Historical Information Index - Honeywell 7800 Series Product Data

Table 5. Keyboard Display Module Sequence and Status Hold Messages (Continued).

Sequence

PURGE HOLD: F/G

The KDM indicates the burner status and that a flame is detected. The burner sequence does not

(Flame Detected)

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

The KDM indicates the burner status and that the Low Fire Switch is not closed. The firing rate motor is

(Low Fire Switch)

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

The KDM indicates the burner status and that the Running Interlock is not closed. The sequence does

(Running Interlock)

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

The KDM indicates the burner status, PILOT IGN, and that the Run/Test Switch is in the TEST position.

(Run/Test Switch)

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

The KDM indicates the burner status and that the Run/Test Switch is in the TEST position. Normal

(Run/Test Switch)

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 connection... 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 indicates 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

The KDM indicates the Burner Switch is not closed. The burner sequence does not advance to

(Burner Switch)

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

The KDM indicates the burner status, STANDBY, and that a limit is not closed. The burner sequence

(EA Hold Message)

does not advance to PREPURGE until one or all limits close downstream from the Operating Control.

STANDBY HOLD: T6

The KDM indicates the burner status, STANDBY, and that the control input is not closed. The burner

(Circuit Fault)

sequence does not advance to PREPURGE until the control input closes.

The S7800 provides diagnostic information to aid the service

mechanic in obtaining information when troubleshooting the

system. See Table 6 for information on accessing historical

and diagnostic selectable messages. Information available in

the Diagnostic Information includes Device Type, Device

Suffix, Software Revision, Manufacturing Code, Flame

Amplifier Type, Flame Failure Response Time (FFRT),

Selectable Jumper Configuration Status, Run/Test Switch

Status and Terminal Status.

7800 SERIES S7800A KEYBOARD DISPLAY MODULE

Status

The S7800 displays historical information for the six most

recent lockouts. Each of the six lockout records retains the

cycle when the fault occurred, a fault code, a fault message,

and burner status when the fault occurred. See Table 6.

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