Isolating hot tap in kitchen

[KennyPowers]

Hi,

I'm going to replace our kitchen sink with a different one, but can't seem to find a valve that isolates the hot feed.

Where would these usually be?

I guess as a back-up, I can isolate the feed into the hot water tank upstairs, then drain the contents of it?

Thanks,
KP.

 

[Madrab]

I can isolate the feed into the hot water tank upstairs

If you have a hot water cylinder fed from an attic cistern then isolating the cylinder from that cistern via the red wheel headed gate valve should stop the hot water flow to the taps

 

[Elkato531]

There may not be an isolating valve for the kitchen tap. Turn off the cold feed to the hot water cylinder, when you run the tap, the water should stop after a minute or so as it is only draining the pipework from the top of the cylinder, not the cylinder itself. Put an isolating valve in while you're changing the tap.

 

[KennyPowers]

Thanks, I think this is the method I will have to use, as I cannot find a valve.

The tap I bought comes with two flexible tails. If I put an isolating valve on the 15mm hot (and maybe also the cold) pipe, can I just screw the tail straight into it, without the need for compression olives and extra 15mm pipe?

Also, the kitchen worktop is made of chipboard, and the underside edges crumble a bit. Is there a way to seal it in so it won't flake off? (PVA perhaps)

Cheers,
kp

 

[Newboy]

can I just screw the tail straight into it,

The risk is that the rubber washer in the female tap tail will be damaged by the sharp edge of the isolation valve.

 

[just pumps]

The risk is that the rubber washer in the female tap tail will be damaged by the sharp edge of the isolation valve.

Agree however there are isolation valves with a flat mating surface for this application.

 

[KennyPowers]

Screwfix & Toolstation appear to just do the normal ones (that may split the washer)

However, Toolstation do these: https://www.toolstation.com/shop/p6...=26799122783&gclid=CKOu38rDqcACFYzHtAodgUMA4g

So I guess adding them to standard iso valves would achieve the same thing, in that I can screw the tap tails straight onto it?

 

[Newboy]

Toolstation do these

That's the type of product - Toolstation code is 14081

 

[Newboy]

Is there a way to seal it in so it won't flake off?

Brush over a coat of varnish

 

[KennyPowers]

I did find some flat faced iso valves on ebay, however not sure I should trust cheap (chinese made?) valves not to leak https://www.ebay.co.uk/itm/BOLOFIX-...m=282358406646&_trksid=p2045573.c100507.m3226

Yep, looks like varnish is the best way to go,

Cheers
kp

 

[Newboy]

however not sure I should trust cheap (chinese made?) valves

Especially when the valves in question sound like the Chinese pronunciation of a decent brand - bolofix v. Ballofix !

 

[Madrab]

All I do with the standard ISO valves are I flat file the sharp edge off the end of the ISO that the flexi's will be on, takes the sharp edge off and gives the rubber washer a flat surface to sit on. It's softish brass so it's not a hard job, takes 2 secs.

 

[Madrab]

Also, the kitchen worktop is made of chipboard, and the underside edges crumble a bit. Is there a way to seal it in so it won't flake off? (PVA perhaps)

2/3 coats of waterproof PVA and brush it into all the exposed edges, as it's absorbed by the woodchip it consolidates it into one piece and makes it all waterproof when it's dry

 

[KennyPowers]

I guess its not worth cheaping out on iso valves, so I think I'll go with Pegler (they seem to have a good rep)

For a kitchen sink, could either full-bore or restricted-bore be used with little noticeable difference between the two?

 

[Madrab]

For a kitchen sink, could either full-bore or restricted-bore be used with little noticeable difference between the two

Depends on your current flow and pressure, full bore minimises any reduction in delivery but if you have 3 bar dynamic with a flow rate of 25L/Min, you're not liable to notice any difference with standard ISO's