14
Table 6. Manifold Pressure (in WC) for LP/Propane Gas at Various Altitudes
Table 5. Manifold Pressure (in WC) for Natural Gas at Various Altitudes and Heating Values
See
Figure 10
or the unit wiring label for proper high
and low voltage wiring. Make all electrical connections in
accordance with all applicable codes and ordinances.
Use a separate branch electrical circuit for this unit. A
means of electrical disconnect must be located within
sight of and readily accessibility to the unit.
The unit is shipped from the factory wired for 240 volt
transformer operation. For 208 volt operation, remove
the lead from the transformer terminal marked 240V and
connect it to the terminal marked 208V. For maximum
circuit ampacity and maximum over current protection,
see the unit rating plate or
Table 7.
Overcurrent protection must be provided at the branch
circuit distribution panel and sized as shown in
Table 7
or on the unit rating label and according to the National
Electric Code and applicable local codes.
Provide power supply (or supplies) for the unit in
accordance with the unit wiring diagram, and the unit rating
plate. Connect the line-voltage leads to the corresponding
terminals on the contactor inside the control compartment.
Use only copper wire for the line voltage power supply
to this unit. Use proper code agency listed conduit and
a conduit connector for connecting the supply wires to
the unit and for obtaining proper grounding. Grounding
may also be accomplished by using the grounding lug
provided in the control box. Do not use gas piping as an
electrical ground.
CAUTION:
To avoid personal injury or property damage,
make certain that the motor leads cannot
come into contact with any uninsulated metal
components of the unit.
Blower Speed —
The blower speeds are preset at the
factory. See
Table 3
for factory settings. For optimum
system performance and comfort, it may be necessary
to change the factory set speed. To change the blower
speed:
1. Disconnect all electrical power to the unit and remove
the blower panel.
2. Locate the orange, red and blue wires terminated to
the blower motor. The orange wire controls cooling
operation while the red wire controls heating operation.
The blue wire controls fan-only operation.
3. Verify the required speed from the airfl ow data found
in table 3. Place appropriate wire on the appropriate
motor speed tap for the required airfl ow point.
For a Natural Gas Sea Level Heating Value of 800 to 899 Btu/ cu.ft.
Elevation (feet above sea level)
zero to
1999
2000 to
4999
5000 to
5999
6000 to
7999
8000 to
10000
Manifold Pressure Setting (in WC)
3.5
3.5
3.5
3.5
3
For a Natural Gas Sea Level Heating Value of 900 to 999 Btu/ cu.ft.
Elevation (feet above sea level)
zero to
1999
2000 to
4999
5000 to
5999
6000 to
7999
8000 to
10000
Manifold Pressure Setting (in WC)
3.5
3.5
3.5
3.2
2.8
For a Natural Gas Sea Level Heating Value of 1000 to 1100 Btu/ cu.ft.
Elevation (feet above sea level)
zero to
1999
2000 to
4999
5000 to
5999
6000 to
7999
8000 to
10000
Manifold Pressure Setting (in WC)
3.5
3.5
3
2.8
2.5
Elevation (feet above sea level)
zero to
1999
2000 to
4999
5000 to
5999
6000 to
7999
8000 to
10000
Manifold Pressure in (WC) Based on Sea Level
LP Heating Value of 2,500 Btu/ft.3
10
8.5
10
9
8.5
Orifi ce Size
3.5
3.5
3.5
3.5
3
