Variable Capacity Compressor Controller; Table 22 - Demand Signal Vs. Compressor Capacity Modulation; Figure 28 - Variable Capacity Compressor Controller - AAON RN SERIES Installation Operation & Maintenance

Variable Capacity Compressor
Controller
Units with variable
compressors may include the following
compressor controller. The following is an
explanation of
troubleshooting alert flash codes of the
controller. For more information on the
compressor controller, see Emerson Climate
Bulletin AE8-1328.
Figure 28 - Variable Capacity Compressor
Controller
Note: When using field controls any
variable capacity compressors should run at
100% for 1 minute when starting.
WARNING
To avoid damaging the Compressor
Controller do not connect wires to
terminals C3, C4, T3, T4, T5, or T6.

Table 22 - Demand Signal vs. Compressor Capacity Modulation

Demand
Loaded %
Signal (VDC)
1.00
1.44
3.00
4.20
5.00 100%
capacity scroll
the terminals and
Unloaded %
Off Off
10% 90%
50% 50%
80% 20%
0%
Low Voltage Terminals
24COM Module Common
24VAC Module Power
Demand Input – & +
C1 & C2
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
Pressure Output – & +
P5 & P6
T1 & T2 Discharge Temperature Sensor
High Voltage Terminals
A1 & A2 Alarm Relay Out
M1 & M2 Contractor
L1 Control Voltage N
L2 Control Voltage L
U1 & U2 Digital Unloader Solenoid
V1 & V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an on/off
pattern according to the capacity demand
signal of the system. The following table
shows the linear relationship between the
demand signal and compressor capacity
modulation. The compressor controller
protects the compressor
discharge temperature. Refer to Appendix B
for the relationship between thermistor
temperature readings and resistance values.
Time
Time Loaded
Unloaded
Off
1.5 sec 13.5 sec
7.5 sec 7.5 sec
12 sec 3 sec
15 sec 0 sec
against high
% Compressor
Capacity
Off 0%
10%
50%
80%
100%
89