Isolation valve

[Spiderman]

When fitting isolation valves to hot & cold taps under the sink can somebody tell me how much pipe to cut off is it around an inch and also is it ok to use Ptfe tape as I don't have any jointing compound

 

[Whyme]

Measure the depth of each side of the valve, that will tell you how much to cut and no on the ptfe pal. thats for threads that need jointing not nuts and olives..

 

[Best]

Depends on which type of isolating valve you use. If it is the ordinary cheap & nasty Ballofix type valves, then it is about 1/2" to remove. Surely it is just a matter of you measuring how far a pipe goes into each side to find the centre cut off length?
Compress the olives & slacken back & put a couple turns ptfe over the olives to help seal them well. Paste is better.

 

[Spiderman]

Many thanks for the advice but thought I would ask as on a Youtube video the plumber said that he always cut an inch as a rule of thumb and as for the type of valves I guess they will be the cheaper ones as I will buy from wickes or online as I don't have an account at the big plumb suppliers

 

[Best]

Ignore the YouTube "plumber".
If you cut an inch off the pipe, the pipes would be slightly too short if there is no movement in them.
It is up to you what valves you use, but if you want or need better quality valves that will probably turn off properly & without leaks, even years in the future, then you can get full flow valves which also have better internal seals for another couple quid. Cheap ones will do fine though.

 

[Chalked]

Depends on which type of isolating valve you use. If it is the ordinary cheap & nasty Ballofix type valves, then it is about 1/2" to remove. Surely it is just a matter of you measuring how far a pipe goes into each side to find the centre cut off length?
Compress the olives & slacken back & put a couple turns ptfe over the olives to help seal them well. Paste is better.

Ptfe on olives! Nooooooooo

that's just for decorators who haven't got a clue.

 

[Spiderman]

Ignore the YouTube "plumber".
If you cut an inch off the pipe, the pipes would be slightly too short if there is no movement in them.
It is up to you what valves you use, but if you want or need better quality valves that will probably turn off properly & without leaks, even years in the future, then you can get full flow valves which also have better internal seals for another couple quid. Cheap ones will do fine though.

Many thanks. Can you please tell me where I can purchase them from and what names to look out for

 

[Best]

Ptfe on olives! Nooooooooo

that's just for decorators who haven't got a clue.

Well he did ask could he use ptfe as a sealant because he'd no paste! He is a diyer. :smile:

 

[Spiderman]

Well he did ask could he use ptfe as a sealant because he'd no paste! He is a diyer. :smile:

I asked about the Ptfe instead of jointing compound because a plumber on Youtube was using it and I wanted some expert advice

 

[Best]

Many thanks. Can you please tell me where I can purchase them from and what names to look out for

Depends where you are I guess. Plumb Centre or most other plumbing merchants will do both the cheap type & better types. Screwfix will probably do them. I will take a look & try to send you a link.

 

[Spiderman]

Depends where you are I guess. Plumb Centre or most other plumbing merchants will do both the cheap type & better types. Screwfix will probably do them. I will take a look & try to send you a link.

Many thanks you seem a real gent who is genuine

 

[Best]

I asked about the Ptfe instead of jointing compound because a plumber on Youtube was using it and I wanted some expert advice

And you were correct in my opinion to be following the advice of using some sort of belt & braces sealant on the olives. Ptfe is mainly for sealing threads that are a joint in themselves on male fittings. But ptfe will help improve olives seal. Paste is much superior though, as it is a fine " liquid" type sealant & it acts as a lubricant.

 

[Best]

This is the full flow version. If it has the better internal seals, then it won't leak later & it helps with flow if you have gravity fed water.
15mm Full Bore Isolating Valve | Isolating Valves | NoLinkingToThis

 

[Best]

Or you could use these, but they are maybe too good for what you need. The full flow isolating valves above ^ can also be Pegler brand. My issues with the cheap valves is they have rubber seal on the ball inside & can leak if turned. Also they tend to break inside.
Pegler Yorkshire Tee Ball Valve 15mm Red | Ball Valves | NoLinkingToThis

 

[Best]

Many thanks you seem a real gent who is genuine

Really appreciate that! It's rare to get a polite reply from people newly posting, if any at all! :smile:
Most on this forum are genuine & try to help anyone who is decent. I am the 'Best', though! :grin:

 

[Whyme]

No slight on any previous posts but no ptfe tape doesn't belong on olives, best advise or not..

 

[Best]

No slight on any previous posts but no ptfe tape doesn't belong on olives, best advise or not..

I agree. Best avoided. :smile: Never really like ptfe on olives. It tends to get torn apart when the joint compresses. Often better than no jointing material used though.
Jet Lube is my choice.

 

[AWheating]

Sometimes you will come across a fitting that won't seal very well then ptfe will come out. That's more to do with the cheap fitting or bad install tho tbh.

 

[WaterTight]

ptfe, which costs nothing and can be applied in seconds without getting goo on your fingers like paste, works perfectly on olives and irrespective of where it's "meant to be used" (whatever on earth that means) it works every time without fail.

if a joint leaks even with ptfe round the olive, using paste instead will not sort it. re-doing the joint will. and the joint that was fine without either for years and years that develops a weep will be sorted by the application of either.

it's one of those absurd snobberies in plumbing.

 

[Spiderman]

This is the full flow version. If it has the better internal seals, then it won't leak later & it helps with flow if you have gravity fed water.
15mm Full Bore Isolating Valve | Isolating Valves | NoLinkingToThis

Many thanks for taking the time to seek the information for me and the cheaper ones seem a good choice with good reviews