RT-SVF69C-EN
11
Sequence of Operation
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 in conjunction with the Variable Speed
Module (VSM) will provide capability to control of a
modulating eFlex™ compressor, and two multispeed
outdoor motors (ODM).
•
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 modulating eFlex
compressor starting with the minimum compressor motor
speed and runs through a start-up sequence for that
compressor, provided the low pressure control (LPC4),
high pressure control (HPC3), and the discharge line
thermostat (DLT3) are closed. When the eFlex compressor
and the outdoor fan motor are energized, they adjust
motor speeds in order to maintain the zone temperature
(Single Zone VAV) to /-0.5°F or Supply Air
Temperature (Multi Zone VAV) to within ±1°F of the sensor
setpoint at the sensed location. If the modulating
compressor at its maximum capacity cannot satisfy the
cooling requirement, the RTRM energizes the first fixed
speed compressor, provided the low pressure control
(LPC1), the high pressure control (HPC1), and the
discharge line thermostat (DLT1) are closed, while
simultaneously reducing the modulating compressor
motor speed to allow a smooth transition in system
capacity. When the fixed speed compressor is energized,
the ReliaTel control starts to maintain the zone
temperature (Single Zone VAV) to /-0.5°F or Supply
Air Temperature (Multi Zone VAV) to within ±1°F of the
sensor setpoint at the sensed location by modulating the
eFlex compressor speed and both ODM. If the first two
compressors cannot satisfy the load, the second fixed
speed compressor is energized in addition to the first fixed
speed compressor, provided the low pressure control
(LPC1), the high pressure control (HPC2), and the
discharge line thermostat (DLT2) are closed.
Simultaneously, the modulating compressor speed is
reduced for a smooth transition to the higher system
capacity. When the third compressor is energized, the
ReliaTel control starts to maintain the zone temperature
(Single Zone VAV) to /-0.5°F or Supply Air
Temperature (Multi Zone VAV) to /-1°F of the
sensor setpoint at the sensed location by modulating the
eFlex compressor motor speed and both ODM.
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 modulating 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 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