John Wood Commercial - AJWSC - Manual (Page 9)

Gas Leak Testing
Important: This water heater and its gas connection must
be leak tested before placing the appliance in operation.
• If the code requires the gas lines to be tested at a pres-
sure exceeding 14 in. w.c. (3.5 kPa), the water heater and
its manual shut-off valve must be disconnected from the
gas supply piping system and the line capped.
• If the gas lines are to be tested at a pressure less than 14
in. w.c. (3.5 kPa), the water heater must be isolated from
the gas supply piping system by closing its manual shut-
off valve.
U.L. recognized fuel gas and (CO) detectors are recom-
mended in all applications and should be installed using the
manufacturer’s instructions and local codes, rules, or regu-
lations.
Note: Air may be present in the gas lines and could prevent
the burner from lighting on initial start-up. The gas lines
should be purged of air by a qualified service technician
after installation of the gas piping system.
Air Requirements
Important: Air for combustion and ventilation must not
come from a corrosive atmosphere. Any failure due to cor-
rosive elements in the atmosphere is excluded from war-
ranty coverage.
Installations in or for certain places including, but not limited
to, those listed below will require outdoor air for combustion
to reduce the risk of chemical exposure:
• Beauty shops
• Photo processing labs
• Buildings with indoor pools
• Water heaters installed in laundry, hobby or craft rooms
• Water heaters installed near chemical storage areas
Combustion air must be free of acid-forming chemicals.
These chemicals are found in aerosol sprays, detergents,
bleaches, cleaning solvents, air freshener, paint and varnish
removers, refrigerant, and many other commercial prod-
ucts. When burned, vapours from these products form high-
ly corrosive acid compounds. These products should not be
stored or used near the water heater or air inlet.
The area in which the heater is located is classified as either
“an unconfined space” or “a confined space”.
An unconfined space is defined as a space having a vol-
ume not less than 50 cubic feet per 1000 BTU/hour (4.8
cubic meters per kilowatt) of combined input rating of all
appliances using the space. Adjacent open rooms may be
included as part of the unconfined space provided there
are no closeable doors between these rooms. An exam-
ple of this is an open basement.
A confined space is one smaller than described above. Air
shall be supplied through permanent openings as described
in Figure 4. At no time shall an air opening have a dimen-
sion of less than 76mm (3 in.) and at no time shall any top
opening be lower than the top of the water heater.
For buildings that are not well sealed (do not have tight fit-
ting doors and windows) natural air infiltration may provide
sufficient air required for combustion and ventilation. For
buildings using tight construction (newer and renovated
structures), the air supply shall be introduced from the out-
doors, regardless of whether the space is confined or
unconfined.
Where an exhaust fan or any other air consuming appliance
(e.g. clothes dryer, furnace, etc.) is installed in the same
space as the water heater, sufficient air openings must be
available to provide fresh air when all appliances are oper-
ating simultaneously.
Combustion Air “Supply” Ducts
Air supply ducts shall be of galvanized steel or equivalent
corrosion resistant material. A single air duct may not be
substituted when required for upper and lower air openings.
Horizontal upper combustion air ducts shall not slope down-
ward toward the air inlet.
WARNING
An adequate air supply shall be provided for
combustion and ventilation of this water
heater.
An insufficient supply can result in poor
combustion and possible sooting of the
burner, combustion chamber, or flue pas-
sageway. This may present a potential fire
hazard or create a serious health hazard by
producing carbon monoxide.
WARNING
Explosion Hazard
Have a qualified service technician make
sure L.P. gas pressure does not exceed 13
in. w.c. (3.24 kPa). Failure to do so can result
in death, explosion, or fire.
WARNING
Exposure to a higher gas supply pressure
may cause damage to the gas valve, result-
ing in explosion or fire. Consult your local
gas supplier and gas authorities. DO NOT
PUT INTO SERVICE IF OVER-PRESSURIZA-
TION HAS OCCURRED.
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