Carrier PA4G, Installation Instructions Manual

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PA4G: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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interface board (IFB). Verify that static pressure is in the acceptable
range for the speed tap to be used for dehumidification cooling.
7. Use any spare vinyl plugs to cap any unused speed tap wires.
A09059
Fig. 11 – Interface Fan Board (IFB)
Single Speed Cooling with Higher Electric Heat Speed
This unit can also be configured to operate with single speed cooling and
a higher speed for an accessory electric heater.
1. Using Fig. 11 , move the two pin DEHUM jumper from the “STD”
position to the “DEHUM” position.
2. See Table 2 for minimum airflow for electric heat operation. Add
electric heater and filter pressure drop to duct system static pressure
to determine total external static pressure.
3. Select speed tap from Table 5 that will achieve required airflow
from Table 2 .
4. Remove the vinyl cap off of the desired speed tap wire (Refer to
Table 3 for color coding).
5. Connect the desired speed tap wire to the “HIGH” terminal on the
interface fan board (IFB).
–
Continuous Fan Operation
When the DEHUM feature is not used, the continuous fan speed will be
the same as cooling fan speed. When the DEHUM feature is used, the
continuous fan will operate on IFB “LOW” speed when the DH control
lead is not energized, or IFB “HIGH” speed when the DH lead is
energized (see Fig. 11 ).
Cooling Sequence of Operation
With the room thermostat SYSTEM switch in the COOL position and
the FAN switch in the AUTO position, the cooling sequence of operation
is as follows:
When the room temperature rises to a point that is slightly above the
cooling control setting of the thermostat, the thermostat completes the
circuit between thermostat terminal R to terminals Y and G. These
completed circuits through the thermostat connect contactor coil (C)
(through unit wire Y) and time delay relay (TDR) (through unit wire G)
across the 24-V secondary of transformer (TRAN).
The normally open contacts of energized contactor (C) close and
complete the circuit through compressor motor (COMP) to condenser
(outdoor) fan motor (OFM). Both motors start instantly.
A set of normally open contacts on the interface fan board (IFB) are
closed which energizes a circuit to the indoor fan motor (IFB).
NOTE: Once the compressor has started and then has stopped, it should
not be started again until 5 minutes have elapsed.
The cooling cycle remains on until the room temperature drops to a point
that is slightly below the cooling control setting of the room thermostat.
At this point, the thermostat breaks the circuit between thermostat
terminal R to terminals Y and G. These open circuits deenergize
contactor coil C and IFB. The condenser and compressor motors stop.
After a 90-second delay, the blower motor stops. The unit is in a standby
condition, waiting for the next call for cooling from the room thermostat.
CAUTION
!
UNIT OPERATION HAZARD
Failure to follow this caution may result in unit component damage or
improper operation.
To use this mode, a speed connection must be made on the “HIGH”
terminal that meets or exceeds the minimum airflow found in Table 2 .
HIGH LOW COM
QC5 QC4
QC3
KZ
KL
07 09 08 0L0
ALO
R13 C8 R11 Q1
Q3
D2
AL2
DCR QCR
QC1
C
RL
01
G1
G2
Z1
A7 R9 AB A15
C4
C9
C0
QIL Z2 06 04
U1
C3
R4 RL4
JWZ
C7
D5 D3
R3 R5 R6
R2
JW5
QCB
Y
R W2 Y C W3 W3 W2 W2 C
JW4
P2
JW3
P4
P1
W2 W3
Y2 Y1
Y DH
G C R
SSTZ-8
P3
SDL
24V
AC/R
3AMP
CDM/C
F1
STD DEHUM
Table 3 – Color Coding for Indoor Fan Motor Leads
Black = High Speed
Orange = Med-High Speed
Red = Med Speed
Pink = Med-Low Speed
Blue = Low Speed
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.