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OPERATING SEQUENCE
Base Unit Controls
INDOOR (SUPPLY) FAN
If the thermostat fan operation is selected as Continuous,
then the indoor (supply) fan motor, which is remotely locat-
ed in the fan coil, runs continuously. If the thermostat fan op-
eration is selected as Automatic, then the indoor (supply)
fan motor runs when there is a call for Ventilation, Cooling,
or Heating. When thermostat is satisfied, then the indoor
(supply) fan motor stops. If there is a fan fault or a shutdown
condition in the fan coil, then the indoor (supply) fan will not
run if there is a call for ventilation, cooling, or heating and
the CHS unit will act as if it is not receiving a thermostat
demand.
COOLING,
UNIT
WITHOUT
TWO-STAGE UNITS
For two stage units, the CHS072*G/H and CHS091*M/N
use a two-stage Copeland
1. Third-party trademarks and logos are the property of their respective
owners.
CHS-072-121-01SI
10 Ton Heat Pump Dual Stage Charging Chart R-410A
(compressor full load, all condenser fans operating)
Fig. 17 — CHS121*G/H Charging Chart
ECONOMIZER
™1
Ultratech Scroll compressor in
Specifications subject to change without notice.
PN: 38AU000486 REV -
conjunction with a two-stage Comfort Alert Module (CADM).
The CHS121*G/H uses two compressors in tandem on a
single circuit in conjunction with two single-stage Comfort
Alert Modules (CADM).
CHS072*G/H and CHS091*M/N
When thermostat calls for Stage 1 Cooling, terminal Y1 is
energized. The CHS unit's Defrost Board (DFB) receives
this input at P2-5. DFB issues 24-v outputs at OF, P3-7
(RVS1) and P3-10 (COMP1). The OF output energizes out-
door fan relay (OFR); both outdoor fan motors start and run.
The output RVS1 energizes the reversing valve solenoid
(RVS); Reversing valve switches to Cooling position. Output
PL3-10 (COMP1, 24-v) is received at CADM terminal Y. If
anti-recycle time delay period has not expired, safety pres-
sure switches are open, and/or lockout alarms are active,
CADM relay will remain open, preventing compressor start.
—
When safety pressure switches are closed and CADM time
delay expires, the CADM relay closes, energizing Solenoid
Valve Relay SVR and compressor contactor C. SVR con-
tacts close, energizing the external liquid line solenoid
valve. Solenoid valve LLSV opens. Compressor contactor C
closes, energizing the compressor motor. Compressor
starts and system runs in Stage 1 Cooling mode.
21
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