York ZF Series Installation Manual page 21

4. All piping should be cleaned of dirt and scale by
hammering on the outside of the pipe and blowing out
loose particles. Before initial start-up, be sure that all gas
lines external to the unit have been purged of air.
5. The gas supply should be a separate line and installed in
accordance with all safety codes as prescribed under
"Limitations".
6. A 1/8-inch NPT plugged tapping, accessible for test gage
connection, must be installed immediately upstream of the
gas supply connection to the unit.
7. After the gas connections have been completed, open the
main shut-off valve admitting normal gas pressure to the
mains. Check all joints for leaks with soap solution or other
material suitable for the purpose. NEVER USE A FLAME.
FIRE OR EXPLOSION HAZARD
Failure to follow the safety warning exactly could result
in serious injury, death or property damage.
Never test for gas leaks with an open flame. use a
commercially available soap solution made specifically
for the detection of leaks to check all connections. A fire
or explosion may result causing property damage,
personal injury or loss of life.
The furnace and its individual shut-off valve must be
disconnected from the gas supply piping system during
any pressure testing at pressures in excess of 1/2 PSIG.
Pressures greater than 1/2 PSIG will cause gas valve
damage resulting in a hazardous condition. If it is
subjected to a pressure greater than 1/2 PSIG, the gas
valve must be replaced.
The furnace must be isolated from the gas supply piping
system by closing its individual manual shut-off valve
during any pressure testing of the gas supply piping
system at test pressures equal to or less than 1/2 PSIG.
Threaded joints should be coated with a sealing
compound that is resistant to the action of liquefied
petroleum gases. Do not use Teflon tape.
Lp Units, Tanks And Piping
All gas heat units are shipped from the factory equipped for
natural gas use only. The unit may be converted in the field for
use with LP gas with accessory kit model number 1NP0418.
All LP gas equipment must conform to the safety standards of
the National Fire Protection Association.
Johnson Controls Unitary Products
For satisfactory operation, LP gas pressure must be 10.0 inch
W.C. at the unit under full load. Maintaining proper gas
pressure depends on three main factors:
1. The vaporization rate which depends on the temperature of
the liquid and the "wetted surface" area of the container(s).
2. The proper pressure regulation. (Two-stage regulation is
recommended).
3. The pressure drop in the lines between regulators and
between the second stage regulator and the appliance.
Pipe size required will depend on the length of the pipe run
and the total load of all appliances.
Complete information regarding tank sizing for vaporization,
recommended regulator settings, and pipe sizing is available
from most regulator manufacturers and LP gas suppliers.
LP gas is an excellent solvent and will quickly dissolve
white lead and most standard commercial compounds. A
special pipe dope must be used when assembling
wrought iron or steel pipe for LP. Shellac base
compounds such as Gaskolac or Stalastic, and
compounds such as Rectorseal #5, Clyde's, or John
Crane may be used.
Check all connections for leaks when piping is completed using
a soap solution. NEVER USE A FLAME.
FIRE OR EXPLOSION HAZARD
Failure to follow the safety warning exactly could result
in serious injury, death or property damage.
Never test for gas leaks with an open flame. use a
commercially available soap solution made specifically
for the detection of leaks to check all connections. A fire
or explosion may result causing property damage,
personal injury or loss of life.
Vent And Combustion Air
Two vent hoods and a combustion air hood (with screens) are
shipped attached to the blower housing in the blower
compartment. For units with factory installed VFD option, the
hoods and accompanying hardware are shipped inside the
gas heat section. These hoods must be installed to assure
proper unit function. All hoods must be fastened to the
outside of the gas heat access panel with the screws
provided in the bag also attached to the blower housing.
The screen for the combustion air intake hood is secured to
the inside of the access panel opening with four fasteners and
the screws used for mounting the hood to the panel. The top
flange of this hood slips in under the top of the access panel
opening when installing. Refer to Vent and Combustion Air
Hood Figure 18.
5326601-XIM-A-0117
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