General Information
10 RRU-SVX01F-EN
will be locked out, and a manual reset will be required to
restart the compressor.
Low Pressure Control ReliaTel Control
When the LPC is opened for one continuous second, the
compressor for that circuit is turned off immediately. The
compressor will not be allowed to restart for a minimum
of three minutes.
If four consecutive open conditions occur during the first
three minutes of operation, the compressor will be locked
out, and a manual reset will be required to restart the
compressor.
Dual Refrigerant Circuits
The two independent refrigerant circuits incorporate a
split face coil with thermal expansion valves (TXVs),
service pressure ports and refrigerant line filter driers as
standard. An area will be provided for replacement suction
line driers. Refrigerant circuit one (1
st
Stage) is equipped
with a factory installed and preset refrigerant capacity
control (RCC) to prevent evaporator coil temperatures
below approximately 38°F (109 lb suction).
High Pressure Control ReliaTel Control
The high pressure controls are wired in series between the
compressor outputs on the RTRM and the compressor
contactor coils. If the high pressure control switch opens,
the RTRM senses a lack of current while calling for cooling
and locks the compressor out.
On dual circuit units, if the high pressure control opens,
the compressor on the affected circuit is locked out. A
manual reset for the affected circuit is required.
Space RH Sensor (Optional) (4190-7019)
Field installed, wall mounted humidity sensor is used to
control activation of the hot gas reheat dehumidification
option. Humidity set points can be selected for relative
humidity levels between 40 percent and 60 percent.
Space Temperature Sensor (Optional)
(4190-1094)
Field installed, wall mounted temperature sensor with
adjustable cooling setpoint thumb wheel is used to control
space cooling and heating setpoints.
High Temperature Sensor (BAYFRST001A)
This sensor connects to the RTRM Emergency Stop Input
on the LTB and provides high limit “shutdown” of the unit.
The sensor is used to detect high temperatures due to fire
in the air conditioning or ventilation ducts. The sensor is
designed to mount directly to the sheet metal duct. Each
kit contains two sensors. The return air duct sensor is set
to open at 135°F. The supply air duct sensor is set to open
at 240°F. The control can be reset after the temperature has
been lowered approximately 25°F below the cutout
setpoint.
Outdoor Air Temperature and Relative
Humidity Sensor
This factory installed combination outdoor air sensor
located in the outdoor air hood is designed to sense both
outdoor air temperature and relative humidity for use by
the microprocessor controller to make required
ventilation, cooling, dehumidification and heating
decisions. Refer to “Sequence of Operation,” p. 19 for
detailed unit control and operational modes.
Control Input (Occupied/Unoccupied)
Terminals are provided on the terminal strip labeled
RRUTS for a field installed dry contact or switch closure to
put the unit in the Occupied or Unoccupied modes.
Hot Gas Reheat
This option shall consist of a hot-gas reheat coil located on
the leaving air side of the evaporator coil pre-piped and
circuited with a low pressure switch. Refer to “Sequence of
Operation,” p. 19 for detailed unit control and operational
modes.
100 Percent Outdoor Air Hood with
Damper and Filters
Factory installed and integrated 100 percent outdoor air
hood with damper controlled by a direct coupled actuator
and 2-in. [50.80-mm] permanent and washable aluminum
mesh filters accessible through a hinged access panel. The
unit is factory equipped with provisions to accept an
optional field installed 100 percent return air damper
controlled by a direct coupled actuator that is electrically
interlocked with the outdoor air damper to allow
100 percent return air recirculation in the Unoccupied
cooling mode. The standard damper tray is blocked off to
allow 100 percent outdoor airflow.
Modulating Direct Gas-Fired Burner
The unit will have fully modulating, high turndown direct
gas-fired heat. The heating section will have a direct gas-
fired burner constructed with a corrosion resistant
aluminum burner casting and stainless steel baffles. On an
initial call for heat, proper airflow must be verified
(sensed) through a dual action, factory preset high/low
burner differential air pressure switch prior to initiation of
the ignition process. After proving airflow, an electronic
ignition controller will begin a 30-second burner chamber
pre-purge. Following pre-purge a direct spark igniter will
ignite the fuel air mixture during a 15 second single-try
lock out ignition trial. The microprocessor based RRUCM
will enable gas to the burner through a direct acting, fully
modulating gas valve at a preprogrammed initial firing
rate for 45 seconds following successful ignition. At the
end of the 90-second total pre- and post-ignition cycles,
the gas burner will modulate to maintain required
temperature set points controlled by the RRUCM. After
one unsuccessful ignition attempt the entire heating
system will be locked out until manually reset at controller,
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