For satisfactory operation, L.P./propane gas pressure must be 10.0 I.W.C. at the unit manifold under full load. Maintaining proper gas pressure depends on three main factors:
1.The vaporization rate depends on (a) the tempera- ture of the liquid and (b) the "wetted surface" area of the container or containers.
2.The proper pressure regulation.
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 appli- ances.
Complete information regarding tank sizing for vapor- ization, recommended regulator settings, and pipe siz- ing is available from most regulator manufacturers and L.P./propane gas suppliers.
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 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 install- ing. Refer to Vent and Combustion Air Hood Figure 8.
Each 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 horizon- tally through these two screened, hooded vent open- ings on the upper gas heat access panel.
L.P./propane gas is an excellent solvent and special pipe compound must be used when assembling piping for this gas as it will quickly dissolve white lead or most standard commercial compounds. Shellac base com- pounds such as Rectorseal #5 are satisfactory for this type of gas.
Check all connections for leaks when piping is com- pleted, using a soap solution. NEVER USE A FLAME.
FIRE OR EXPLOSION HAZARD
VENT AIR
OUTLET
HOODS
COMBUSTION AIR INTAKE HOOD
SLOTTED OPENINGS IN ACCESS PANEL
GAS HEAT
ACCESS
PANELS
FAILURE TO FOLLOW THE SAFETY WARN- ING EXACTLY COULD RESULT IN SERIOUS INJURY, DEATH OR PROPERTY DAMAGE.
NEVER TEST FOR GAS LEAKS WITH AN OPEN FLAME. USE A COMMERICALLY AVAILABLE SOAP SOLUTION MADE SPE- CIFICALLY FOR THE DETECTION OF LEAKS TO CHECK ALL CONNECTIONS. A FIRE OR EXPLOSION MAY RESULT CAUS- ING PROPERTY DAMAGE, PERSONAL INJURY OR LOSS OF LIFE.
VENT AND COMBUSTION AIR HOODS
Two vent hoods and a combustion air hood (with screens) are shipped attached to the blower housing in
FIGURE 8 - VENT AND COMBUSTION AIR HOOD
OPTIONAL ECONOMIZER/MOTORIZED DAMPER RAIN HOOD
The instruction for the optional economizer/motorized damper rain hood can be found in the kit. Use these instructions when field assembling an economizer rain hood onto a unit. The outdoor and return air dampers, the damper actuator, the damper linkage, the outdoor and return air divider baffles, and all the control sen- sors are factory mounted as part of the "Factory installed" economizer option.
16 | Johnson Controls Unitary Products |
