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RT-SVX26R-EN
Sequence of Operation
The ReliaTel Controls is a microelectronic control feature,
which provides operating function that is significantly
different than conventional electro-mechanical units. The
master module is the ReliaTel Refrigeration Module
(RTRM).
ReliaTel Controls
•
The master module is the ReliaTel Refrigeration
Module (RTRM).
•
The RTRM provides compressor anti-short cycle
timing functions through minimum “Off” and “On”
timing to increase reliability, performance and to
maximize unit efficiency.
•
Upon power initialization, the RTRM performs self-
diagnostic checks to insure that all internal controls are
functioning. It checks the configuration parameters
against the components connected to the system.
•
The LED located on the RTRM module is turned "On"
within one second after power-up if all internal
operations are okay.
•
The RTRM will provide capability to control of a multi-
speed indoor motor (IDM).
•
The ReliaTel Options Module (RTOM) is utilized in
conjunction with the RTRM for control of a variable
speed indoor motor (IDM) and optional accessories.
•
All units employ a Phase Monitor to ensure proper
power supply connection of phases for compressor
operation. If the monitor senses incorrect phase
connection (phase reversal), a loss of phase, or large
voltage imbalance between phases, all unit operation
will be prevented until the condition is corrected. The
Phase Monitor has green (Ok) and red (Phase Fault)
status LEDs on the face of the monitor. All units are
functional tested to ensure correct factory wiring. A red
status LED is an indication of a serious problem that
can only be resolved by isolating and repairing the
Supply Power fault.
ReliaTel Control Cooling without an
Economizer
When the system switch is set to the “Cool” position and
the zone temperature rises above the cooling setpoint
controlband, the RTRM energizes the first stage
compressor provided the low pressure control (LPC1),
high pressure control (HPC1), and the discharge line
thermostat (DLT1) are closed. When the first stage
compressor and the outdoor fan motor are energized, they
maintain the zone temperature to within ±2°F of the sensor
setpoint at the sensed location. If the first stage of cooling
cannot satisfy the cooling requirement, the RTRM
energizes the second stage compressor provided the low
pressure control (LPC2), the high pressure control (HPC2),
and the discharge line thermostat (DLT2) are closed. When
the second stage compressor is energized it starts to
maintain the zone temperature to within ±2°F of the sensor
setpoint at the sensed location.
ReliaTel Control Evaporator Fan
Operation
With the indoor fan in “Auto” mode, the RTRM energizes
the indoor fan motor for approximately 1 second after
energizing the first stage compressor in the cooling mode.
In the heating mode, the RTRM energizes the indoor fan
motor approximately 45 seconds after gas ignition (gas
heat unit) or 1 second before energizing electric heat
(electric heat unit). With the indoor fan in "On" mode, the
RTRM keeps the indoor fan energized for continuous fan
motor operation. When the unit is equipped with the
optional clogged filter switch, wired to the ReliaTel Options
Module (RTOM), the RTRM produces an analog signal
output if the clogged filter switch (CFS) closes for two
minutes after a request for fan operation. When the system
is connected to a remote panel, the “SERVICE” LED will be
turned on when this failure occurs.
Drain Pan Condensate Overflow Switch
(Optional)
This input incorporates the Condensate Overflow Switch
(COF) mounted on the drain pan and the ReliaTel Options
Module (RTOM). When the condensate level reaches the
trip point for 6 continuous seconds, the RTOM will shut
down all unit function until the overflow condition has
cleared. The unit will return to normal operation after 6
continuous seconds with the COF in a non-tripped
condition. If the condensate level causes the unit to
shutdown more than 2 times in a 3 day period, the unit will
be locked-out of operation. A manual reset of the
diagnostic system through the Zone Sensor or Building
Automation System (BAS) will be required. Cycling unit
power will also clear the fault.
Low Ambient Operation
During low ambient operation, outside air temperature
below 40°F, the RTRM will cycle the compressor and
outdoor fan motor “Off” for approximately 3 minutes after
every 10 minutes of accumulated compressor run time.
The indoor fan motor (IDM) will continue to operate during
this evaporator defrost cycle (EDC) and the compressor
and outdoor fan will return to normal operation once the
defrost cycle has terminated and the compressor “Off”
time delay has been satisfied.
ReliaTel Control Cooling with
an Economizer
The economizer is utilized to control the zone temperature
providing the outside air conditions are suitable. Outside
air is drawn into the unit through modulating dampers.
When cooling is required and economizing is possible, the
RTRM sends the cooling request to the unit economizer
