longest run for hot water

[plumber89]

what is the longest run alowed for hot water in vented system?
just wondering for two reasons
one being the time it takes hot water to reach outlet, ( i rememebr there being a reg on this)
two being the pressure must get reduced the longer the run.

is there a certain amount of pressure or flow drop per metre run of pipe,

cheers

 

[stevetheplumber]

there is a drop due to friction but on correctly sized pipe this shouldnt be a problemassuming your not working on very low head not sure there is a max length but it will depend on how long your willing to wait for hot to run secondary return will eliminate this

 

[samh]

The maximum length without a secondary return is 9metres.

 

[baron]

what is a secondary return?

 

[SimonJohns]

what is a secondary return?

Do a search. It will come up

 

[spanners1967]

hot water should not take more than 30 seconds to get to the farthest outlet

 

[Sid Viscous]

Water regs. G18.7 gives the following guidance; <12mm=20m, <22mm=12m, <28mm=8m, over 28mm=3m. This is for uninsulated pipe so presumably could go further if insulated

http://archive.defra.gov.uk/environ...y/wsregs99/documents/waterregs99-guidance.pdf