LAARS HWG-M2-250 - Installation, Operation and Maintenance Instructions - Manual (Page 5)

9600 HWG Water Heater Page 5
If a 4" pipe size is used to permit longer vent
runs the installer must supply 4" hubless couplings (2)
and 3 x 4 bushings (2) to adapt to the unit fittings. 4"
inlet and exhaust screens are provided for installation
in contractor provided 4" coupling and elbow
terminations.
NOTE: It is required that a minimum separation
of 18" be maintained between the intake and exhaust
terminals and that both terminals be installed on the
same wall of the building. The intake terminal must
not be installed above the exhaust terminal since this
would tend to pull exhaust gases back into the intake
(see Figures 2 and 3).
2.3 Locating Vent Openings on Outside Wall
1. Exhaust terminal location.
The exhaust terminal fitting requires a 4" (10cm)
diameter hole through the outside wall. The
center line of this opening must be at least 18"
(46cm) above grade and at least 14" (35.6cm)
from any other building opening such as doors,
windows, etc.
Vent opening should be well away from
shrubbery or other obstructions that would block
or restrict the exhaust.
Whenever possible, locations under windows or
near doors should be avoided. Steaming at the
flue terminal is a normal occurrence. This should
be considered when deciding flue terminal
position.
2. Intake terminal location.
The intake terminal requires a separate 4"
(10cm) diameter hole to install the intake fitting.
The center line of the hole should be at least 16"
(41cm) above grade outdoors and 18" (46cm)
away from the exhaust outlet. The intake should
never be located above the exhaust terminal.
3. Intake and exhaust location for multiple unit
installation. For the installations of multiple
units, refer to Figure 4 for intake and exhaust
terminal locations.
2.4 Locating Unit for Proper Vent Height
The vent locations you select must permit direct
pipe runs to the terminal from the boiler. Since the
9600 HWG Water Heater is designed to drain any
water that collects in the vent, it is important that you
do not build any traps or low points into the vent
where water could collect and restrict the vent. It is
recommended that 1/4" per foot of vent be built into
the vent system to direct any water in the vent back
toward the boiler. Note that standard DWV elbows
have a built in allowance for the required 1/4" per foot
pitch.
2.5 Locating Unit with Respect to Ventilation
While the 9600 HWG Water Heater requires no
indoor air for combustion, adequate airflow around
the unit must be provided for proper cooling of
electrical components.
Figure 4. Multiple units minimum vent terminal
separation.
EXHAUST
INTAKE
Exhaust
Terminal
Figure 3. Alternate vent terminal installations.
NOTE: If flue passes through a flat
roof with parapet walls exhaust terminal
level must be above the level of the wall.
If flue passes through a sloped or
peaked roof it is not necessary to locate
it to conform with location requirements
for conventional chimneys.
Typical Soil Pipe
Flashing Acceptable
Intake
Terminal
18"
Min.
Roof terminals for air
intake must prevent
entry of rain water.
2.6 Locating Unit with Respect to
Storage Tanks
For the best results the 9600 HWG Water Heater
should be located within 10 feet of the storage tanks.
If the unit must be installed with longer piping
runs, then the larger diameter tubing must be used.
Calculate the necessary pipe size for your installation
(see Table 2).
SECTION 3.
Installation
3.1 Installing Vent Piping Terminal
The water heater is provided with intake and
exhaust terminals for use with 3" diameter plastic
pipe.
The installer is responsible for obtaining the vent
pipe and fittings. The maximum combined length of
the intake and exhaust pipe and maximum number of
elbows are determined by using the guidelines on Page
4.