Principal Technical Features - Honeywell 7800 Series Manual

RM7895A,B,C,D

PRINCIPAL TECHNICAL FEATURES

The RM7895 provides all customary flame safeguard
functions while providing significant advancements in the
areas of safety, annunciation and system diagnostics.
SAFETY SHUTDOWN (LOCKOUT) OCCURS IF:
1. INITIATE PERIOD
a. Purge card is not installed or removed.
b. Purge card is bad.
c. Configuration jumpers have been changed (after
200 hours).
d. AC line power errors occurred, see Operation.
e. Four minute INITIATE period has been exceeded.
2. STANDBY PERIOD
a. Flame signal is present after 40 seconds.
b. Airflow switch check feature model is selected
and the airflow switch is closed for 120 seconds
with controller closed (RM7895B,D).
c. Ignition/pilot valve/intermittent pilot valve ter-
minal is energized.
d. Main valve terminal is energized.
e. Delayed main valve terminal is energized
(RM7895C,D).
f. Internal system fault occurred.
g. Purge card is not installed or removed.
h. Purge card is bad.
3. PREPURGE PERIOD
a. Airflow lockout feature is enabled and the air-
flow switch does not close after ten seconds or
within the specified purge card timing.
b. Flame signal is detected after 30 seconds.
c. Ignition/pilot valve/intermittent pilot valve ter-
minal is energized.
d. Main valve terminal is energized.
e. Delayed main valve terminal is energized
(RM7895C,D).
f. Internal system fault occurred.
g. Purge card is removed.
h. Purge card is bad.
Principal Technical Features
4. PILOT FLAME ESTABLISHING PERIOD (PFEP)
a. Airflow lockout feature is enabled and the air-
flow switch opens.
b. Ignition/pilot valve terminal is not energized.
c. No flame present at end of PFEP.
d. Main valve terminal is energized.
e. Delayed main valve terminal is energized
(RM7895C,D).
f. Internal system fault occurred.
g. Purge card is removed.
h. Purge card is bad.
5. MAIN FLAME ESTABLISHING PERIOD (MFEP)
(RM7895C,D)
a. Airflow lockout feature is enabled and the air-
flow switch opens.
b. Ignition terminal is energized.
c. Ignition/pilot valve terminal is not energized.
d. Main valve terminal is not energized.
e. Delayed main valve terminal is energized.
f. No flame present at end of MFEP.
g. Internal system fault occurred.
h. Purge card is removed.
i. Purge card is bad.
6. RUN PERIOD
a. No flame present.
b. Airflow lockout feature is enabled and the air-
flow switch opens.
c. Interrupted pilot valve terminal is energized
(RM7895C,D).
d. Main valve terminal is not energized.
e. Delayed main valve terminal is not energized
(RM7895C,D).
f. Internal system fault occurred.
g. Purge card is removed.
h. Purge card is bad.
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