Laars NTH1000, Installation And Operation Instructions Manual

Page: 121 / 140

NeoTherm LC Boilers and Water Heaters Page 117
During the Initiate Period:
• All of the checks made under Synchronization,
plus:
• Locks out if A/C line power errors occur.
• Locks out if four-minute Initiate period has
been exceeded.
During the Standby Period:
• All of the checks made under Synchronization,
plus:
• Locks out if the Flame signal is present after
240 seconds.
• Locks out if the Preignition Interlock is open
for more than 30 seconds.
• Locks out if the Interlock Start check feature
is enabled and the Interlock String (including
the Airflow Switch) is closed for 120 seconds
with the controller closed, perhaps indicating a
jumpered or welded Interlock.
• Locks out if the Main Valve terminal is
energized.
• Locks out if an internal system fault occurs.
During the Prepurge Period:
• All of the checks made under Synchronization,
plus:
• Locks out if the Preignition Interlock opens
anytime during the Prepurge period.
• Locks out if the Flame signal is detected for
more than 10 seconds during Prepurge.
• Locks out if the Light Off Rate Fan RPM or
Low Fire Switch is not reached within four
minutes and fifteen seconds after the blower
is commanded to drive to the light off rate fan
RPM at the end of Prepurge.
• Locks out if the Main Valve terminal is
energized.
• Locks out if an internal system fault occurs.
During the Pre-Ignition Time:
• All of the checks made under Synchronization,
plus:
• Locks out if the Main Valve terminal is
energized.
During the Main Flame Establishing Period
(MFEP):
• All of the checks made under Synchronization,
plus:
• Locks out if no flame is present at the end of
the appropriate number of ignition retries.
• Locks out if an internal system fault occurs.
During the Run Period:
• All of the checks made under Synchronization,
plus:
• Locks out if an internal system fault occurs.
• Locks out if a safety-related parameter has
been changed, but the change has not been
verified and the controller has not been reset
using the button on the front of the control.
During the Postpurge Period.
• All of the checks made under Synchronization,
plus:
• Locks out if the Preignition Interlock does not
close in five seconds.
• Locks out if the Main Valve terminal is
energized.
• Locks out if an internal system fault occurs.
• Locks out if flame is sensed 240 seconds after
the Run period.