Unvented Cylinder Installation.

[Toughie]

First time poster here...

I recently had an unvented cylinder installed replacing an old gravity fed system. The installer ran a new 22mm speed fit pipe to the unvented cylinder which he suggested would be better than copper with multiple 90 bends.

However, due to speed fit pipe requiring inserts which have a bore of approximately 15mm does this not effectively make this a 15mm pipe run?

The improvement in the shower is significant, but there is a drop in flow/pressure when another tap or shower is turned on.

Any help is appreciated

 

[Madrab]

The improvement in the shower is significant, but there is a drop in flow/pressure when another tap or shower is turned on.

Not really, that's more down to the mains dynamic pressure and flow available to the cylinder. It is true that with the inserts the effect diameter of the pipe drops, and can maybe affect the flow a little but if the dynamic pressure is high enough then all that'll really happen is it gets a little more noisy.

Were the dynamic pressure and flow figures known and discussed before the cylinder went in?