Operating Instructions
74
Part No. 70476501ENR7
control must complete the same prepurge and ignition sequence
specified above.
Control Lockout
When the control locks out, the gas valve will be closed and all
requests for heat will be ignored. The lockout mode may only
be discontinued by interrupting power to the control or cycling
the thermostat. After this occurs, the control will restart with its
normal power up and ignition sequence.
Low Voltage Detection
The control will have capability for detection of a low voltage
input condition. If input voltage on power up is below 19.0VAC
+0.8VAC/-0.5VAC, the control will disable output to gas valve
control relay. If input voltage rises above 19.8VAC for at least
three (3) seconds, the control will then re-enable function of the
gas valve control relay and ignition sequence may begin. On
powerup, the control function must always be disabled if greater
than 19.8VAC.
Ignition Control Operation for CE
Models Through 3/10/13
Power Up
After 24VAC is applied to the ignition control pins 24V and
GND, the Diagnostic LED on the ignition control will turn
orange/yellow. If a fault is detected the ignition control will
enter Lockout Mode. If no faults are detected, the Diagnostic
LED will turn Green and the ignition control will enter Standby
Mode.
Standby Mode
While in Standby Mode, the ignition control will continually
monitor the system for faults. Once 24VAC is applied to
terminals TH and GND on the control, the ignition control will
enter Start Up Mode.
Start Up Mode
During Start Up Mode, the ignition control will monitor the
system for faults and begin the ignition sequence. If no faults are
present, the ignition control will begin the ignition sequence by
entering an 18 second waiting period. During this time the Green
LED on the ignition control will switch between Red and Green,
before maintaining a Green color.
After the waiting period, the ignition control will turn on the
igniter and gas valve. The igniter will remain on until a flame is
sensed, or up to 10 seconds.
Once a flame has been sensed the ignition control will stop
sparking, the gas valve will remain on and ignition control will
enter Run Mode.
If a flame is not sensed, the ignition control will then begin two
additional retrials for ignition. The ignition control will re-enter
the 18 seconds waiting period before the ignition control makes
another attempt at ignition. If the three attempts at ignition fail,
the ignition control will enter Lockout Mode.
Run Mode
While in Run Mode the ignition control leaves the gas valve on,
monitors the flame signal, and leaves the igniter off.
If a flame signal is lost during Run Mode, one additional retrial
for ignition will take place within one second. The ignition
control will restore the spark for approximately 10 seconds.
If the ignition re-attempt fails, the ignition control will enter
Lockout Mode.
The ignition control will remain in Run Mode until 24VAC is
removed from terminals TH and GND on the control.
Termination of Flame
The flame will go out when power is removed from ignition
control. The ignition control will turn off the gas valve and enter
Standby Mode.
Lockout Mode
When Lockout Mode is entered, the ignition control will remove
power to the gas valve, the igniter will turn off, the Lockout/
Reset Light will turn on, and the Diagnostic LED will display
the appropriate Error Code.
Lockout Manual Reset
Lockout Mode is cleared by pressing an external reset switch
for three seconds. The ignition control will clear all error codes
and enter Standby Mode. During Lockout Manual Reset, the
Diagnostic LED on the ignition control flashes red and orange,
and the Reset Light remains on until the ignition control is reset.
After the Reset Light turns off, stop pressing the switch. Holding
the reset for three seconds after lockout has been cleared will
cause a fault and result in entering Lockout Mode again.
System Tests
The following system tests are performed during normal
operation. System tests are performed at a minimum of every 24
hours.
Low Voltage Detection
If the voltage between terminals TH and GND on the control
is below 18.75VAC +/- 0.75VAC for more than 3 seconds the
Summary of Contents for GA120L
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