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Seems silly though when the simple calculation tells you that the 22 should be fine
 
Totally agree Shaun it just seems daft when we are all using one type of calculation and then the manufacturer tells you you need to up size it. If there is a factor to take into account with their product then they should make you aware of this otherwise quite legitimately you are going to do your pipe sizing calculation and only find out when the thing is connected that it doesn't work. It hardly seems fair for them to refuse the warranty when you have actually done the due diligence of calculating the pipe sizes
 
Actually, as per the Viper book, I calculated the pipe size required to carry 3.75m3/h and its 28mm :/ it's because the pipework from the meter doesn't branch until it hits the boiler when it tees to the hob. I just hope that the section I up to 28mm is enough.
 
Didn't work! Got another 0.15 m3/h - now have to take up the floor to replace the rest of the run as the guy don't want it run externally..
 
Pipework from meter is 22mm, goes in house and under floor in 22mm approx 3-3.5m. Comes out of floor where boiler is in 15mm.
no one else seems to be asking this so.
does the size change from 22 to 15 at some point under the floor?
how much 15mm pipe is there?
that will starve the flow dramatically!
 
no one else seems to be asking this so.
does the size change from 22 to 15 at some point under the floor?
how much 15mm pipe is there?
that will starve the flow dramatically!

It changes under the floor and no idea where.. so going to replace the rest of the run with 28 until it hits underneath the boiler which it'll then be 15 for about 500mm and tee off in 15 for the hob for about 1.5m
 
no one else seems to be asking this so.
does the size change from 22 to 15 at some point under the floor?
how much 15mm pipe is there?
that will starve the flow dramatically!


I've asked about the 15mm!

I also asked about the hob and its burner setting!

I'd look at that before running 28mm
 
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