Page 52
XP17
Unit Sequence of Operations
The following figures illustrated the overall unit sequence of operations along with various pressure switches and
temperature sensor operations. These figures also illustration the use of the compressor anti-short cycle function in
relations to unit Status, Fault and Lockout LED Codes system operations interaction.
On 24VAC power-up or heat pump control (A175) reset, the heat pump control shall perform the
following tasks:
1. Start the anti-short cycle delay.
2. Check temperature sensor and pressure switches at the start of cooling demand.
3. Air Conditioner control responds to the thermostat input after the anti-short cycle timer expires. If there
is no thermostat input, control goes to standby mode.
Heat Pump control receives
cooling input.
The heat pump control (A175) will apply:
1. 24VAC to compressor contactor output
Y1 OUT.
.
2. 24VAC to reversing valve output
O
terminal.
3. Output between 24 and 32 VDC on heat pump control's
ECM fan terminals
ECM Y1 FAN and ECM C
.
NOTE - If lower pressure switch is closed, system will ignore
for 90 seconds.
1. For low (S87) and high (S4) pressure switches sequence of operations, see figures 30 and 31.
2. For defrost calibration sequence of operations see figure 32.
3. For defrost sequence of operations see figure 32.
The outdoor fan control (A177) will:
Receive the DC voltage signal from the outdoor control (A175)
and converted the signal to a pulse width modulation (PWM)
signal. Jumper settings will determine fan PWM OUT fan speed.
NOTE — Refer to table 8 for jumper settings.
Room thermostat
calls for first stage?
Heat Pump control receives
heating input.
The heat pump control (A175) will apply:
1. 24VAC to compressor contactor output
Y1 OUT.
.
2. Output between 24 and 32 VDC on heat pump
control's ECM fan terminals
ECM Y1 FAN and
ECM C
.
NOTE - If lower pressure switch is closed, system will
ignore for 90 seconds.
Figure 29. One-Stage Cooling/Heating Sequence of Operation
Summary of Contents for iComfort SL18XC1 Series
Page 44: ...Page 44 XP17 Figure 21 Typical XP17 Wiring XP17 XX 230 06...
Page 45: ...Page 45 XP17 Factory Wiring Diagrams Figure 22 Typical Factory Wiring XP17 XX 230 01...
Page 46: ...Page 46 XP17 Figure 23 Typical Factory Wiring XP17 XX 230 02...
Page 47: ...Page 47 XP17 Figure 24 Typical Factory Wiring XP17 XX 230 03 and 05...
Page 48: ...Page 48 XP17 Figure 25 Typical Factory Wiring XP17 XX 230 06...
