Advertisement
PGD4 Series K WPG4 Series K: Installation Instructions
Heating Sequence of Operation
(See
Fig.
16,
Fig. 17
and unit wiring label)
On a call for heating, terminal W of the thermostat is energized, starting
the induced-draft motor for a 5 second pre-purge. When the pressure
switch senses that the induced-draft motor is moving sufficient
combustion air, the burner sequence begins. This function is controlled
by the integrated gas unit controller (IGC). The indoor (evaporator) –fan
motor is energized 30 seconds after flame is established. When the
thermostat is satisfied and W is de-energized, the burners stop firing and
the indoor (evaporator) fan motor shuts off after a 90 second time-off
delay. Please note that the IGC has the capability to automatically reduce
the indoor fan motor on delay and increase the indoor fan motor off
delay in the event of high duct static and/or a partially-clogged filter.
Limit Switches
Normally closed limit switch (LS) completes the control circuit. Should
the leaving-air temperature rise above the maximum allowable
temperature, the limit switch opens and the control circuit "breaks." Any
interruption in the control circuit instantly closes the gas valve and stops
gas flow to the burners. The blower motor continues to run until LS
resets.
When the air temperature at the limit switch drops to the
low-temperature setting of the limit switch, the switch closes and
completes the control circuit. The direct-spark ignition system cycles
and the unit returns to normal heating operation.
Table 6 – LED Indications
STATUS CODE
*
Normal Operation
No Power or Hardware Failure
Check fuse, low voltage circuit
Limit Switch Fault
Flame Sense Fault
Four Consecutive Limit Switch Faults
Ignition Lockout Fault
Pressure Switch Fault
Rollout Switch Fault
Internal Control Fault
Temporary 1 hr auto reset
*. LED indicates acceptable operation. Do not change ignition control board.
†. This code indicates an internal processor fault that will reset itself in one hr.
Fault can be caused by stray RF signals in the structure or nearby. This is a
UL requirement.
NOTES:
1. When W is energized the burners will remain on for a minimum of 60 sec.
2. If more than one error code exists they will be displayed on the LED in
sequence.
Rollout Switch
The function of the rollout switch is to close the main gas valve in the
event of flame rollout. The switch is located above the main burners.
When the temperature at the rollout switch reaches the maximum
allowable temperature, the control circuit trips, closing the gas valve and
stopping gas flow to the burners. The indoor (evaporator) fan motor
(IFM) and induced draft motor continue to run until switch is reset. The
IGC LED will display FAULT CODE 7.
Step 3 – Start-up Cooling and Make Adjustments
Complete the required procedures given in the Pre-Start-Up section
before starting the unit. Do not jumper any safety devices when
operating the unit. Do not operate the compressor when the outdoor
temperature is below 40°F (4.4°C) (unless accessory low-ambient kit is
installed). Do not rapid-cycle the compressor. Allow 5 minutes between
on cycles to prevent compressor damage.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
LED INDICATION
On
Off
1 Flash
2 Flashes
3 Flashes
4 Flashes
5 Flashes
6 Flashes
7 Flashes
8 Flashes
†
9 Flashes
Checking Cooling Control Operation
Start and check the unit for proper cooling control operation as follows:
1. Place room thermostat SYSTEM switch in OFF position. Observe
that blower motor starts when FAN switch is placed in ON position
and shuts down when FAN switch is placed in AUTO position.
2. Place SYSTEM switch in COOL position and FAN switch in
AUTO position. Set cooling control below room temperature.
Observe that compressor, condenser fan, and evaporator blower
motors start. Observe that cooling cycle shuts down when control
setting is satisfied. The evaporator fan will continue to run for 90
sec.
3. When using an auto-changeover room thermostat, place both
SYSTEM and FAN switches in AUTO positions. Observe that unit
operates in Heating mode when temperature control is set to call for
heating (above room temperature) and operates in Cooling mode
when temperature control is set to call for cooling (below room
temperature).
IMPORTANT: Three-phase, scroll compressors are direction oriented.
Unit must be checked to ensure proper compressor 3-phase power lead
orientation. If not corrected within 5 minutes, the internal protector will
shut off the compressor. The 3-phase power leads to the unit must be
reversed to correct rotation. When turning backwards, the difference
between compressor suction and discharge pressures will be minimal.
Checking and Adjusting Refrigerant Charge
The refrigerant system is fully charged with R-410A refrigerant and is
tested and factory sealed. Allow system to operate a minimum of 15
minutes before checking or adjusting charge.
!
EXPLOSION HAZARD
Failure to follow this warning could result in
death, serious personal injury, and/or property
damage.
Never use air or gases containing oxygen for
leak
compressors. Pressurized mixtures of air or
gases containing oxygen can lead to an
explosion.
NOTE: Adjustment of the refrigerant charge is not required unless the
unit is suspected of not having the proper R-410A charge.
NOTE: Some units have fixed orifice refrigerant metering devices.
There is a different charging procedure for both expansion devices.
Refer to the correct procedure for your unit.
The charging label and the tables shown refer to system temperatures
and pressures in cooling mode only. A refrigerant charging label is
attached to the inside of the compressor access panel. (See
Subcool chart for units with TXV and superheat chart for units with
fixed orifice.) The chart includes the required liquid line temperature at
given discharge line pressures and outdoor ambient temperatures.
A superheat chart is attached to the inside of the compressor access panel
for the unit with fixed metering device. Refer to the charging procedure
on the label.
An accurate thermocouple- or thermistor-type thermometer, and a gauge
manifold are required when using the subcooling charging method for
evaluating the unit charge. Do not use mercury or small dial-type
thermometers because they are not adequate for this type of
measurement.
26
WARNING
testing
or
operating
refrigerant
Table 8
Advertisement
