28
Figure 23. Outdoor cooling unit
connection
3.
Measure the time (in seconds) required for
the gas meter to complete one revolution.
4.
Convert the time per revolution to cubic feet
of gas per hour using Table 11.
5. Multiply the gas fl ow rate in cubic feet per
hour by the heating value of the gas in Btu
per cubic foot to obtain the fi ring rate in Btu
per hour. Example:
• Time for 1 revolution of a gas meter with
a 1 cubic foot dial = 40 seconds.
• From Table 14 read 90 cubic feet per
hour of gas.
• Heating value of the gas (obtained from
gas supplier) = 1040 Btu per cubic
foot.
• Firing rate = 1040 x 90 = 93,600 Btuh.
6.
Adjustments to the fi ring rate can be made
by adjusting the gas manifold pressure.
See the High Altitude Application section
for additional information of fi ring rate at
elevations above 2000 ft.
The manifold pressure for low and high inputs
must be set to the appropriate value for instal-
lation (see Table 1). Refer to either Table 6 for
natural gas or Table 7 for LP/propane gas to
verify the manifold pressure setting required for
your particular installation. To adjust the manifold
pressure, remove the regulator cap and turn the
adjusting screw clockwise to increase pressure
or counterclockwise to reduce pressure. Note:
Check both low and high inputs to the Table 1.
Replace the regulator cap after adjustments
are complete.
CAUTION:
Do not re-drill the burner orifi ces. If
the orifi ce size must be changed, use
only new orifi ces
.
WARNING:
To avoid electric shock, personal injury,
or death, disconnect the electric power
before performing any maintenance
.
Selecting The Cooling Airfl ow Rate
The thermostat controller communicates with the
outdoor unit to determine the proper airfl ow. The
system will operate automatically at the optimum
THRU CORE RING
TO L.V. BARRIER
THRU CORE
RING
OUTDOOR UNIT
INVERTER
OUTDOOR UNIT
CONTACTOR
R
C
W2 W
H
TWIN
DX
+
DX-
24 VAC
INTERFACE
BOARD
YELLOW
GND
DX-
DX+
CN11
T1
T1
L1
L1
BLACK
BLACK
BLA
CK
BLACK
O
.D
. UNIT
RED
WHITE
GREEN
RED
WHITE
GREEN
GND
Y
