Honeywell 7800 Series Manual page 34

RM7840E,G,L,M
TROUBLESHOOTING
TABLE 6—SEQUENCE AND STATUS HOLD MESSAGES (Continued)
Sequence
STANDBY HOLD: T7 (Running Interlock)
PURGE
If the RM7840 is in a PURGE HOLD status, the following conditions could exist:
PURGE HOLD: T19 (High Fire Switch)
PURGE DELAY: T19 (High Fire Switch Jumpered)
PURGE HOLD: TEST (Run/Test Switch)
PURGE HOLD: T18 (Low Fire Switch Jumpered)
PURGE HOLD: F/G (Flame Detected)
PURGE HOLD: T18 (Low Fire Switch)
PURGE HOLD: T7 (Running Interlock)
Status
The LED indicates the burner status, POWER, and that the
Running Interlock is closed. If a demand is present for burner
operation, the burner sequence will not advance to
PREPURGE until the Running Interlock proves open. If this
time exceeds the 120 second hold, the RM7840 will lockout.
The LED indicates the burner status, POWER, which is the
period of time before Ignition period during which time the
blower motor is running. The timing of the PURGE period is
selectable.
The LED indicates the burner status, POWER, and that the
High Fire Switch is not closed. The firing rate motor is
driving to its PURGE rate position. If this time exceeds four
minutes and fifteen seconds, the RM7840 will lockout.
The LED indicates the burner status, POWER, and that the
High Fire Switch is jumpered. The High Fire Switch is
bypassed, welded or otherwise prematurely closed. The
system automatically adds 30 seconds to allow the firing rate
motor additional drive time to reach or near the open damper
position before starting the PURGE sequence.
The LED indicates the burner status, POWER, and that the
Run/Test Switch is in the TEST position. The sequence will
not continue until the Run/Test Switch is placed in the RUN
position.
The LED indicates the burner status, POWER, and that the
Low Fire Switch is jumpered. The Low Fire Switch is
bypassed, welded or otherwise prematurely closed. The
system will automatically add 30 seconds to allow the firing
rate motor additional drive time to reach or near the closed
damper position before starting the ignition sequence.
The LED indicates the burner status, POWER, FLAME, and
that a flame is detected. The burner sequence will not advance
through PREPURGE because a flame is detected as being
present. The sequence will hold waiting for the flame signal
to clear. If the time exceeds 30 seconds, the RM7840 will
lockout.
The LED indicates the burner status, POWER, and that the
Low Fire Switch is not closed. The firing rate motor is
driving to its Low Fire position in preparation for Ignition
Trials. If this time exceeds four minutes and fifteen seconds,
the RM7840 will lockout.
The LED indicates the burner status, POWER, and that the
Running Interlock is not closed. The sequence will not
advance to ignition until the Running Interlock proves
closed. If this time exceeds a 30 seconds, the RM7840G,M
will lockout.
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