Specifications

Page 23
J-Ignition (Burner) Control A3
Ignition control is factory set and is not adjustable. The control
makes three attempts at ignition and then locks out the sys
tem if ignition is not obtained after the third trial. Reset after
lockout requires only breaking and remaking thermostat de
mand. The control shuts off gas flow immediately in the event
of a gas or power failure. Upon restoration of gas and power,
the control will restart the ignition sequence and continue until
flame is established or system locks out.
DANGER
Shock hazard. Spark related components contain
high voltage. Disconnect power before servicing.
For proper unit operation, electrodes must be positioned cor
rectly in the flame and must be gapped correctly.
WARNING
The ignition control is not field repairable. Unsafe
operation will result.
K-Spark Electrode/Flame Sensor Gap
The electrode assembly can be removed for inspection by re
moving two screws securing the electrode assembly and slid
ing it out of unit.
Spark gap may be checked with appropriately sized twist drills
or feeler gauges. Disconnect power to the unit and remove
electrode assembly. The gap should be between 0.094" and
0.156". See figure 25.
SPARK ELECTRODE and FLAME SENSOR GAP
FIGURE 25
1/8" + 1/32"
SENSOR/ELECTRODE GAP
L-Flame Sensing
Flame current is an electrical current which passes from the
ignition control through the sensor electrode during unit op
eration. The current passes from the sensor through the
flame to ground electrode to complete a safety circuit. The
minimum flame current necessary to keep the ignitor from
lockout is 5 microamps. The electrodes should be located so
the tips are at least 1/2" inside the flame envelope. Do not
bend electrodes. To measure flame current, follow the proce
dure below:
DANGER
Electrodes are not field adjustable. Any alter
ations to the electrode may create a hazardous
condition that can cause property damage or per
sonal injury.
1- Disconnect power to unit.
2- Remove lead from sensing electrode and install a
0-50DC microamp meter in series between the sens
ing electrode and the sensing lead.
3- Reconnect power and adjust thermostat for heating
demand.
4- When flame is established, meter reading should be
8 to 20 microamps. Do not bend electrodes.
5- Disconnect power to unit before disconnecting meter.
Make sure sensor wire is securely reconnected be
fore reconnecting power to unit.
NOTE-If the meter scale reads 0, the leads are reversed.
Disconnect power and reconnect leads for proper polarity.
M-Combustion Air Blower
The combustion air blower and prove switch are factory set
and are not field adjustable. However, operation should be
monitored to ensure proper operation. The combustion air
blower is used to draw fresh air into the combustion chamber
while simultaneously expelling exhaust gases. The blower
operates throughout the heating cycle. On a heating demand,
the combustion air blower immediately energizes but the igni
tion control circuit does not. Once the combustion air blower
is energized, the combustion air prove switch closes to ener
gize the ignition control. The ignition control then begins at
tempting ignition after 30-40 seconds.
If the combustion air blower does not reach full speed the
prove switch will not close and the ignition control will not en
ergize. The unit will remain locked out until the problem is
found and corrected.