Indoor Airflow And Airflow Adjustments; Unit Controls; Sequence Of Operation; Maintenance - Payne PA1Z Installation, Start-Up And Service Instructions Manual

IV. INDOOR AIRFLOW AND AIRFLOW ADJUSTMENTS
CAUTION: For cooling operation, the recommended
airflow is 350 to 450 cfm per each 12,000 Btuh of rated
cooling capacity.
Table 4 shows dry coil air delivery for horizontal discharge
units. Tables 5-7 show pressure drops.
NOTE: Be sure that all supply- and return-air grilles are open,
free from obstructions, and adjusted properly.
WARNING: Disconnect electrical power to the unit
before changing blower speed. Electrical shock can cause
personal injury or death.
Airflow can be changed by changing the lead connections of
the blower motor.
Units PA1Z024,036,048, and 060 blower motors are factory
wired for low speed operation. Units PA1Z030 and 042 are
factory wired for medium speed operation.
A. For 208/230-V Blower Motors:
The motor leads are color-coded as follows:
3-SPEED
black = high speed
blue = medium speed
red = low speed
To change the speed of the blower motor, remove the fan
motor speed leg lead from the indoor (evaporator) fan relay
(IFR) and replace with lead for desired blower motor speed.
Insulate the removed lead to avoid contact with chassis parts.
B. For 460-V Blower Motors:
The motor leads are color coded as follows:
2-SPEED
black = to purple
yellow = line
purple = to black
red
To change the speed of the blower motor from low speed to
high speed, remove the red lead from the indoor-fan relay (IFR).
Insulate the red lead to avoid contact with any chassis parts.
Separate the black lead from the purple lead. Connect the
black lead to the IFR. Insulate the purple lead to avoid con-
tact with any chassis parts.
V. UNIT CONTROLS
All compressors have the following internal-protection
controls.
A. High-Pressure Relief Valve
This valve opens when the pressure differential between the
low and high side becomes excessive.
B. Compressor Overload
This overload interrupts power to the compressor when
either the current or internal temperature become excessive,
and 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 conti-
nuity tester.
2-SPEED
black = high speed
red = low speed
= line
VI. SEQUENCE OF OPERATION
A. Fan Operation
The FAN switch on the thermostat controls indoor fan opera-
tion. 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 de-
energizes 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, the indoor-
fan motor will also run while he accessory electric heat is
energized.
NOTE: PA1Z030 and 060 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.
B. Cooling
On a call for cooling, the compressor contactor (C) and the
IFR are energized through the Y and G terminals of the ther-
mostat. On units with a compressor time-delay relay, there is
a 5-minute (± 45 sec) delay between compressor starts.
Energizing the compressor contactor supplies power to the
compressor and the outdoor (condenser) fan motor (OFM).
Energizing the IFR provides power to the IFM. When the need
for cooling has been satisfied, the OFM, compressor, and IFM
(FAN on AUTO) are deenergized. If the unit is equipped with
a 30-second delay, the indoor fan will remain energized for
30 seconds after the compressor is deenergized (030 and 060
units only).
C. Heating
If accessory electric heaters are installed, on a call for heat
the thermostat energized the W relay which energizes the elec-
tric heaters. The IFR is energized which starts the indoor-
fan motor. If the heaters are staged, W2 is energized when
the second stage of heating is required. When the need for
heating is satisfied, the heater and IFM are deenergized.
To ensure continuing high performance, and to reduce the pos-
sibility of premature equipment failure, periodic mainte-
nance must be performed on this equipment. This cooling unit
should be inspected at least once each year by a qualified serv-
ice person. To troubleshoot cooling of units, refer to Trouble-
shooting chart in back of book.
NOTE TO EQUIPMENT OWNER: Consult your local dealer
about the availability of a maintenance contract.
WARNING: The ability to properly perform mainte-
nance on this equipment requires certain expertise,
mechanical skills, tools and equipment. If you do not
possess these, do not attempt to perform any mainte-
nance on this equipment, other than those procedures
recommended in the User's Manual. FAILURE TO HEED
THIS WARNING COULD RESULT IN SERIOUS PER-
SONAL INJURY AND POSSIBLE DAMAGE TO THIS
EQUIPMENT.
—14—

MAINTENANCE