John Wood Atmospheric Gas (Standard) - Manual (Page 8)

8
IMPORTANT: The water heater should be located in an area
where leakage of the tank or connections will not result in
damage to the area adjacent to the water heater or to lower
floors of the structure. Due to the normal corrosive action of
water, the tank will eventually leak after an extended period
of time. Also any external plumbing leak, including those
from improper installation, may cause early failure of the
tank due to corrosion if not repaired. If the homeowner is
uncomfortable with making the repair a qualified technician
should be contacted. A suitable metal drain pan should be
installed under the water heater as shown below, to help
protect the property from damage which may occur from
condensate formation or leaks in the piping connections or
tank. The pan must limit the water level to a maximum depth
of 1-3/4” (4.45 cm) and be two inches (5 cm) wider than the
heater and piped to an adequate drain. NOTE: The metal
drain pan must not restrict combustion air flow. Locate the
water heater near a suitable indoor drain. Outside drains are
subject to freezing temperatures which can obstruct the drain
line. The piping should be at least 3/4” ID and pitched for
proper drainage.
METAL
DRAIN
PAN
AT LEAST 2 in. (5 cm) GREATER
THAN THE DIAMETER OF THE
WATER HEATER.
PIPED TO AN
ADEQUATE DRAIN
12 in. (300 mm)
MAXIMUM
AIR GAP
DISCHARGE PIPE
(DO NOT CAP OR PLUG)
FIGURE 1B.
Water heater life depends upon water quality, water usage,
water temperature and the environment in which the
water heater is installed. Water heaters are sometimes
installed in locations where leakage may result in property
damage, even with the use of a drain pan piped to a
drain. However, unanticipated damage can be reduced
or prevented by a leak detector or water shut-off device
used in conjunction with a piped drain pan. These devices
are available from some plumbing supply wholesalers and
retailers, and detect and react to leakage in various ways:
• Sensors mounted in the drain pan that trigger an alarm
or turn off the incoming water to the water heater when
water is detected.
• Sensors mounted in the drain pan that turn off the
water supply to the entire home when water is detected
in the drain pan.
• Water supply shut-off devices that activate based on
the water pressure differential between the cold water
and hot water pipes connected to the water heater.
• Devices that will turn off the gas supply to a gas water
heater while at the same time shutting off its water supply.
REVERSE FLOW
OF GASES
EXHAUST FAN
FIGURE 1C.
Clearances and Accessibility
NOTE: Minimum clearances from combustible surfaces are
stated on the rating plate adjacent to the gas control valve/
thermostat of the water heater.
The water heater is certified for installation on a
combustible floor.
•
IMPORTANT: If installing over carpeting, the carpeting
must be protected by a metal or wood panel beneath
the water heater. The protective panel must extend
beyond the full width and depth of the water heater by
at least three inches (7.62 cm) in any direction; or if in
an alcove or closet installation, the entire floor must be
covered by the panel.
• Figure 2 may be used as a reference guide to locate
the specific clearance locations. A minimum of 24
inches (61 cm) of front clearance should be provided
for inspection and service.
BACK
SIDES
TOP
VIEW
SIDES
VENT
FRONT
24 in.
(61 cm)
MINIMUM
FOR SERVICE
TOP
TO
CEILING
FIGURE 2.