LAARS U.H.E. - Installation Manual - Manual (Page 22)

2. Use the proper PVC cement to secure the 90° exhaust vent and air intake terminals provided with the
water heater to the plastic pipes. The distance between the back edge of the 90° exhaust vent terminal
and the exterior wall (see Figure 13) must be 6 inches (12.7 cm) more for the exhaust vent terminal than
the air intake terminal. Use the proper cement or sealant and assembly procedures to secure the vent
connector joints between the terminal and the blower outlet. Provide support brackets for every 3 feet
(.91 m) of horizontal vent.
Figure 13. Typical Horizontal Direct Vent System
Vertical Installation:
Vertical venting system must be supported every 5 feet of vertical run and every 3 feet of horizontal run of vent
pipe length.
CAUTION
Failure to properly support the vent piping with hangers and clamps may result in damage to the water heater
or venting system.
Stress levels in the pipe and fittings can be significantly increased by improper installation. If rigid pipe clamps
are used to hold the pipe in place, or if the pipe cannot move freely through a wall penetration, the pipe may be
directly stressed, or high thermal stresses may be formed when the pipe heats up and expands. Install accordingly
to minimize such stresses.
Follow the following procedure to vent through the roof:
1. Cut the necessary holes through the roof and ceiling
2. Install the exhaust vent and air intake plastic pipes as shown in Figure 14. Make sure that the installation
meets the local codes and/or The National Fuel Gas Code ANSI Z223.1 (Latest Edition) or CGA/CAN
B149 Installation Code.
22