Installation Of Vent System; Vent Pipe Preparation - A.O. Smith SERIES 100 Installation & Operating Instructions Manual

INSTALLATION OF VENT SYSTEM

THE OPTIONAL INTAKE VENTING ARRANGEMENT AND THE EXHAUST
VENTING ARRANGEMENT MUST BE INSTALLED TO RUN DIRECTLY TO THE
OUTDOORS AND NOT IN ANY WAY BE CONNECTED TO ANOTHER VENTING
SYSTEM (I.E. FURNACE, DRYERS OR SPACE HEATERS). IT IS CRUCIAL
THAT THE VENTING ARRANGEMENT BE KEPT SEPARATE FROM OTHER
VENTING SYSTEMS. IF THIS WARNING IS IGNORED, AND THE SYSTEM IS
VENTED INCORRECTLY, IT MAY CAUSE IMPROPER OPERATION, FIRE,
EXPLOSION, OR ASPHYXIATION.
1. Plan the route of the vent system from the vent termination to the planned
location of the appliance. Layout the total vent system to use the minimum
of vent pipe and elbows possible.
2. The installer may add up to a MAXIMUM OF FIFTY (50) EQUIVALENT
FEET (15.2 m) of pipe to the exhaust venting arrangement. This addition
of FIFTY (50) EQUIVALENT FEET (15.2 m) of pipe on both the intake
venting arrangement and exhaust venting arrangement must include
any 3" PVC elbows which equals (5) EQUIVALENT FEET (1.5 m) of
pipe.
Table 2. VENT LENGTH TABLE
Number 3"
of 90° Minimum
Elbows Pipe (Ft./M.)
ONE (1) 7/2
TWO (2) 7/2
THREE (3) 7/2
FOUR (4) 7/2
FIVE (5) 7/2
SIX (6) 7/2
4" PVC may be used for a MAXIMUM intake of ONE HUNDRED TWENTY
(120) EQUIVALENT FEET (36.6m) and a MAXIMUM exhaust of ONE
HUNDRED TWENTY (120) EQUIVALENT FEET (36.6m). The maximum
number of 90° elbows with the 4" venting is six (6) on the intake and six (6)
on the exhaust. A 90° elbow is equal to five (5) equivalent feet (1.5m) of
pipe. One (1) 90° elbow is equal to two (2) 45° elbows. Any venting
configuration using less than 50 equivalent feet should use 3" venting. See
Table 2.
The 3" venting terminals (provided) must be used with the
3" vent pipe. Two, approved 4" vent terminals (not provided) must be used
with 4" vent pipe. See replacement parts list for terminals.
IMPORTANT
When multiple units are direct vented through a wall (3" or 4" venting), all
intake vent terminals should be no lower than the highest exhaust vent
terminal.
NOTE: 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 D-2665 (Use CPVC fittings, ASTM F-438 for
CPVC pipe and ABS fittings, ASTM D-2661/3311 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 D-2564 Grade Cement; CPVC Materials should
use ASTM F-493 Grade Cement and ; ABS Materials should use ASTM
D-2235 Grade Cement.
WARNING
3" 4"
Maximum Maximum
Pipe (Ft./M.) Pipe (Ft./M.)
45/13.7 115/35
40/12.2 110/33.5
35/10.7 105/32
30/9.1 100/30.5
--- 95/29
--- 90/27.4
NOTE: for Water Heaters in locations with high ambient temperatures
(above 100°F or 38°C) and/or insufficient dilution air, it is recommended that
CPVC or ABS pipe and fittings (MUST USE SUPPLIED VENT TERMINAL) be
used.
4. 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, 1/8" (3mm) per 5' (152 cm) of pipe maximum downward
slope.
5. The vent system should be supported every 5' (152 cm) of vertical run
and every 3' (91cm) of horizontal run of vent pipe length.
NOTE: 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.

VENT PIPE PREPARATION

1. INITIAL PREPARATION
A. Make sure the solvent cement you are planning to use is designed
for the specific application you are attempting.
B. Know the physical and chemical characteristics and limitations of
the PVC, PVC cellular core, ABS or CPVC piping materials that you
are about to use.
C. Know the reputation of your pipe and cement manufacturer and
their products.
D. Know your own qualifications or those of your contractor. The
solvent welding technique of joining PVC, PVC cellular core, ABS or
CPVC pipe is a specialized skill just as any other pipe fitting technique.
E. Closely supervise the installation and inspect the finished job before
start-up.
F. Contact the manufacturer, supplier, or competent consulting agency
if you have any questions about the application or installation of
PVC, PVC cellular core, ABS or CPVC pipe.
G. Take the time and effort to do a professional job. Shortcuts will only
cause you problems and delays in start-up. The majority of failures
in these systems are the result of shortcuts and/or improper joining
techniques.
2. SELECTION OF MATERIALS
PRIMER
It is recommended that Tetrahydrofuran (THF) be used to prepare the
surfaces of pipe and fittings for solvent welding. Do not use water, rags,
gasoline or any other substitutes for cleaning PVC cellular core, ABS or
CPVC surfaces. A chemical cleaner such as MEK may be used.
CEMENT
The cement should be a bodied cement of approximately 500 to 1600
centipoise viscosity containing 10-20% (by weight) virgin PVC material
solvated with tetrahydrofuran (THF). Small quantities of dimethyl formamide
(DMF) may be included to act as a retarding agent to extend curing time.
Select the proper cement; Schedule 40 cement should be used for Schedule
40 pipe. Never use all-purpose cements, commercial glues and adhesives
or ABS cement to join PVC or CPVC pipe and fittings.
SAFETY PRECAUTION: PRIMERS AND CEMENTS ARE EXTREMELY
FLAMMABLE AND MUST NOT BE STORED OR USED NEAR HEAT OR
OPEN FLAME. ALSO, USE ONLY IN A WELL-VENTILATED AREA.
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