Viessmann Flue gas system Installation Instructions Manual page 27

Vertical outlet for sloping or flat roofs (cont.)
Fit the above-roof extension
System size 60 and 80
26
1. Push the internal pipe of above-roof
extension 1 onto roof outlet 2 and secure
with 3 screws provided.
2. Push black pipe section 3 onto roof outlet
2 and secure with 3 screws provided.
3. Push roof outlet 2 with above-roof
extension 1 onto the balanced flue.
4. Secure the above-roof extension (1000 mm
long) with clip 4 provided and with guy
ropes.