I'll be fitting a shower in my downstairs bathroom shortly.
I have two choices for the pipe work ...

1. Down from upstairs HW tank, through existing duct, under the ground
floor flooring, then along to the bathroom, and up to the shower.

or

2. Along under the upstairs floorboards, between joists, and down into
the bathroom.

Which should I go for? Bear in mind I'll have a shower pump installed
near to the HW tank. Does it make anydifference? (Down then along will
be significantly longer).

-Kenny

kmillar wrote:
I'll be fitting a shower in my downstairs bathroom shortly.
I have two choices for the pipe work ...

1. Down from upstairs HW tank, through existing duct, under the ground
floor flooring, then along to the bathroom, and up to the shower.

or

2. Along under the upstairs floorboards, between joists, and down into
the bathroom.

Which should I go for? Bear in mind I'll have a shower pump installed
near to the HW tank. Does it make anydifference? (Down then along will
be significantly longer).

Shorter is better, with the same vertical drop.
Having the horizontal before or after the vertical makes no difference
in the flow of water, only the overall vertical drop, number of bends,
guage of pipework.

Thanks for that. There will certainly be far fewer bends in the 'along
then down' method, although it means more disruption to the house.
(Need to pull up floor boards in 3 rooms upstairs).

Guage of the pipework will be 15mm as this is the size specified by the
pump manufacturer.

-Kenny

kmillar wrote:
Thanks for that. There will certainly be far fewer bends in the 'along
then down' method, although it means more disruption to the house.
(Need to pull up floor boards in 3 rooms upstairs).

Guage of the pipework will be 15mm as this is the size specified by the
pump manufacturer.

The pressure drop across this 15mm pipe will be greater than 22mm pipe will
cause less pressure loss, but has more dead volume of cold water in the pipes.
This may not be an issue.

Good luck.

May be worth considering a coil of plastic pipe.
You can often thread it through places you would need to lift floorboards
for copper pipe.