Ventilation (Continuous Fan); Fastener Torque Values; Start-Up, Rtu Open Controls; Start-Up, Systemvu Controls - Carrier 48GC04 Service And Maintenance Instructions

2. Turn on electrical supply and manual gas valve.
3. Set system switch selector at HEAT position and fan
switch at AUTO. or ON position. Set heating temperature
lever above room temperature.
4. The induced-draft motor will start.
5. After a call for heating, the main burners should light
within 5 seconds. If the burner does not light, then there is
a 22-second delay before another 5-second try. If the
burner still does not light, the time delay is repeated. If the
burner does not light within 15 minutes, there is a lockout.
To reset the control, break the 24 v power to W1.
6. The evaporator-fan motor will turn on 45 seconds after
burner ignition.
7. The evaporator-fan motor will turn off in 45 seconds after
the thermostat temperature is satisfied.
8. Adjust airflow to obtain a temperature rise within the
range specified on the unit nameplate.
NOTE: The default value for the evaporator-fan motor on/off de-
lay is 45 seconds. The Integrated Gas Unit Controller (IGC) modi-
fies this value when abnormal limit switch cycles occur. Based
upon unit operating conditions, the on delay can be reduced to 0
seconds and the off delay can be extended to 180 seconds. When
one flash of the LED is observed, the evaporator-fan on/off delay
has been modified.
If the limit switch trips at the start of the heating cycle during
the evaporator on delay, the time period of the on delay for the
next cycle will be 5 seconds less than the time at which the
switch tripped. (Example: If the limit switch trips at 30 sec-
onds, the evaporator-fan on delay for the next cycle will occur
at 25 seconds.) To prevent short-cycling, a 5-second reduction
will only occur if a minimum of 10 minutes has elapsed since
the last call for heating.
The evaporator-fan off delay can also be modified. Once the
call for heating has ended, there is a 10-minute period during
which the modification can occur. If the limit switch trips
during this period, the evaporator-fan off delay will increase by
15 seconds. A maximum of 9 trips can occur, extending the
evaporator-fan off delay to 180 seconds.
To restore the original default value, reset the power to the unit.
To shut off unit, set system selector switch at OFF position.
Resetting heating selector lever below room temperature will
temporarily shut unit off until space temperature falls below
thermostat setting.

Ventilation (Continuous Fan)

Set fan and system selector switches at ON and OFF positions,
respectively. Evaporator fan operates continuously to provide
constant air circulation. When the evaporator-fan selector
switch is turned to the OFF position, there is a 30-second delay
before the fan turns off.

FASTENER TORQUE VALUES

Table 25 — Torque Values
Heat shield screws
Stator motor mounting screws 23 in.-lb (2.6 Nm) ±2 in.-lb (0.2 Nm)
Fan rotor mounting screws
Limit switch screws
Fan Deck bracket screws
Condenser fan motor
mounting screws
Condenser fan hub set screw
Compressor mounting bolts

START-UP, RTU OPEN CONTROLS

IMPORTANT: SET-UP INSTRUCTIONS
Installation, wiring and troubleshooting information for
the RTU Open Controller.: "48/50FC, 48/50GC Single
Package Rooftop Units with RTU Open Controls, Start-
up, Operation and Troubleshooting Instructions." Have a
copy of this manual available at unit start-up.

START-UP, SYSTEMVU CONTROLS

IMPORTANT: SET-UP INSTRUCTIONS
Installation, wiring and troubleshooting information for
the SystemVu™ Controller.: "48/50FC 04-07, 48/50GC
04-06 Single Package Rooftop Units with SystemVu
Controls Version 1.X Controls, Start-up, Operation and
Troubleshooting." Have a copy of this manual available
at unit start-up.
62
30 in.-lb (3.4 Nm) ±2 in.-lb (0.2 Nm)
23 in.-lb (2.6 Nm) ±2 in.-lb (0.2 Nm)
50 in.-lb (5.7 Nm) ±5 in.-lb (0.6 Nm)
50 in.-lb (5.7 Nm) ±5 in.-lb (0.6 Nm)
30 in.-lb (3.4 Nm) ±3 in.-lb (0.3 Nm)
60 in.-lb (6.8 Nm) ±5 in.-lb (0.6 Nm)
65 in.-lb (7.3 Nm) +10 in.-lb (1.2Nm)