Manual 2100-583G
Page
30 of 48
HIGH PRESSURE SWITCH
(Terminals HP1 & HP2) Circuit will be proved as
“closed” prior to energizing “A” or “CC” terminals.
If pressure switch opens, compressor will go into
soft lockout mode and compressor operation will be
terminated; green fault light illuminated. Logic control
will then go through 5-minute delay on break + random
start sequence. If no fault found on next run cycle,
compressor will continue operation. If fault reoccurs, hard
lockout occurs, and fault singal is sent to “L” terminal.
LOW PRESSURE SWITCH
(Terminals LP1 & LP2) Circuit will be proved as “closed”
prior to energizing “A” or “CC” terminals. The condition
of the LP terminals will then be ignored for the first
90 seconds after a demand for compressor operation.
Following this 90 second period, if pressure switch
opens, compressor will go into soft lockout mode and
compressor operation will be termininated; orange fault
light illuminated. The control board will then go through
a 5-minute delay on break + random start sequence. If no
fault found on next run cycle, compressor will continue
operation. If fault recoccurs, hard lockout occurs, and the
fault signal is sent to the “L” terminal.
FLOW SWITCH
(Terminals FS1 & FS2) Circuit will be proved as “closed”
prior to energizing “A” or “CC” terminals. If either flow
switch opens, compressor will go into soft lockout mode
and compressor operation will be terminated; red fault
light illuminated. Logic control will then go through
5-minute delay on break + random start sequence. If no
fault found on next run cycle, compressor will continue
operation. If fault reoccurs, hard lockout occurs, and fault
signal is sent to “L” terminal.
OVER & UNDER VOLTAGE PROTECTION
When an an under or over voltage condition exists, the
controller locks out the unit. When condition clears,
the controller automatically releases the unit to normal
operation and the compressor restarts after the random
start and anti-short cycle timings are met. The under &
over voltage protection starts at plus or minus 20% from
nominal voltage and returns to operation at plus or minus
10% from nominal voltage. All four (4) LED fault lights
will flash when an under or over voltage condition occurs.
NOTE:
The over voltage protection can be disabled by
removing the O/V jumper on the Geothermal Logic Control
Board.
INTELLIGENT RESET
The Geothermal Logic Control has an intelligent reset
feature after a safety control is activated. The controller
locks out the unit for 5 minutes, at the end of this period,
the controller checks to verify that all faults have been
cleared. If faults have been cleared, the controller restarts
the unit. If a second fault occurs, the controller will
lockout the unit until the control is reset by breaking “Y”
signal from thermostat. The last fault will be kept in
memory after a full lockout; this is only cleared by cycling
the unit power.
ALARM OUTPUT
The “L” terminal has 24 volts applied when a hard lockout
occurs. This can be used to drive a fault light or a low
voltage relay.
PRESSURE SERVICE PORTS
High and low pressure service ports are installed on all
units so the system operating pressures can be observed.
Pressure tables can be found later in this manual, and
also applied to the backside of the service door of the
unit. It is imperative to match the correct pressure table
to the unit by model number, and to the correct conditions
(temperature & flow rate). Also note that all pressure
tables are without the desuperheater operational.
This unit employs high-flow Coremax valves instead of the
typical Shrader type valves.
WARNING! Do NOT use a Schrader valve core removal
tool with these valves. Use of such a tool could result in
eye injuries or refrigerant burns!
To change a Coremax valve without first removing the
refrigerant, a special tool is required which can be obtained
at www.fastestinc.com/en/SCCA07H. See the replacement
parts manual for replacement core part numbers.
CHECKING REFRIGERANT CHARGE
QUANTITY
The correct R-410A charge is shown on the unit rating
plate. Reference Figure 18 – 22 to validate proper system
operation. However, it is recommended that if incorrect
charge is suspected, the system refrigerant charge be
reclaimed, evacuated, and charge to nameplate charge
quantity and type
The nameplate charge quantity is optimized for thermal
performance and efficiency throughout all modes of
operation.
SEQUENCE OF OPERATION
