LAARS U.H.E. - Installation Manual - Manual (Page 21)

The vent system must terminate so that proper clearances are maintained as cited in local codes or the latest edition
of the National Fuel Gas Code, ANSI Z223.1.73.4e and 7.8a, b as follows:
1. Do not terminate near soffit vents or crawl space or other area where condensate or vapor could create a
nuisance or hazard or cause property damage.
2. Do not terminate the exhaust vent terminal where condensate or vapor could cause damage or could be
detrimental to the operation of regulators, relief valves, or other equipment.
3. Do not terminate the exhaust vent terminal over public area or walkways where condensate or vapor
can cause nuisance or hazard.
4. The vent shall terminate a minimum of 12 inches above expected snowfall level to prevent blockage of
vent termination.
5. The manufacturer requires the centerline distances between the air intake and exhaust vent terminals to
be a minimum of 36 inches (91.4 cm) apart and the exhaust terminal elbow must extend 6 inches (15.2
cm) past the air intake terminal.
Vent pipes serving power vented appliances are classified by building codes as “vent connectors”. Required
clearances from combustible materials must be provided in accordance with information in this manual under
LOCATION OF WATER HEATER and CLEARANCES, and with National Fuel Gas Code and local codes.
NOTICE
This unit can be vented using only PVC (Class 160, ASTM D-2241 Schedule 40, ASTM D-1785;
or Cellular Core Schedule 40 DWV, ASTM F-891), Schedule 40 CPVC (ASTM F-411), or ABS
(ASTM D-2661) pipe. The fittings, other than the TERMINATIONS should be equivalent to PVC-
DWV fittings meeting ASTM F-2665. (Use CPVC fittings, ASTM F-438 for CPVC pipe and ABS
fittings, ASTM D-266/3311 for ABS pipe.) If CPVC or ABS pipe and fittings are used, then the
proper cement must be used for all joints, including joining the pipe to the Termination (PVC
material). PVC materials should use ASTM –D2564 grade cement; CPVC materials should use
ASTM F-493 grade cement; and ABS materials should use ASTM D-2235 grade cement.
For water heaters in locations with high ambient temperatures (above 100°F) and/or insufficient
dilution air, it is recommended that CPVC or ABS pipe and fittings (MUST USE SUPPLIED
VENT TERMINAL) be used.
Horizontal Installation:
In a horizontal application, it is important that condensate not be allowed to buildup in the exhaust vent pipe. To
prevent this from happening the pipe should be installed with a slight upward slope so the condensate will run
back toward the water heater. The vent 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 wall:
1. Cut two 3 1/2 in. (8.9 cm) diameter holes (for 3” (7.6 cm) diameter pipe) or 4 ½” (11.4 cm) diameter
holes (for 4” (10.2 cm) diameter pipe) in the wall with the centerline hole distances at least 36” (91.4 cm)
apart in the location where the exhaust vent and air intake terminals will exit the outside wall if vented on
the same wall.
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