Honeywell 7800 Series Manual page 43

TABLE 9—SEQUENCE AND STATUS HOLD MESSAGES (Continued)
NOTE: Normal sequences are in BOLD type, while abnormal sequences are not in bold type.
Sequence
INITIATE HOLD: AC
(AC Frequency)
INITIATE HOLD: AC
(Low Line Voltage)
STANDBY The VFD indicates
the burner status, STANDBY.
STANDBY HOLD: F/G
(Flame Detected)
STANDBY HOLD: T20
(Preignition ILK)
PURGE HOLD: T19
(High Fire Switch)
PURGE DELAY: T19
(High Fire Jumprd)
PURGE mm:ss
PURGE HOLD: TEST
(Run/Test Switch)
PURGE HOLD: T18
(Low Fire Jumprd)
PURGE HOLD: F/G
(Flame Detected)
PURGE HOLD: T18
(Low Fire Switch)
Message
The VFD indicates the burner status, INITIATE, and that line frequency is faster
than the expected value. The burner sequence will not advance into STANDBY
until the line frequency returns to the proper value (perhaps caused by using a
50 Hz device on a 60 Hz line).
The VFD indicates the burner status, INITIATE, and that low line voltage has
occurred. The burner sequence will not advance into STANDBY until the line
voltage is at a sufficient level for proper operating parameters.
The RM7838B will be in STANDBY after INITIATE and the burner switch is
open or by opening the burner switch any time in the operational sequence. The
burner sequence will not advance from STANDBY to PURGE until the Burner
Switch is closed. If an Expanded Annunciator is connected, the display messages
are enhanced.
The VFD indicates the burner status, STANDBY, and that a flame is detected.
The Burner Switch is closed for burner operation, but the burner sequence will
not advance to purge because a flame is detected as being present. The sequence
will not advance to purge until the flame signal clears. If the flame signal does
not clear within 40 seconds, the RM7838B will lockout.
The VFD indicates the burner status, STANDBY, and that the Preignition
Interlock is not closed. The Burner Switch is closed to start burner operation, but
the burner sequence will not advance to purge until the Preignition Interlock
proves closed. If this time exceeds a 30 second hold, the RM7838B will lockout.
The Preignition Interlock must also close within five seconds after the Stop
Switch is pushed.
The VFD indicates the burner status, PURGE, and that the High Purge Rate
Switch is not closed. The firing rate motor is driving to its PURGE rate position.
If this time exceeds four minutes and 15 seconds, the RM7838B will lockout.
The VFD indicates the burner status, PURGE, and that the High Fire Switch is
jumpered. The High Purge Rate Switch is bypassed, welded or otherwise
prematurely closed. The system will automatically add 30 seconds to the purge
timing to allow the firing rate motor additional drive time to reach or near the
open damper position before starting the PURGE sequence.
The VFD indicates the burner status, PURGE, which is the period of time before
the ignition period when the blower motor is running. The timing of the PURGE
period is selectable. PURGE is counted in minutes and seconds.
The VFD displays the burner status, PURGE, 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 VFD indicates the burner status, PURGE, 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 be near the closed damper position before
starting the ignition sequence.
The VFD indicates the burner status, PURGE, and that a flame is detected. The
burner sequence will not advance through PURGE 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 RM7838B will lockout.
The VFD indicates the burner status, PURGE, 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 two minutes and 15 seconds, the RM7838B
will lockout.
43
RM7838B
TROUBLESHOOTING
(continued)
65-0120—1