Immergas VICTRIX EXTRA 12 PLUS Instructions And Recommendations page 37

Extensions for Ø 60/100 vertical kit (Fig. 22)
C
33
The kit with this configuration can be extended up to a maximum
of 14.4 m vertical straight, including the terminal; this configura-
tion corresponds to a resistance factor of 100. In this case specific
coupling extensions must be requested.
22
37