Sequence of Operation
RT-SVX21AC-EN 59
If the burner fails to ignite, the ignition module will attempt
two retries before locking out. The green LED will indicate
a lock out by two fast flashes. An ignition lockout can be
reset by;
1. Opening for 3 seconds and
closing the
main power
disconnect switch.
2. Switching the “Mode” switch on the zone sensor to
“OFF” an
d then to the d
esired position.
3. Allowing the ignition control module to reset
automaticall
y after one hour. Refer to the “Ignition
Control Module Diagnostics” section for the LED
diagnostic definitions.
When the fan selection switch is
set to the “Auto” position,
the RTRM
energizes the indoor fan relay (F) coil
approximately 30 second after initiating the heating cycle
to start the indoor fan motor (IDM).
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.
Electromechanical Controls
These units are offered with two control options,
electromechanical and ReliaTel™ controls. The ReliaTel™
controls is a microelectronic control feature, which
provides operating functions that are significantly
different than conventional electromechanical units.
Electromechanical Control Cooling
without an Economizer
When the thermostat switch is set to the “Cool” position
and the zone temperature rises above the cooling setpoint,
the thermostat Y contacts close. The compressor
contactor (CC1) coil is energized provided the low
pressure control (LPC1), high pressure control (HPC1) and
discharge line thermostat (TDL 1) are closed. When the
(CC1) contacts close, compressor (CPR1) and the outdoor
fan motor (ODM) start. If the first stage of cooling can not
satisfy the cooling requirement, the thermostat closes Y2.
The compressor contactor (CC2) coil is energized provided
the low pressure control (LPC2), high pressure control
(HPC2) and discharge line thermostat (TDL 2) are closed.
When the (CC2) contacts close, compressor (CPR2)
starts.
Electromechanical Control Evaporator Fan
Operation (for Gas Units)
When the thermostat fan selection switch is set to the
“Auto” position, the Ignition Module (IGN) energizes the
indoor fan relay (F) approximately 1 second after
energizing the compressor contactor coil (CC1) in the
cooling mode. In the heating mode, the Ignition Module
(IGN) energizes the indoor fan relay (F) coil approximately
45 second after gas ignition. Closing indoor fan relay (F)
coil starts the indoor fan motor (IDM). The (IGN) de-
energizes the fan relay (F) approximately 80 seconds after
the cooling requirement has been satisfied to enhance unit
efficiency.
When the heating cycle is terminated, the indoor fan relay
(F) coil
is de-en
ergized approximately 90 seconds after the
heating requirement.
When the thermostat fan selection switch is set to the
“On” position, the (IGN) keeps the in
door fan relay coil (F)
energized for continuous fan motor operation.
Table 19. Ignition module diagnostics
Steady light
Module is powered up, but no active call for
heat.
Blinking at
continuous
steady rate
Active call for heat.
One blink
Loss of communication.
Two blinks
System lockout (failure to ignite, no spark, low/
no gas pressure, etc.)
Three blinks
Pressure switch (no vent air flow, bad CBM,
closed at initial call for heat). Auto reset.
Four blinks
High limit (excessive heat in combustion
chamber, low airflow). Auto reset.
Five blinks
Flame sensed and gas valve not energized or
flame sensed and no call for heat.
Six blinks
Flame rollout (CBM failure, incorrect gas
pressure, incorrect primary air). Requires
manual reset of the switch.
Seven blinks
ReliaTel™ module will communicate a heat fail
diagnostic back to the RTRM.
To Next Page
Loading...
