Min distance between vertical flue and gutter

[Ant1]

Hi all,

As per diagram below (sorry it was quickly drawn), I would like to install a boiler in a lean-to.

The gutters are shown in red, how far does the flue (shown as a thick arrow pointing up) need to be from the gutter (the top gutter in red)?

 

[Ant1]

The manual of the boiler I would like to buy (i.e. Intergas Rapid Plus 25) shows the following:

However my specific set-up is not really showing, do you think I can get away with 25mm distance between the gutter and the vertical flue? Or does it have to be 300mm?

Thanks!

 

[muggles]

25mm from the gutter, 300mm from the roof surface

 

[Ant1]

Thanks Andrew!