Full bore pushfit isolation valve

[ReX83]

Ah, I was tempted by their no-name stop ends at the weekend but the reviews put me right off. I stick with Hep2O and it's been good to me..apart from the pricetag.

I find this no-brand material of good quality. Actually the connectors have a clever design where the metal spring (that keeps the pipe in place) is behind the o-ring (and not in front), so the spring doesn't score/mark the pipe where the o-ring will sit. I have seen other brands and the order of o-ring and metal blades/spring is reversed, so the pipe can get micro scratches.

I've been aware of angles reducing flow for a while but I recently redid a kitchen where the predecessor didn't own a pipe bender so the pipework resembled a rubics cube (they'd litterally created squares of pipework to eventually get it pointing the way they wanted) .There was a minimum of 12 angles used between stop tap and kitchen tap - I ripped it all out and now there are 2 angles (one on each h/c)and only pipe bends...I'm still getting used to the new found water pressure/flow! It was an amazing difference, previously hot water took ages to get there and was sporadic.

Interesting. I have 6 angles along the line that brings the water to the garden tap and the pipe is 15mm. I wonder if the pressure washer would work much better if I remove those angles.

That's like saying the speedlimits been changed to 50mph an hour I may aswell just do 40mph everywhere (which some people admittedly do!). On branded kit I've seen the inserts restrict diameter about 10% a normal isolation valve would restrict a FURTHER 10% (minimum).

Ahah - good point. My point was: if you have 10% diameter reduction at any point of your line and you add another 10% reduction along the line, will the pressure/flow be further reduced?

I use full-bore valves where I isolate flow to a segment of the house

Makes sense.

 

[StopHammerTime]

I find this no-brand material of good quality. Actually the connectors have a clever design where the metal spring (that keeps the pipe in place) is behind the o-ring (and not in front), so the spring doesn't score/mark the pipe where the o-ring will sit. I have seen other brands and the order of o-ring and metal blades/spring is reversed, so the pipe can get micro scratches.

That is a fair point and always my worry with plastic pipe - is the outer pristine enough for a good seal, worse to have in the back of your mind the actual fitting could be ruining it.

Interesting. I have 6 angles along the line that brings the water to the garden tap and the pipe is 15mm. I wonder if the pressure washer would work much better if I remove those angles.

Give it a go if you're having problems with it. I'll add, the house I noticed this on had poor/acceptable incoming water pressure due to very narrow lead pipes so I think the further upstream problems were amplified by that. If you're in the same boat,definitely give it a go.

Ahah - good point. My point was: if you have 10% diameter reduction at any point of your line and you add another 10% reduction along the line, will the pressure/flow be further reduced?

I'd say it does but not sure if I'm equipped with the brain/words to articulate why - especially as we think your unbranded stuff is as narrow as an isolation valve* (my point below was actually based on isolation valves adding further reduction). I think on a short run/domestic, realistically you probably would never know, but idealy you want everything you do to be causing the best flowrate possible. Whenever I use plastic pipe I always think back to when I was taught to deburr copper pipe - one of the many reasons is to 'avoid water turbulance', well heck if a fraction of a millimeter of copper upsets the water - what the hell does 6 4mm metal inserts every metre or two do?
I'd guess it's probably the same rule in Physics as to why you run your main rad conduits (flow and return pipes) in 22mm when the branches off it go to 15mm ... why not just use 15mm throughout?


*I would double check that as it means your pipework is really restrictive. After seeing this thread I put a hep2o insert in an isolator and looked through it and it's clear the pipe insert is a bigger diameter than the valve.

 

[DP]

Shouldn't use PTFE on compression fittings, and certainly not on plastic, the water pressure will encourage the fitting to part company with the pipe.

Lost me there fella.
How will the pipe blow out of the compression fitting.
While not saying PTFE is needed, I would not hesitate to apply PTFE tape if the unions are old and have had to dismantle these
ALSO, PTFE is often applied incorrectly to the fitting thread. Can never understand what the logic is

 

[ReX83]

That is a fair point and always my worry with plastic pipe - is the outer pristine enough for a good seal, worse to have in the back of your mind the actual fitting could be ruining it.

To be on the safe side I try to protect the end of the pipes when I need to run them trough cavities. When it is required to cut them, I usually inspect the pipe and move the cut accordingly, if there is any visible sign.
Mind you: I am just an engineer with a passion for DIY . Actually... let me use this opportunity to ask a completely off-topic question: I am replacing a bathtub... do you use any sealant when installing the drain and overflow (e.g. Plumbers Mait)?

I would double check that as it means your pipework is really restrictive.

I'll check again but if I am not mistaken both inserts and valves have a 10mm inner diameter on a 15mm pipe.

I think that all the inserts and reductions create venturi effect that adds more stress on the o-rings and pipework in general. I still think it is neglectable, so maybe we are just talking about a non-problem here!
I also wonder how long these o-rings will last. I read that if properly lubricated their elasticity should remain unaltered for at least 50-60 years. Who knows!

 

[DP]

I read that if properly lubricated their elasticity should remain unaltered for at least 50-60 years. Who knows!

Most boilers now rely on O rings for coupling integrity. O rings deform and leak for fun in boilers where life of steamers is around 10 years

 

[ReX83]

Most boilers now rely on O rings for coupling integrity. O rings deform and leak for fun in boilers where life of steamers is around 10 years

If I am not mistaken, also my Biasi boiler has o-rings.

I think that's due to the temperature, rubber quality and placement. Researches indicate that the temperature and lubrication play a very big role in their lifetime (e.g. https://www.sciencedirect.com/science/article/pii/S014139102030210X).
Also car engines relies on o-rings and even if there are aggressive liquids in play, very often they don't leak!

