Gas Heating (48Pg Units) - Carrier 48PG03-16 Controls, Start-Up, Operation, Service And Troubleshooting Instructions

Units Without Humidi- -MiZert System
The outdoor fan speed, number, and location for each of three
levels is defined for each cooling circuit in the Circuit submenus
(Configuration→COOL→CIR.x).
configurations are shown in Table 88. The fan level selected
during operation is based on factory configurations of outdoor
temperature limits and condenser pressure limits. These are in
the Outdoor Fan
(Configuration→COOL→OFC). Initial fan level starts at zero
and increments to level 1 when Fan LEV0 Max Pressure limit is
reached. Changes between levels 1 to 3 are initially selected based
on outdoor air temperature (OAT) input and the level On and Off
temperature limits. The levels may be further adjusted based on
the circuit saturated
(Temperatures→REF.T→SCT.x) and the level Max and Min
pressure limits.
Units With Humidi- -MiZer System
Outdoor fan control for Humidi-MiZer units includes a
Motormaster® variable-speed control of some or all outdoor fans,
depending on unit size. The Motormaster control automatically
adjusts the outdoor fan speed to maintain approximately 80 to
100_F condenser temperature for circuit A at all outdoor ambient
temperatures. Some unit sizes have additional on/off staging of
some outdoor fans. The fan level operation is determined by
some or all Outdoor Fan Control configurations described above,
plus additional Humidimizer
(Configuration→HZMR).
For 48/50PG03-07 units, one outdoor fan is controlled in all
modes by the Motormaster
48/50PG08-14 units, 2 outdoor fans are controlled in all modes
by the Motormaster sensing circuit A. For 48/50PG16 units, 3
outdoor fans are controlled in normal cooling and subcooling
Reheat1 modes by the Motormaster sensing circuit A. Two of the
fans are additionally controlled with the OFC.1 output, based on
outdoor temperature, during the hot-gas Reheat2 mode (level 1 =
1 fan, level 2 = 3 fans).
Table 88—Fan Level Control of Outdoor-Fan
FAN LEVEL SIZES 03-07
0
Off
1
Lo Speed
2
Hi Speed
3
Hi Speed

Gas Heating (48PG Units)

For 48PG units, the
Configuration→HEAT→HT.TY will be factory set to a value of
1.
Heat will not operate if the outdoor temperature is greater than the
value configured for the
Configuration→HEAT→HT.LO.
Configuration→HEAT→MRT.H,
Configuration→HEAT→MOT.H, timeguards apply to both
stages of heating. Factory default values are 2 minutes On and
2 minutes Off. The IGC minimum on-time of 1 minute will be
followed even if MRT.H is lower and during Service Test.
If the indoor fan control is configured to cycle with the heating
demand (Configuration→UNIT→OC.FN = No) the fan will
stop after a configured delay, Configuration→ HEAT→FOD.G.
Factory default value is 45 seconds. If the IGC temperature limit
switch opens within 10 minutes of the end of the gas heating, the
next fan off delay will be extended by 15 seconds. The maximum
delay is 3 minutes. Once modified by the IGC, the fan off delay
will not change back to FOD.G unless power is reset to the
control.
Results of the factory
Control submenu
condensing temperatures
Configuration
sensing circuit A. For
SIZES 08-14 SIZE 16
Off Off
Fan 1 Fan 1
Fan 1 and 2 Fan 1, 2 and 3
Fan 1 and 2 Fan 1, 2 and 3
heat type configuration
heat lockout temperature,
Minimum on-time,
and minimum off-time,
A light-emitting-diode (LED) is provided on the IGC to
indicate its status. During normal operation the LED is
continuously on. See the Troubleshooting section if the LED is
off or flashing. The IGC is located behind gas section access
panel. See Fig. 8 for location.
Thermostat Control
When the thermostat calls for heating, the MBB senses that W1 is
On and closes the HT.1 relay. When the relay is closed, it sends
power to W on the IGC (integrated gas unit controller) board. An
LED (light-emitting diode) on the IGC board will be on during
normal operation. A check is made to ensure that the rollout
switch and limit switch are closed. The induced-draft motor is
then energized. When speed is proven with the Hall Effect sensor
on the motor, the ignition activation period begins.
The burners will ignite within 5 seconds. If the burners do not
light, there is a 22-second delay before another 5-second
attempt. If the burners still do not light, this sequence is repeated
for 15 minutes. After the 15 minutes have elapsed, if the burners
still have not ignited, heating is locked out. The control will
reset when the request for heat is temporarily removed.
When ignition occurs, the IGC board will continue to monitor the
condition of the rollout switch, limit switches, Hall Effect sensor,
and the flame sensor. If the unit is controlled through a room
thermostat set for fan auto, 45 seconds after
indoor-fan motor will be energized (and the outdoor-air dampers
will open to their minimum position). If for some reason the
overtemperature limit opens prior to the start of the indoor fan
blower, on the next attempt, the 45-second delay will be
shortened to 5 seconds less than the time from initiation of heat to
when the limit tripped. Gas will not be interrupted to the burners
and heating will continue. Once modified, the fan on delay will
not change back to 45 seconds unless power is reset to the
control.
When additional heat is required and the MBB senses that W2 is
On, the MBB will turn on the HT.2 relay which sends power to
the second stage of the main gas valve. If the thermostat removes
the call for W2, the unit will turn off HT.2. If W1 is satisfied, the
MBB will turn off HT.1 which will turn off gas to the main
burners.
If the user has selected Adaptive (see Cooling section) for its
thermostat mode, the algorithm will follow the configurable
delays for adding and removing stages. When adding additional
heat stages, the delay is measured from when the last stage was
added (Configuration→HEAT→H.INC).
stages, the delay is measured from when the last stage was
removed (Configuration→HEAT→H.DEC). Therefore, if W1
and W2 turn on simultaneously, the second stage will turn on
after a H.INC delay.
NOTE: If the mode is not Adaptive, then there are no delays for
adding and removing stages.
Space Sensor Control
To operate the unit in Space Sensor mode, set the Unit Control
Type to 3 (Configuration→UNIT→U.CTL=3). To enable
heating during space temperature control, a jumper wire must be
added between R and W1 on the field connection terminal strip
(see Major System Components section for wiring diagrams).
Because Space Sensor mode is an "Auto" mode, the control will
switch between cooling and heating to maintain space
temperature. However, to minimize unnecessary changes, there is
a 10-minute mode select timeguard (Operating Modes→
HEAT→MS.TG) after the last stage of cool turns off before
heating is allowed.
64
ignition occurs the
When removing