Operating Instructions
Part No. 70476501ENR7
73
Troubleshooting Guide
Flame okay during TFI, no flame sense after TFI
1. Check electrode position and cleanliness.
2. Check high voltage wire.
3. Poor ground at burner.
4. Poor flame, check flame current.
Reset failure
1. Reset switch was pressed too long. Try to reset again.
2. Reset switch is shorted. Replace switch.
Proper Electrode Location
Proper location of the electrode assembly is important for
optimal system performance. The electrode assembly should be
located so that the tips are inside the flame envelope and about
1/2 inch (1.2 cm) above the base of the flame. Refer to Figure 41
.
Figure 41
Flame Current Measurement
Flame current is the current that passes through the flame from
sensor to ground. To measure flame current, connect a True
RMS or analog DC micro-ammeter to the FC+ and the FC-
terminals. The reading should be 1.0 micro-amps DC or higher.
If the meter reads negative or below “0” on the scale, the meter
leads are reversed. Re-connect leads with proper polarity.
Alternately, a Digital Voltmeter may be used to measure the DC
voltage between the FC+ and FC- terminals. Each micro-amp
of flame current produces 1.0 VDC, so a reading of 2.6 VDC
would equate to 2.6 micro-amps.
A good burner ground that matches the control ground is critical
for reliable flame sensing.
Ignition Control Operation for Non-CE
Models Through 3/10/13
Power Up
When power is applied to the ignition control, the control will
begin the ignition sequence within 1 – 3 seconds prepurge
waiting time.
Ignition Sequence
The control begins the ignition sequence after prepurge by
powering the ignitor and opening the gas valve. The ignitor will
remain on either until a flame is sensed or until a maximum
of ten (10) seconds(10 +0/-4 sec) has elapsed. If a flame is
established and lost during the 10 second period, the ignitor will
be powered up again in an attempt to re-ignite the gas.
If no flame is detected within the ten (10) second ignition
sequence, the control will terminate power to the gas valves,
ignitor, and enter lockout within 5 seconds.
Normal Operation
Once a flame has been established, the spark ignitor will stop
sparking and the control will continually monitor all inputs. If
the controller senses a loss of flame after flame is established,
the gas valve will remain energized and sparking will commence
within one second of the flame loss. If flame reattempt fails,
lockout will occur within 11 seconds of initial flame loss.
Termination of Flame
Normal flame termination occurs when the thermostat has
been satisfied, meaning there is no immediate need for more
heat. The thermostat will disconnect power from the ignition
control, which will cause the gas valve to close and the flame
to go out. After a short period of time, not less than 1 second,
the thermostat will cool down and close causing power to
be reapplied to the ignition control. When this occurs, the
Summary of Contents for LDR-900-S
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