Specification Sheet

7800 SERIESS7800A2142 4Line LCD Keyboard Display Module
320011007 12
Sequence Status
PURGE HOLD:
T18 (Low Fire
Switch Jum-
pered)
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 addition-
al drive time to reach or near the closed damper position before starting the
ignition sequence.
PURGE HOLD:
F/G(Flame De-
tected)
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.
PURGE HOLD:
T18 (Low Fire
Switch)
The KDM indicates the burner status 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 relay module
locks out.
PURGE HOLD:
T7 (Running
Interlock)
The KDM indicates the burner status and that the Running Interlock is not
closed. The sequence does not advance to ignition until the Running Interlock
proves closed. If this time exceeds 30 seconds, the relay module locks out.
PILOT IGN
mm:ss
The KDM indicates the burner status, PILOT IGN, and the timing of the PILOT
IGN trial begins, in seconds. During this period, the relay module permits the
pilot valve to open and the pilot flame to establish.
If the relay module is in a PILOT HOLD status, the following conditions could exist:
PILOT HOLD:
TEST (Run/Test
Switch)
The KDM indicates the burner status, PILOT IGN, 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.
MAIN IGN mm:ss
The KDM indicates the burner status, MAIN IGN, and the timing of the MAIN
IGN trial begins, in seconds. During this period, the relay module permits the
main valve to open and the main flame to establish.
RUN
The KDM indicates the burner status, RUN, which is the period of time after the
Ignition Trials and before the operating controller setpoint is reached. During
this time, the burner is firing under control of the firing rate control.
If the relay module is in a RUN HOLD status, the following condition could exist:
RUN LOWFIRE:
TEST (Run/Test
Switch)
The KDM indicates the burner status and that the Run/Test Switch is in the
TEST position. Normal modulation or operation does not continue until the
Run/Test Switch is placed in the RUN position.
POSTPURGE
mm:ss
The KDM indicates the burner status, POSTPURGE, which is the period of time
after the RUN period when the blower motor continues to run. The timing of the
POSTPURGE period is fifteen seconds.
Waiting for con-
nection...
The KDM has power but is waiting to receive a signal from the relay module to
continue operation.
RESET/ALARM
TEST
The KDM indicates the burner status, RESET/ALARM TEST. This condition in-
dicates that the reset button is pressed. If it is held for more than four seconds,
the alarm output is energized. The alarm output is de-energized when the reset
button is released.
Additional Sequence Status Information When An Expanded Annunciator is Connected to the
Relay Module:
BURNER OFF: T6
(Burner Switch)
The KDM indicates the Burner Switch is not closed. The burner sequence does
not advance to PREPURGE until the Burner Switch closes.
STANDBY
The KDM indicates the burner status, STANDBY, and that the Operating Control
is not closed. The burner sequence does not advance to PREPURGE until the
Operating Control closes.
STANDBY HOLD:
T6 (EA Hold
Message)
The KDM indicates the burner status, STANDBY, and that a limit is not closed.
The burner sequence does not advance to PREPURGE until one or all limits
close downstream from the Operating Control.
STANDBY HOLD:
T6 (Circuit Fault)
The KDM indicates the burner status, STANDBY, and that the control input is not
closed. The burner sequence does not advance to PREPURGE until the control
input closes.
Table 3. Keyboard Display Module Sequence and Status Hold Messages .