Horizontal venting system (sealed combustion)
Vertical venting system with flex PP (sealed
With Flex Pipe the maximum length is reduced by 60%, (applies
only to the section in flex PP). Example: 10 feet of flex PP is
equivalent to 25 feet of rigid PP.
Flex Pipe according to the suppliers instructions for use in the
vertical part of the installation only.
4.6.5 Connecting the condensate water drain
Risk of condensate pipe freezing!
▶ Do not install condensate drain tubing in areas where it may
Appliance condensate drain installation
The appliance comes equipped with an internal condensate
drain and siphon. This drains condensation formed in the
secondary heat exchanger. Piping must be installed under the
condensate drain outlet on the water heater and piped for
disposal in accordance with local codes.
To install the condensate drain, connect a ¾"NPT adapter on
the water heater.
Appliance drain installation
 Condensate drain connection
Installing an additional breather downstream in not necessary
since this function is already included in the heater.
Greentherm T9900 SE/i – 6 720 813 635 (2019/03)