 

[StopHammerTime]

To be on the safe side I try to protect the end of the pipes when I need to run them trough cavities. When it is required to cut them, I usually inspect the pipe and move the cut accordingly, if there is any visible sign.
Mind you: I am just an engineer with a passion for DIY . Actually... let me use this opportunity to ask a completely off-topic question: I am replacing a bathtub... do you use any sealant when installing the drain and overflow (e.g. Plumbers Mait)?



I'll check again but if I am not mistaken both inserts and valves have a 10mm inner diameter on a 15mm pipe.

I think that all the inserts and reductions create venturi effect that adds more stress on the o-rings and pipework in general. I still think it is neglectable, so maybe we are just talking about a non-problem here!
I also wonder how long these o-rings will last. I read that if properly lubricated their elasticity should remain unaltered for at least 50-60 years. Who knows!

Protecting ends is a must, not just for scratches but you dont want to get flakes of wood etc in the pipe from joists as it'll never get back out.

Personally I use plumbers gold or CT1, it pains me everytime as the seals are designed to do a job and I'm undermining that - but that's what I do. Sometimes if the seals look particularly good quality (almost exclusively mcalpine) I won't - but plasticy hard ones that come with the appliance are almost unanimously siliconed. On sinks I use plumbers mait, I guessI can't say it's the right or wrong answer, like a lot of these things it's always worked for me so I don't deviate. I was dying to open my gob on the PTFE on compression fitting comment but we'll save that for another day!

RE. Seals - Yes, I like classic vehicles and I've had 60's machines with in-tact engine seals. I'm going to speak before I think - but I'm surprised there isn't a lubricant type of additive that can go in systems with inhibitor etc.

 

[StopHammerTime]

duplicate post

 

[ReX83]

ersonally I use plumbers gold or CT1, it pains me everytime as the seals are designed to do a job and I'm undermining that - but that's what I do. Sometimes if the seals look particularly good quality (almost exclusively mcalpine) I won't - but plasticy hard ones that come with the appliance are almost unanimously siliconed. On sinks I use plumbers mait

So, for bathtub drains, you remove the original seals and use silicon or you put silicon on the two sides of the each seal?
First time I used Plumbers Mait was due to a sink drain that started leaking right after installation - I was surprised as the seal was new and it was very tightly installed. In the end I assumed it was due to poor surface below the sink.

 

[StopHammerTime]

So, for bathtub drains, you remove the original seals and use silicon or you put silicon on the two sides of the each seal?
First time I used Plumbers Mait was due to a sink drain that started leaking right after installation - I was surprised as the seal was new and it was very tightly installed. In the end I assumed it was due to poor surface below the sink.

I use Plumbers Mait on sinks, I think against porcelain, especially a rounded surface it's better. On baths and showers where generally there is a flat mating surface (make sure it's suitably prepared and not rough - I've had to sand them down before) I put a bead of silicone around the seals. Never do away with the bottom seal, you can however often exchange the top seal exclusively for silicone - dry assemble it and see what the profile is like with all the seals before you make that call. I can only ever recall doing this on sinks (usually kitchen ones) though.
Wipe off the excess so it's not a pain in the future and don't get any on the threads.

I'll point out, I am not a plumber by trade. I think the kindest description for me is 'multitrade' however I'm yet to have a leak .

 

[StopHammerTime]

No idea where the delete post button is :S

 

[denso13]

I am replacing a bathtub... do you use any sealant when installing the drain and overflow (e.g. Plumbers Mait)?

Personally, no. Basins yes, but nothing else.

 

[ReX83]

On baths and showers where generally there is a flat mating surface (make sure it's suitably prepared and not rough - I've had to sand them down before) I put a bead of silicone around the seals. Never do away with the bottom seal, you can however often exchange the top seal exclusively for silicone

So you leave the bottom seal as it is - dry and use sealant with the top or in place of the top. Why this?

Personally, no. Basins yes, but nothing else.

Why basins yes and bathtubs no?

 

[StopHammerTime]

So you leave the bottom seal as it is - dry and use sealant with the top or in place of the top. Why this?

No - other way round. I often put silicone on the seals, especially the bottom one, I don't generally leave any out of the assembly. IF i were to leave one out of the assembly it would be the top one and I'd use a lot of silicone on the top part of the waste/drainer instead of the seal.

In terms of why that one; I guess first off the top of my head is the bottom one is less accessible and even harder to monitor, it's also the one that's most likely to leak - if youve got a loose top part it'll either be apparent on use or will be so slight water will take the easiest route...down the drain hole. I also think of the sink waste as a nut and bolt - the lower part is the nut and more likely to undo the sealant prevents this. I guess that's the main reason I don't trust seals alone - the wastes on these are usually plastic construction which means you have to be careful not to overtighten them and its also hard to tighten them sufficiently, not to mention the material itself expands and contracts so could loosen. If you have a good rubbery seal this can't happen as much ,it acts like a crush washer and locks everything in place - on plastic/hard ones you're best with a little glob of silicone to be sure it won't go anywhere and also make sure every crevace is filled (it will expell any excess when tightening). Thin plastic constructed wastes with hard seals are the worst , I generally swap them out for Mcalpine unless they are really accessible like kitchen sinks. Shower - you never want to go back there, take your time and do it right. Bath is a bit more accessible if it has an access panel.

 

[ReX83]

I often put silicone on the seals, especially the bottom one

I suppose on both sides of the seal, right?