BAXI heat only flue question

[Robert Tyrrell]

I've been asked to fit a BAXI heat only 25KW in place of an old Keston Celcius 25 and the problem I have is this:

The Keston is located in the middle of the house, with the twin pipe flue running through the living room ceiling void (There are inspection hatches in the floor of the bedroom above) and I know that BAXI do a twin pipe flue so I want to (If it's possible) fit around 300mm vertically then a 93° bend before entering the horizontal plane of the flue, and then unit the horizontal part to 8mtrs.

Is this permissible?

 

[quality]

MI s will tell you

 

[Billy Bob Bob]

never done a twin flue so cant advise,you need to talk to baxi tech