Direction arrow on isolation valves.

[jrtrrror]

Hi. Can someone explain in detail which direction the arrow should face. In our house we have taps/toilets with arrows facing towards the appliance and some the opposite direction. I thought it has to face the direction of flow. Is that correct? If do, does that mean if placing an isolation valve for a tap for instance, should it point to the tap?

Why is it important that it faces the correct way? What happens if placed incorrectly?
Ta in advance.
I like detailed answers, so don't be afraid to write lots

 

[Chuck]

Why is it important that it faces the correct way? What happens if placed incorrectly?

You are begging the question; in many applications it may not be 'important'.

Installing the wrong way round may (depending on the design of the valve and the pipework) either (a) cause flow-limiting turbulence to occur at lower flow-rates thn would otherwise be the case, and (b) the isolation seal may not be quite as effective.

So, when installing or repairing, I would always fit such valves the correct way round. I would not, however, dismantle a system that was otherwise okay just to turn them round.

 

[jrtrrror]

Thanks for the reply.
Is it correct that the arrow should point towards the tap that I am going to install?
Ta

 

[ShaunCorbs]

Yes / direction of flow

 

[kozak1968]

Cheap ballofix valves don't matter, they should be put the correct way for flow, but I have seen many the wrong way round without affecting performance.

 

[AWheating]

most iso valves have no performance change if fitted backwards. if you look at how they are made you will see why they have an arrow. the internals are pushed into the valve when made, when under pressure the internals cant be pushed out.