Data Aire gForce Ultra - Remote Heat Exchangers; High Pressure Cutout Switch; Low Pressure Cutout Switch; Liquid Line Solenoid Valve

gForce Ultra IOM
85
Remote Heat Exchangers
Most of the controls on remote condensers, condensing units or fluid coolers consist of basic
electromechanical type components. Remote heat exchangers have a separate User Manual which
gives complete details on adjusting thermostat settings, etc. Also refer to section 3.6 Heat Exchanger
Auxiliary Control Wiring.
High Pressure Cutout Switch
Each refrigerant circuit is protected by a high-pressure cutout switch with manual reset button. The
switch is typically located in the evaporator near the compressor. The high-pressure switch rating is:
Table 23 High Pressure Cutout Switch Setting
R-410A Refrigerant
Setting
Cut-out (Open)
575 PSI (3965 kPa)
Cut-in (Close)
Manual Reset
Low Pressure Cutout Switch
Each refrigerant circuit has a low-pressure cutout switch which features SPST open-low switch action
and automatic reset. The switch is typically located in the evaporator near the compressor. The low-
pressure switch rating is:
Table 24 Low Pressure Cutout Switch Setting
R-410A Refrigerant
Setting
Cut-out (Open)
50 PSI (345 kPa)
Cut-in (Close)
90 PSI (621 kPa)
Liquid Line Solenoid Valve
Liquid line solenoid valve(s) (LLVS) are a standard feature on this unit. The LLSV are direct acting, NC
(normally closed; i.e. closed when de-energized) solenoid operated valve(s). This has the advantage
that the valve is closed when the system is not running and when the solenoid valve is not energized.
For this reason, an electrical power failure does not lead to any problems with the refrigeration system.
The primary purpose of a solenoid valve in a refrigerant liquid line is to helps prevent refrigerant
migration
(i.e., flow into the evaporator) during the OFF cycle.
Energy Saver Cooling (Optional)
In colder climates, the evaporator will often be equipped with an additional free cooling coil to take
advantage of the colder ambient temperatures. When incoming fluid falls below the set point of a water-
sensing thermostat in the evaporator (typically about 50°F or 10C), energy saver cooling becomes
available.
Systems with an Energy Saver Coil should have at least one fluid-sensing thermostat on the fluid cooler
set lower to take advantage of colder ambient temperatures. The desired fluid temperature for energy
saver cooling is 45°F (7.2C). Field adjustment of fluid-sensing thermostats is not unusual.