19
COMPRESSOR
ACCUMULATOR
OUTDOOR COIL
INDOOR COIL
LCS
LEGEND
HPS – High Pressure Switch
LCS – Loss of Charge Switch
Accurater
®
Metering De vice
Arrow indicates direction of flo w
TXV in Bypass
Position
Metering
Position
HP S
C03012
Fig. 23 -- Typical Heat Pump Operation, Heating Mode
LOW CHARGE COOLING
Use Cooling Charging Chart (Fig. 25). Vary refrigerant until the
conditions of the chart are met. Note that charging charts are
different from type normally used. Charts are based on charging
the units to correct subcooling for the various operating
conditions. Accurate pressure gauge and temperature sensing
devices are required. Connect the pressure gauge to the service
port on the suction line. Mount the temperature sensing device on
the suction line and insulate it so that the outdoor ambient does
not affect the reading. Indoor air CFM must be within the normal
operating range of the unit.
TO USE COOLING CHARGING CHARTS
Take the liquid line temperature and read the manifold pressure
gauges. Refer to the chart to determine what the liquid line
temperature should be.
NOTE
: If the problem causing the inaccurate readings is a
refrigerant leak, refer to Check for Refrigerant Leaks section.
INDOOR AIRFLOW AND AIRFLOW ADJUSTMENTS
PERSONAL INJURY AND UNIT DAMAGE HAZARD
Failure to follow this warning could result in personal injury
or death and possible unit component damage.
The heating and cooling operation, the recommended airflow
is 350 to 450 cfm for each 12,000 Btuh of rated cooling
capacity. For units with optional electric heat, the airflow must
not be reduced below the levels stated in Table 2.
!
WARNING
Tables 3 & 4 show both heating and cooling airflows. Refer to
these tables to determine the airflow for the system being
installed.
NOTE
: Be sure that all supply--and return--air grilles are open,
free from obstructions, and adjusted properly.
Airflow can be changed by changing the set up pins on the Easy
Select board.
Unit 604D utilizes state of the art ECM (Electronic Computated
Motor) ID Blower Motors.
Step 3 — Defrost Control
QUIET SHIFT
Quiet Shift is a field--selectable defrost mode, which will
eliminate occasional noise that could be heard at the start of
defrost cycle and restarting of heating cycle. It is selected by
placing DIP switch 3 (on defrost board) in ON position.
When Quiet Shift switch is placed in ON position, and a defrost
is initiated, the following sequence of operation will occur.
Reversing valve will energize, outdoor fan will turn off,
compressor will turn off for 30 sec and then turn back on to
complete defrost. At the start of heating after conclusion of
defrost reversing valve will de--energize, compressor will turn off
for another 30 sec, and the outdoor fan will stay off for 40 sec,
before starting in the Heating mode.
DEFROST
The defrost control is a time/temperature control which includes a
field--selectable time period (DIP switch 1 and 2 on the board)
between defrost cycles of 30, 60, 90, or 120 minutes (factory set
at 30 minutes). To initiate a forced defrost, two options are
available depending on the status of the defrost thermostat.
If defrost thermostat is closed, speedup pins (J1) must be shorted
by placing a flat head screw driver in between for 5 sec and
releasing, to observe a complete defrost cycle. When the Quiet
Shift switch is selected, compressor will be turned off for two 30
sec intervals during this complete defrost cycle, as explained
previously. When Quiet Shift switch is in factory default OFF
position, a normal and complete defrost cycle will be observed.
If defrost thermostat is in open position, and speedup pins are
shorted (with a flat head screw driver) for 5 sec and released, a
short defrost cycle will be observed (actual length is dependent
upon the selected Quiet Shift position). When Quiet Shift switch
is in ON position, the length of defrost is 1 minute (30 sec
compressor off period followed by 30 sec of defrost with
compressor
operation). On return to heating operation, compressor will
604D
