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NOTE:
Adjustment of the refrigerant charge is not required
unless the unit is suspected of not having the proper R--410A
charge.
A subcooling charging chart is attached to the inside of the
compressor access panel. The chart includes the required
liquid line temperature at given discharge line pressures and
outdoor ambient temperatures.
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.
NOTE: Allow system to operate on high stage cooling for a
minimum of 15 minutes before checking or adjusting refrigerant
charge.
IMPORTANT: When evaluating the refrigerant charge,
an indicated adjustment to the specified factory charge
must always be very minimal. If a substantial adjustment
is indicated, an abnormal condition exists somewhere in
the cooling system, such as insufficient airflow across
either coil or both coils.
1. Remove caps from low-- and high--pressure service
fittings.
2. Using hoses with valve core depressors, attach low-- and
high--pressure gauge hoses to low-- and high--pressure
service fittings, respectively.
3. Start unit and let run until system pressures stabilize.
4. Measure and record the following:
Outdoor ambient--air temperature (F [C] db).
a.
Liquid line temperature (F [C]) at TXV.
b.
Discharge (high--side) pressure (psig).
c.
Suction (low--side) pressure (psig) (for
d.
reference only).
5. Using
Cooling
Charging
compare outdoor--air temperature (F [C] db) with the
discharge line pressure (psig) to determine desired
system
operating
Figure 14).
6. Compare actual liquid line temperature with desired
liquid line temperature. Using a tolerance of 2F
(1.1C), add refrigerant if actual temperature is more
than 2F (1.1C) higher than proper liquid line
temperature, or remove refrigerant if actual temperature
is more than 2F (1.1C) lower than required liquid line
temperature.
NOTE:
If the problem causing the inaccurate readings is a
refrigerant leak, refer to Check for Refrigerant Leaks section.
Indoor Airflow and Airflow Adjustments
CAUTION
!
UNIT OPERATION HAZARD
Failure to follow this caution may result in unit
damage.
For cooling operation, the recommended airflow is
350 to 450 cfm for each 12,000 Btuh of rated cooling
capacity. For heating operation, the airflow must
produce a temperature rise that falls within the range
stamped on the unit rating plate.
NOTE: Be sure that all supply--air and return--air grilles are
open, free from obstructions, and adjusted properly.
12
Charts
(See
Figure 14)
liquid
line
temperature
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Disconnect electrical power to the unit and install
lockout tag before changing blower speed.
This unit has independent fan speeds for low stage cooling and
high stage cooling. PAR5 models have the field--selectable
capability to run an enhanced dehumidification ('DEHUM')
speed on high stage cooling (as low as 320 CFM per ton).
Coupled with the improved dehumidification associated with
low stage cooling, the DHUM speed allows for a complete
dehumidification solution independent of cooling stage. Table 3
shows the operation modes and the associated fan speeds
with each mode:
Table 3 – Operation Modes and Fan Speeds
Operation Mode
Low Stage Cooling
High Stage Cooling
High Stage Enhanced
Dehumidification Cooling
Continuous Fan
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Disconnect electrical power to the unit and install
lockout tag before changing blower speed.
The evaporator fan motor is factory set to provide 5 different fan
(See
speeds to choose from for the various operation modes (see
Table 4). All models are factory--shipped for nominal high stage
and low stage cooling airflow operation at minimum external
static pressure. See Table 2.
Table 4 – Color Coding for Indoor Fan Motor Leads
Selection of Proper Fan Speeds for Operation Modes:
Low Stage Cooling (All Models): Using Tables 6 , 7, and 8,
find the external static pressure drops for wet coil, economizer,
and filter, and add them to dry coil measured on the system.
Using this total static pressure, look up Table 5 to find the
airflows available at the total static pressure. Connect the
chosen fan speed wire to "LO COOL" connection on the IFB
Board (see Figure 11).
High Stage Cooling (All Models):Using Table 6, 7, and 8, find
the external static pressure drops for wet coil, economizer, and
filter, and add them to dry coil measured on the system. Using
this total static pressure, look up Table 5 to find the airflows
available at the total static pressure. The speed chosen must
provide airflow of between 350 to 450 CFM per ton of cooling.
Connect the chosen fan speed wire to "HI COOL" connection
on the IFB Board (See Figure 11).
WARNING
Fan Speed Tap
Connection
WARNING
Black = High Speed
Orange = Med--High Speed
Red = Med Speed
Pink = Med--Low Speed
Blue = Low Speed
LOW
HIGH
DH
LOW
51901190402
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