Section 4. Wiring
White
AC SYSTEMS
R
G
C
W1
B
Y
R
G
B/C
Y
W
Brown
24 V AC HO T
FA N
24 V AC
Common
COOLING
HEA T
Thermostat
Air Handler Outdoor
Unit
3.11 Sequence of Operation
Cooling (cooling only)
When the thermostat calls for cooling, the circuit from R to G is
completed. The blower motor is energized directly by the 24VAC
signal from the thermostat.
The circuit from R to Y is also completed, energizing the compressor
contactor of the outdoor unit. The contactor will close and start the
compressor and condenser fan motor.
Heating (electric heat only)
Note: The thermostat must be setup to bring the blower on when the
electric heat is energized.
When the thermostat calls for heating, the circuit from R to G is
completed and the blower motor is energized directly by the 24VAC
signal from the thermostat. The circuit from R to W is completed
energizing the heating contactor(s).
3.12 Operational And Checkout Procedures
To obtain proper performance, all units must be operated and charge
adjustments made in accordance with procedures found in the
Service Facts document of the outdoor unit.
After installation has been completed, it is recommended that the
entire system be checked against the following list:
[ ] 1. Be sure unit suspension (if used) is secure and there are
no tools or loose debris in, around or on top of the unit.
[ ] 2. Properly insulate suction lines and fittings.
[ ] 3. Properly secure and isolate all refrigerant lines.
[ ] 4. Verify that all electrical connections are tight.
[ ] 5. Check all duct outlets; they must be open and unrestricted.
[ ] 6. Check drain lines and be sure all joints are tight.
[ ] 7. Be sure the return air filter is installed.
[ ] 8. Operate complete system in each mode to verify proper
performance. Verify operation of supplementary electric heater.
7
3.13 Maintenance
The system air filter(s) should be inspected, cleaned or replaced at
least monthly. Make certain that the access panels are replaced and
secured properly before placing the unit back in operation. This
product is designed for dependable service; however, periodic
maintenance should be scheduled and conducted by trained
professional service personnel. This service should be conducted at
least annually, and should include testing and inspection of electrical
and refrigerant components. The heat transfer surface should be
cleaned. The blower motor is permanently lubricated for normal
operating conditions.
Table 1 Superheat Charging Chart
Outdoor
Temp(oF)
Indoor Temperature(oF) Dry Bulb/Wet Bulb
95/79
90/75
85/71
80/67
75/63
70/58
Superheat (°F)
115
23
16
7
5
5
5
110
24
17
9
5
5
5
105
26
19
11
6
5
5
100
27
21
13
7
5
5
95
29
23
16
8
5
5
90
30
25
18
12
6
5
85
32
26
20
16
9
5
80
34
28
22
17
11
5
75
35
30
24
19
13
6
70
37
32
26
21
16
10
65
38
34
29
24
19
13
60
40
36
31
27
22
17
55
41
37
33
29
25
21
Note: Chart is based on 400 CFM/Ton indoor airflow and 50%
relative humidity. If indoor relative humidity is above 70% or
below 20%. use indoor wet bulb temperature only. Airflow range
is 375 to 425 CFM/Ton.
This air handler comes with a factory-installed piston metering
device. A TXV may be required to achieve minimum efficiency
ratings or for long refrigerant line set applications. Reference AHRI
for system combination ratings.
Charge the system by superheat when using a piston. Reference the
outdoor unit installation guide to charge the system by subcooling
when using a TXV.