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Operating information
Hot surface ignition system
Hot Surface Igniter and Ignition Control Module The 399,999
- 750,000 Btu/hr models have one ignition module and one hot
surface igniter. The 990,000 - 2,070,000 Btu/hr models have two
ignition modules and two hot surface igniters.
Figure 7-10_Hot Surface Igniter
Figure 7-11_Hot Surface Ignition Control Module
Hot surface ignition control module
Ignition module lockout functions
The ignition module may lockout in either a hard-lockout
condition, requiring pushing of the RESET button to recycle
the control, or a soft-lockout condition which may recycle after
an approximate five-minute waiting period. This soft-lockout
condition is intended to allow self-correcting faults to correct
themselves and permit normal operation. A typical hard-lockout
fault is a flame failure condition. An ignition module that is in a
hard-lockout condition may only be reset by pushing the RESET
button next to the ignition control or the "RESET" button on
the diagnostic panel on the left end of the unit. Upon a flame
failure, the RESET button is only active after the control module
has completed its post-purge cycle. Turning main power "OFF"
and then "ON" or cycling the thermostat will not reset a hard-
lockout condition. Wait five seconds after turning on main
power before pushing the RESET button when the ignition
module is in a hard lockout. The ignition module will go into
a soft lockout if conditions of low air, low voltage or low hot
surface igniter current are present.
(continued)
A soft-lockout condition will operate the combustion air fans for
the post purge cycle and then the ignition module will pause for
approximately five minutes. At the end of this timed pause, the
ignition module will attempt a new trial for ignition sequence.
If the soft-lockout fault condition has subsided or has been
corrected at the end of the timed pause, main burner ignition
should be achieved with the resumption of the normal trial for
ignition sequence. If the control sensed fault is not corrected, the
ignition module will continue in the soft-lockout condition. If
the electronic thermostat opens during the soft-lockout period,
the ignition module will exit soft lockout and wait for a new call
for heat from the thermostat. A soft-lockout condition may also
be reset by manually cycling the thermostat or turning the main
power switch "OFF" and then "ON" after the control sensed
fault has been corrected.
Diagnostic status indication
The ignition module has an LED which indicates the status of
the safety circuits. A remote Ignition Module Status indicating
light is wired from the ignition module Status LED and mounted
on the front diagnostic panel. The flashing operation of this light
indicates the diagnostic status of the ignition control module.
The status LED, mounted on the ignition module flashes a code
sequence from the Ignition Module to indicate the status of the
ignition process. See FIG. 7-9 for the flashing diagnostic status
codes as signaled by the ignition module.
Installation & Operation Manual
51
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