Honeywell S7800A Installation Manual page 13

Sequence
INITIATE mm:ss
If the relay module is in an INITIATE HOLD status, the following conditions could exist:
INITIATE HOLD:
(AC Frequency/Noise)
INITIATE HOLD:
(AC Line Dropout)
INITIATE HOLD:
(AC Frequency)
INITIATE HOLD:
(Low Line Voltage)
STANDBY
If the relay module is in a STANDBY HOLD status, the following conditions could exist:
STANDBY HOLD:
F/G (Flame Detected)
STANDBY HOLD: T20
(Pre-Ignition Interlock)
STANDBY HOLD: T7
(Lockout Interlock)
STANDBY HOLD: T7
(Running Interlock)
EC/RM7850
PURGE
If the relay module 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)
Table 5. Keyboard Display Module Sequence and Status Hold Messages.
The Keyboard Display Module (KDM) indicates the burner status, INITIATE, a stabilization period for
the relay module to check for any fluctuations in ac line voltage inputs or control inputs on power up or
during normal operation. The timing of the INITIATE period is either two seconds or ten seconds,
depending on the model, before entering STANDBY.
The KDM indicates the burner status and that it is waiting for excess line noise to clear up, which
prevents sufficient reading of the line voltage inputs. The burner sequence does not advance into
STANDBY until the excess line noise ceases or a line frequency error occurs; this is caused by using a
60 Hz device on a 50 Hz line, or vice versa on devices with a date code earlier than 9804, is corrected.
The KDM indicates the burner status and that ac line power has momentarily dropped out. The burner
sequence does not advance into STANDBY until the ac line voltage has stabilized throughout the
INITIATE sequence.
The KDM indicates the burner status and that line frequency is faster than the expected value. The
burner sequence does not advance into STANDBY until the line frequency returns to the proper value;
this is perhaps caused by using a 60 Hz device on a 50 Hz line for devices with a date code earlier
than 9804.
The KDM indicates the burner status and that low line voltage (10% lower than rated voltage) has
occurred. The burner sequence does not advance into STANDBY until the line voltage is at a sufficient
level for proper operating parameters.
The KDM indicates the burner status, STANDBY. The burner can be placed in STANDBY by opening
the burner switch or if the operating controller indicates its setpoint is satisfied. If a demand is present
for burner operation, the burner sequence does not advance from STANDBY to PURGE until the
recycle limits close. If an Expanded Annunciator is connected, the display messages are enhanced.
The KDM indicates the burner status and that a flame is detected. A demand is present for burner
operation. The sequence does not advance to PREPURGE until the flame signal clears. If the flame
signal does not clear within 40 seconds, the relay module locks out.
The KDM indicates the burner status and that the Pre-Ignition Interlock is not closed. A demand is
present for burner operation, but the burner sequence does not advance to PREPURGE until the Pre-
Ignition Interlock proves closed. If this time exceeds a 30 second hold, the relay module locks out.
The KDM indicates the burner status and that the Lockout Interlock is closed. A demand is present for
burner operation, but the burner sequence does not advance to PREPURGE until the Lockout
Interlock proves open. If this time exceeds the 120 second hold, the relay module locks out.
The KDM indicates the burner status and that the Running Interlock is closed. A demand is present for
burner operation, but the burner sequence does not advance to PREPURGE until the Running
Interlock proves open. If this time exceeds the 120 second hold, the relay module locks out.
The KDM indicates the burner status, PURGE, which is the period of time the blower motor is running
before the Ignition period. The timing of the PURGE period is selectable.
The KDM indicates the burner status 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 relay
module locks out.
The KDM indicates the burner status 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 KDM indicates the burner status and that the Run/Test Switch is in the TEST position. The
sequence does not continue until the Run/Test Switch is placed in the RUN position.
The KDM indicates the burner status and that the Low Fire Switch is jumpered. The Low 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 closed damper position before
starting the ignition sequence.
The KDM indicates the burner status and that a flame is detected. The burner sequence does not
advance through PREPURGE because a flame is detected as being present. The sequence holds
waiting for the flame signal to clear. If the time exceeds 30 seconds, the relay module locks out.
7800 SERIES S7800A KEYBOARD DISPLAY MODULE
Status
13 65-0090-6