Indoor Airflow And Airflow Adjustments; Unit Controls; High- -Pressure Relief Valve; Compressor Overload - Payne PA3Z Installation Instructions Manual

9. Add charge using the service connection on the suction line
of the compressor.
Step 4 — Indoor Airflow and Airflow Adjust-
ments
NOTE: For cooling operation, the recommended airflow is 350
to 450 cfm for each 12,000 Btuh of rated cooling capacity.
Table 5 shows dry coil air delivery for horizontal discharge units.
Tables 7- -9 show pressure drops.
NOTE: Be sure that all supply- - and return- -air grilles are open,
free from obstructions, and adjusted properly.
WARNING
!
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.
Airflow can be changed by changing the lead connections at the
blower motor. To change motor speeds, reposition wire at fan
motor speed terminals labeled 1- -2- -3- -4 (refer to Fig. 12).
Remove the speed tap connector labeled 1 through 5 and the
motor. While looking at the connector end that is inserted into the
motor, gently pry the locking tab outward and remove the wire
from the connector. Insert the wire into the desired tap until it locks
into place. Be sure new airflow meets the range noted above and
minimum electic heat CFM, if equipped. Refer to Table 2 and 5.
All model sizes are factory wired for rated airflow operation.
Fig. 12 - - Motor Speed Selection
FOR 208/230V BLOWER MOTORS
The motor lead speed connections are as follows:
SIZE RATED AIRFLOW
024 Tap 1
030 Tap 2
036
Tap 1
042 Tap 2
049
Tap 3
RATED AIRFLOW
SIZE
Low High
Stage Stage
048 Tap 1 Tap 3
060 Tap 1 Tap 3
A08210
HIGH AIRFLOW
Tap 3
Tap 4
Tap 3
Tap 4
Tap 4
HIGH AIRFLOW
Low High
Stage Stage
Tap 2 Tap 4
Tap 2 Tap 4
Step 5 — Unit Controls
All compressors have the following internal- -protection controls.

HIGH- -PRESSURE RELIEF VALVE

This valve opens when the pressure differential between the low
and high side becomes excessive.

COMPRESSOR OVERLOAD

This overload interrupts power to the compressor when either the
current or internal temperature
automatically resets when the internal temperature drops to a safe
level.
This overload may require up to 60 minutes (or longer) to reset;
therefore, if the internal overload is suspected of being open,
disconnect the electrical power to the unit and check the circuit
through the overload with an ohmmeter or continuity tester.

COMPRESSOR ROTATION

On 3- -Phase units it is important to be certain compressor is
rotating in the proper direction. To determine whether or not
compressor is rotating in the proper direction:
1. Connect service gages to suction and discharge pressure
fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge pressure
should rise, as is normal on any start- -up.
If the suction pressure does not drop and the discharge pressure
does not rise to normal levels:
1. Turn off power to the unit and tag disconnect.
2. Reverse any two of the unit power leads.
3. Turn on power to the unit.
The suction and discharge pressure levels should now move to
their normal start- -up levels.
NOTE: When the compressor is rotation in the wrong direction,
the unit makes an elevated level of noise and does not provide
cooling.
Step 6 — Sequence of Operation

FAN OPERATION

The FAN switch on the thermostat controls indoor fan operation.
When the FAN switch is placed in the ON position, the IFR
(indoor- -fan relay) is energized through the G terminal on the
thermostat. The normally- -open contacts close, which then provide
power to the indoor (evaporator) fan motor (IFM). The IFM will
run continuously when the FAN switch is set to ON.
When the FAN switch is set to AUTO, the thermostat deenergizes
the IFR (provided there is not a call for cooling). The contacts open
and the IFM is deenergized. The IFM will be energized only when
there is a call for cooling or if the unit is equipped with accessory
electric heat.
NOTE: Some units are equipped with a time- -delay relay. On
these units, the indoor fan remains on for 30 seconds after G or Y
is deenergized.
COOLING OPERATION (SIZES 024- -042 and 049)
With a call for cooling (Y/Y2), the indoor fan energizes
immediately whereas the contactor energizes after a 5 minute time
delay (in case of initial start- -up) starting the compressor and the
outdoor fan motor. When the cooling demand is met, Y/Y2
de- -energizes, shutting the compressor, indoor fan and the outdoor
fan.
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become excessive, and