of.........

 

👌