Flexi hoses and isolation valves

[Robomonkey]

Hi All

I'm going to install a shower mixer on my gravity fed system.

Since its a gravity fed system I want to avoid introducing any issues which will reduce my already very low pressure.

I've read posts about cheap full bore isolation valves not being full bore, which sounds just plain wrong, and also that flexi hoses reduce the bore and flow rate.

Are ther good manufacturers out there that supply full bore fitting? I've rad Conex is good?

Thanks

 

[happyflyer]

If you have low head on a shower MV only use 15 mm gate valves, take a ballofix valve and a gate valve and look down the hole and then make up your mind, some ballofix only have half the 15 mm dia through them and flexible even worse, flexible have a small diameter over a greater length. Top photo ballofix end on bottom flexible end on, 15 mm gate valve is near full dia

 

[Robomonkey]

Thanks, the photos are really helpful.

i don't understand why they don't just make them bigger?

Are Conex fittings good?

 

[happyflyer]

Thanks, the photos are really helpful.

i don't understand why they don't just make them bigger?

Are Conex fittings good?

Size is why they don't make them bigger, gate valves were around 55 year before ballofix, yes Conex and Kuterlite are good, if you buy a tap now with flexible you won't run them off a tank feed system, too much pressure drop in the flexible.

 

[Best]

You can get full bore isolating valves that are fairly cheap. They look just like a wider version of the ordinary iso's.
If you look carefully inside them & you see a white seal around the ball, then it should be decent enough quality hopefully.
Lever valves are my favourite - if you have room for the lever. There are valves with small levers. (Some of the gas valves will do water or oil). Peglers are one manufacturer of very good valves.
IMO, avoid all flexis if possible, especially if you have poor flow/pressure.

 

[Robomonkey]

Thanks for the advice chaps, I'll see what my local merchant has.

 

[Plumbstar Tom]

check the shower too as some work better on low pressures, most manufactures will tell you the expected flow rate depending on your pressure

 

[Robomonkey]

I know my pressure is 0.1 at the shower, and 0.2 at the bath, everything I've bought is labelled for low pressure systems within these parameters, and I've got a mira shower, and bristan taps.

i hadn't appreciated these would be affected by flexi's or isolation valves.

ive never done plumbing before and the flexi's are quite attractive for ease of installation, now I'm think I might have to spend a bit more time and try and get the copper right upto the fittings, it seems to me this is a real skill of measurement and experience.

 

[happyflyer]

I know my pressure is 0.1 at the shower, and 0.2 at the bath, everything I've bought is labelled for low pressure systems within these parameters, and I've got a mira shower, and bristan taps.

i hadn't appreciated these would be affected by flexi's or isolation valves.

ive never done plumbing before and the flexi's are quite attractive for ease of installation, now I'm think I might have to spend a bit more time and try and get the copper right upto the fittings, it seems to me this is a real skill of measurement and experience.

Static pressure is one thing, but when the water starts to flow that is another.

 

[Paulus]

In my experience anything designed for low pressure will work but the flow will be absolute rubbish. I bet you finish up adding a pump.