Reznor CAUA Users Manual - Manual (Page 8)

Form O-CAUA, Page 8
FIGURE 5 - Integrated Ignition
Control Module, P/N 195573
Control Status - Green LED
Steady ON Normal Operation, No call for heat
Fast Flash Normal Operation, Call for heat
1 Flash System Lockout, Failed to detect or sustain flame
2 Flashes Pressure Switch in Open Position
3 Flashes High Limit or Flame Rollout Switch Open
4 Flashes Pressure Switch is closed before venter is energized
Steady Off Internal Failure - Replace the ignition control module
Flame Status - Yellow LED
Steady On Flame is sensed
Slow Flash Weak Flame
Fast Flash Undesired Flame
Fan Delay to
OFF Switch (DIP
Switch Settings -
selected prior to
call for heat)
SW1 SW2 Fan Delay To OFF (seconds)
OFF OFF 120
OFF ON 90
ON OFF 160 (Factory Preset)
ON ON 45
Ignitor Connection
3.0 SERVICE - Control Location, Operation, and Service (cont'd)
1) Call for Heat - The heating/cooling system controller
calls for heat. The ignition system circuit board
checks to see that the limit switch is closed and
the pressure switch is open. If the limit switch is
open, the circuit board responds as defined in the
“Abnormal Heat Cycle, Limit Switch Operation”. If the
pressure switch is closed, the circuit board will do
four flashes on the green LED and wait indefinitely for
the pressure switch to open. If the pressure switch is
open, the circuit board proceeds to prepurge.
2) Prepurge - The circuit board energizes the venter
motor and waits for the pressure switch to close. If
the pressure switch does not close within 30 seconds
of the venter motor energizing, the circuit board will
do two flashes on the green LED. The circuit board
will leave the venter motor energized indefinitely as
long as the call for heat remains and the pressure
switch is open.
When the pressure switch is proven closed, the
circuit board begins the prepurge time. If flame is
present any time while in prepurge, the prepurge time
is restarted. If flame is present long enough to cause
lockout, the circuit board responds as defined in
“Fault Modes, Undesired Flame”.
The ignition system circuit board runs the venter
motor for a 20 second prepurge time, then proceeds
to the ignition trial period.
3) Ignition Trial Period - The ignition system circuit
board energizes the spark and main gas valve. The
venter remains energized. If flame is sensed during
the first 16 seconds, the spark is de-energized.
If flame has not been sensed during the first 16
seconds, the control de-energizes the spark output
and keeps the gas valve energized for an additional
one second flame proving period. If flame is not
present after the flame proving period, the control
de-energizes the gas valve and proceeds with ignition
re-tries as specified in “Abnormal Heat Cycle, Ignition
Retry”. If flame is present, the circuit board proceeds
to steady heat.
4) Steady Heat - Circuit board inputs are continuously
monitored to ensure limit and pressure switches
are closed, flame is established (sensor on both
burner sections), and the system controller call for
heat remains. When the call for heat is removed, the
ignition system circuit board de-energizes the gas
valve and begins postpurge timing.
5) Post Purge - The venter motor output remains on
for a 45 second postpurge period after the system
controller is satisfied.
Normal Heat Cycle Operating Sequence
Service: The direct spark integrated circuit board is polarity sensitive. If burners cycle
on and off, try switching the power supply leads. The supply connection made to "L1"
on the circuit board must be the "hot" wire.
The only replaceable component of the control module is the 3 amp Type ATC or ATO
fuse.
If it is determined that any of the components of the ignition system require replacing,
use only the factory-authorized replacement parts that are designed for this heater.
3.3 Service Procedures (cont'd)
3.3.2 Ignition System (cont'd)
Lights