Install Instructions

45
5 Electrical connections (continued)
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 Table 5D for the flashing diagnostic status
codes as signaled by the ignition module.
Figure 5-15_Hot surface ignition control module
Installation & Service Manual
Note: Flame current is typically 2 - 6 μA
Hot surface ignition system
Hot surface igniter and ignition control
module
This unit has one ignition module and one hot surface igniter.
Figure 5-14_Hot surface igniter
The igniter is extremely fragile, be very
careful when removing. A faulty or damaged
hot surface igniter MUST BE replaced with
a Lochinvar PLT3400 igniter. Do not use
general purpose field replacement igniters.
⚠ CAUTION
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.
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.