Specifications

82
RG SERIES ENGINEERING GUIDE
Option: ThermaShield coated water-to-refrigerant heat exchanger,
water lines and refrigerant suction lines shall be insulated to prevent
condensation at low liquid temperatures below 50°F.
Option: AlpinePure hot gas bypass
The hot gas bypass (HGB) option is designed to limit the minimum
evaporating pressure in the cooling mode to prevent the air coil from
icing. The option shall consist of a hot gas bypass valve installed
in the discharge side of the compressor. The refrigerant control
shall proportionately bypass hot gas refrigerant to the air coil when
suction pressure falls below 115 psig thus limiting air coil freeze-up.
Optional AlpinePure hot gas reheat
An optional hot gas reheat coil shall be available to allow
dehumidification-only operation. The internal reheat system shall
be factory installed and include a high efficiency reheat coil located
downstream of the evaporator coil, a reclaim valve and integral
controls to allow heating, cooling and reheat/dehumidification modes.
The reheat coil shall be sized so that during reheat/dehumidification
mode the unit will produce neutral air (78 ±3°F DB @ 50-58% relative
humidity) with typical 80 DB/67 WB °F entering air and 90°F entering
water temperature. The reheat coil shall be sized to restrict airflow by
no more than 0.17 in wg at 350 feet per minute airflow velocity.
Three control options are available:
Room wall dehumidistat – An optional room wall
dehumidistat shall control the reheat mode thru a 24VAC
‘Hum’ input (On or Off). Setpoint and deadband shall be
determined by the dehumidistat.
Duct humidity sensor (FX10 only) – An optional duct
humidity sensor shall be installed. The FX10 control reads
the humidity from the sensor and determines operation mode.
Setpoint and deadband are internally set by the FX10 control
and shall be are adjustable. Continuous blower operation is
a requirement for this mode to accurately measure relative
humidity during the off cycle.
Room wall humidity sensor (FX10 only) - An optional wall
humidity sensor is installed. The FX10 control reads the
humidity from the sensor and determines operation mode.
Setpoint and dead band are internally set by the FX10 control
and are adjustable. Continuous blower operation is NOT
requirement for this mode.
Dehumidification set point (used only with a humidity
sensor) - The factory default set point for dehumidification is
52% this is field adjustable from 30% to 60%. In addition there
shall be a factory default differential of 5% field adjustable from
5% to 15%. The control will enable re-heat when the space
humidity rises above the set point plus the differential.
Reheat operation during periods of vacancy - The control
logic contains an unoccupied set point that can be used for
periods the unoccupied mode if desired. The factory default for
the set point is 60% and is adjustable from 30% to 60%. The
unoccupied setback must be enabled either through a building
automation system or with a user interface. Factory default for
unoccupied setback is off.
Space humidity high and low alarm limits (building
automation system only) - The control has a high and low
alarm limit that can be enumerated over a building automation
system. The factory default set point for these alarm limits is
0% for the low alarm and 100% for the high alarm limit. These
limits can be adjusted through a building automation system.
Blower Motor and Assembly
The blower shall be a direct drive centrifugal type with a dynamically
balanced wheel. The housing and wheel shall be designed for quiet
low outlet velocity operation. The blower housing shall be removable
from the unit without disconnecting the supply air ductwork for
servicing of the blower motor. The blower motor shall be isolated
from the housing by rubber grommets. The motor shall be
permanently lubricated and have thermostatic overload protection.
Option: PSC blower motor shall be a three-speed PSC type.
Option: 5-Speed ECM blower motor shall be a 5-speed ECM
type. The 5-speed ECM blower motor shall be soft starting, shall
maintain constant torque over its operating static range, and shall
provide 5 speed settings. The blower motor shall be isolated from
the housing by rubber grommets. The motor shall be permanently
lubricated and have thermostatic overload protection. 5-speed ECM
motors shall be long-life ball bearing type.
Option: Variable speed ECM blower motor shall be a variable
speed ECM type. The variable speed ECM blower motor shall be
soft starting, shall maintain constant cfm over its operating static
range, and shall provide 12 cfm settings. Variable speed ECM
motors shall be long-life ball bearing type.
Option: High static blower motors shall be available on certain
PSC and ECM models.
Electrical
A control box shall be located within the unit compressor
compartment and shall contain a 75VA transformer, 24 volt
activated, 2 pole compressor contactor, terminal block for
thermostat wiring and solid-state controller for complete unit
operation. Electromechanical operation WILL NOT be accepted.
Units shall be name-plated for use with time delay fuses or HACR
circuit breakers. Unit controls shall be 24 volt and provide heating
or cooling as required by the remote thermostat/sensor.
An Aurora microprocessor-based controller that interfaces with
a multi-stage electronic thermostat to monitor and control unit
operation shall be provided. The control shall provide operational
sequencing, blower speed control, high and low pressure switch
monitoring, freeze detection, condensate overflow sensing, lockout
mode control, LED status and fault indicators, fault memory, field
selectable options and accessory output. The control shall provide
fault retry three times before locking out to limit nuisance trips.
Engineering Guide Specifi cations cont.