5188236-BIM-A-0316
Johnson Controls Unitary Products
33
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 1NP0440 or
1NP0485 (2 Stage).
All LP gas equipment must conform to the safety standards of
the National Fire Protection Association.
For satisfactory operation, adequate LP gas pressure must be
provided at the unit manifold 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.
Check all connections for leaks when piping is completed using
a soap solution.
NEVER USE A FLAME.
Vent And Combustion Air Hoods
The vent hood and combustion air hood (with screens) are
shipped attached to the blower housing in the blower
compartment. 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 three 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 17.
The vent hood is installed by inserting the top flange of the hood
into the slotted opening in the access panel and securing in place.
The products of combustion are discharged horizontally through
this screened, hooded vent opening on the gas heat access panel.
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 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.
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.
