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C. To Use the Cooling Charging Chart
Use the above temperature and pressure readings, and find
the intersection point on the cooling charging chart. If inter-
section point on chart is above line, add refrigerant. If inter-
section point on chart is below line, carefully recover some of
the charge. Recheck suction pressure as charge is adjusted.
NOTE: Indoor-air cfm must be within normal operating
range of unit. All outdoor fans must be operating.
The TXV (thermostatic expansion valve) is set to maintain
between 15 and 20 degrees of superheat at the
compressors. The valves are factory set and should not
require re-adjustment.
D. Perfect Humidity™ System Charging
The system charge for units with the Perfect Humidity
option is greater than that of the standard unit alone. The
charge for units with this option is indicated on the unit
nameplate drawing. To charge systems using the Perfect
Humidity dehumidification package, fully evacuate, recover,
and re-charge the system to the nameplate specified charge
level. To check or adjust refrigerant charge on systems using
the Perfect Humidity dehumidification package, charge per
the standard subcooling charts. The subcooler MUST be
deenergized to use the charging charts. The charts reference
a liquid pressure (psig) and temperature at a point between
the condenser coil and the subcooler coil. A tap is provided
on the unit to measure liquid pressure entering the sub-
cooler (leaving the condenser).
IX. GAS VALVE ADJUSTMENT
A. Natural Gas
The gas valve opens and closes in response to the thermostat
or limit control.
When power is supplied to valve terminals D1 and C2, the
main valve opens to its preset position.
The regular factory setting is stamped on the valve body
(3.3 in. wg).
To adjust regulator:
1. Set thermostat at setting for no call for heat.
2. Turn main gas valve to OFF position.
3. Remove
1
/
8
-in. pipe plug from manifold or gas valve
pressure tap connection. Install a suitable pressure-
measuring device.
4. Set main gas valve to ON position.
5. Set thermostat at setting to call for heat.
6. Remove screw cap covering regulator adjustment
screw (see Fig. 43).
7. Turn adjustment screw clockwise to increase pres-
sure or counterclockwise to decrease pressure.
8. Once desired pressure is established, set thermostat
setting for no call for heat, turn off main gas valve,
remove pressure-measuring device, and replace
1
/
8
-in. pipe plug and screw cap.
X. MAIN BURNERS
For all applications, main burners are factory set and should
require no adjustment.
A. Main Burner Removal
1. Shut off (field-supplied) manual main gas valve.
2. Shut off power to unit.
3. Remove unit control box access panel, burner section
access panel, and center post (Fig. 4-6).
4. Disconnect gas piping from gas valve inlet.
5. Remove wires from gas valve.
6. Remove wires from rollout switch.
7. Remove sensor wire and ignitor cable from IGC
board.
8. Remove 2 screws securing manifold bracket to
basepan.
9. Remove 2 screws that hold the burner support plate
flange to the vestibule plate.
10. Lift burner assembly out of unit.
NOTE: Dimensions are in inches.
Fig. 40 — Condenser Fan Adjustment, 580F180, 210, 300
NOTE: Dimensions are in inches.
Fig. 41 — Condenser Fan Adjustment, 580F240
50
40
100
150
200
250
300
350
400
60
80
100
120
140
ALL OUTDOOR FANS MUST BE OPERATING
LIQUID PRESSURE AT LIQUID VALVE (PSIG)
LIQUID TEMPERATURE AT LIQUID VALVE (DEG F)
BOTH CIRCUITS
REDUCE CHARGE IF BELOW CURVE
ADD CHARGE IF ABOVE CURVE
Fig. 42 — Cooling Charging Chart