36
OPERATING SEQUENCE

Base Unit Controls

Indoor (Supply) Fan —
The indoor fan contactor (IFC) is remotely located at the fan
coil or fan section. If the thermostatfan operation is selected
as Continuous, the IFC is energized and the indoor (supply)
fan motor runs continuously. If the thermostat fan operation
is selected as Automatic, the IFC will be energized on a call
for Cooling; indoor (supply) fan motor runs. When
thermostat call for Cooling is satisfied, the IFC is
de-energized and indoor (supply) fan motor stops.
Cooling, Unit WithoutEconomize r —
569J***A/B (Single Circuit)
On a thermostat call for Cooling, IFC will be energized
and indoor (supply) fan motor runs. Thermostat output Y1
is energized; terminal Y1 at 569J***A/B unit receives
24-v.24-v received at CADM1 terminal Y. If anti-recycle
time delay period has not expired, CADM1 relay will
remain open, de-energizing Solenoid Valve Relay (SVR)
and preventing compressor start. When safety pressure
switches are closed and CADM1 time delay expires,
CADM1 relay closes, SVR and compressorcontactor C
are energized; liquid line solenoid valve LLSV opens, all
outdoor fan motors start and Compressor starts.
As space cooling load is satisfied, thermostat out put Y1 is
de--energized,removing 24-v at 569J***A/B terminal Y1.
On Y1 opening, Compressor stops, all outdoor fan motors
stop and SVR relay is de-energized. Liquid line solenoid
valve is de-energizedand valve closes. CADM1 begins its
three-minuteanti-recycle time delay.
569J***D/E (TwoCircuit)
On a thermostat call for Cooling, IFC will be energized
and indoor (supply) fan motor runs. Thermostat output Y1
is energized; terminal Y1 at 569J***D/E unit receives
24-v.24-v received at CADM1 terminal Y. If anti-recycle
time delay period has not expired, CADM1 relay will
remain open, de-energizing Solenoid Valve Relay 1
(SVR1) and preventing compressor start. When safety
pressure switches are closed and CADM1 time delay
expires, CADM1 relay closes, SVR1 and compressor
contactor C1 are energized; liquid line solenoid va lve
LLSV1 opens, all outdoor fan motors start and Circuit 1
compressor starts.
On a thermostat calling for Stage 2 Cooling, thermostat
output Y2 is energized; terminal Y2 at 569J***D/E unit
receives 24-v. 24-v received at CADM2 terminal Y. If
anti-recycle time delay period has not expired, CADM2
relay will remain open, de-energizing Solenoid Valve
Relay 2 (SVR2) and preventing compressor start. When
safety pressure switches are closed and CADM2 time
delay expires, CADM2 relay closes, SVR2 and
compressor contactor C2 are energized; liquid line
solenoid valve LLSV2 opens and Circuit 2 compressor
starts.
As space cooling load is satisfied, thermostat outputs Y2
and Y1 are de--energized, removing 24-v at 569J***D/E
terminals Y2 and Y1. Circuit 2 compressor stops on Y2
opening; SVR2 is de-energized and LLSV2 closes.
CADM2 begins its three-minute anti-recycletime delay.
On Y1 opening, Circuit 1 compressor stops, all outdoor
fan motors stop and SVR1 relay is de-energized. Liquid
line solenoid valve LLSV1 is de-energized and valve
closes. CADM1 begins its three-minute anti-recycle time
delay.
All Units
If either the LowPressure Switch or High Pressure Switch
opens while thermostat output Y1 or Y2 remain energized,
the compressor contactor is de-energized, the compressor
stops and liquid line solenoid is de-energized (valve
closes). CADM initiates a TRIP event (cooling demand
sensedat CADM terminal Y but no current is measured at
T1, T2, T3 motor sensors); CADM relay opens and RED
LED is illuminated. TRIP condition maintains lockout of
compressor operation until CADM is manually reset.
Reset CADM by cycling unit main power.
Complete system shutdown may be caused by loss of
main power, open compressor internal overload, open
low-pressure or high-pressure switch, or a fault detected
by the CADM logic. Compressor operation without
cooling may indicate the compressor’s ASTP feature is
active; disconnect unit power and allow compressor to
cool. See Servicesection for further details.
Cooling, Unit With Economizer —
Refer to fan coil unit installation instructions and
economizer accessory installation instructions for
operating sequences when system is equipped with
accessoryeconomizer.
Heating—
Refer to fan coil unit installation instructions and accessory
heating device installation instructions for operating
sequences in heating mode.
569J