Principle Technical Features - Honeywell 7800 Series Manual

The RM7840 provides all customary flame safeguard
functions while supplying 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. Preignition Interlock is open an accumulative
time of 30 seconds.
c. Interlock check feature is enabled and the Inter-
lock String (including airflow switch) is closed
for 120 seconds with controller closed.
d. Ignition/pilot valve/intermittent pilot valve ter-
minal is energized.
e. Main valve terminal is energized.
f. Internal system fault occurred.
g. Purge card is not installed or removed.
h. Purge card is bad.
3. PREPURGE Period
a. Preignition Interlock opens anytime during
PREPURGE period (RM7840E,L).
b. Flame signal is detected after first ten seconds
during PREPURGE (RM7840E,L).
c. High Fire Switch fails to close within four min-
utes and fifteen seconds after the firing rate
motor is commanded to drive to the high fire
position at the start of PREPURGE (RM7840E,L).
d. Low Fire Switch fails to close within four min-
utes and fifteen seconds after the firing rate
motor is commanded to drive to the low fire
position at the end of PREPURGE.
e. Running Interlock does not close within 30 sec-
onds (RM7840G,M).
f. Lockout Interlock does not close within 10 sec-
onds (RM7840E,L).
g. Lockout Interlock opens during PREPURGE
(RM7840E,L).
h. Ignition/pilot valve/intermittent pilot valve ter-
minal is energized.
Principal Technical Features
i. Main valve terminal is energized.
j. Internal system fault occurred.
k. Purge card is removed.
l. Purge card is bad.
4. PILOT FLAME ESTABLISHING Period (PFEP)
a. Low Fire Switch opens.
b. Lockout Interlock opens (RM7840E,L).
c. Ignition/pilot valve/intermittent pilot valve ter-
minal is not energized.
d. Early spark termination terminal is energized
after five seconds.
e. No flame is present at end of PFEP.
f. Main valve terminal is energized (RM7800G,M).
g. Internal system fault occurred.
h. Purge card is removed.
i. Purge card is bad.
5. MAIN FLAME ESTABLISHING Period (MFEP)
a. Low Fire Switch opens.
b. Lockout Interlock opens (RM7840E,L).
c. Ignition/pilot valve/intermittent pilot valve ter-
minal is not energized.
d. Main valve terminal is not energized.
e. No flame is present at end of MFEP.
f. Internal system fault occurred.
g. Purge card is removed.
h. Purge card is bad.
6. RUN Period
a. No flame is present.
b. Lockout Interlock opens (RM7840E,L).
c. Interrupted pilot valve terminal is energized
(RM7840G,M).
d. Main valve terminal is not energized.
e. Internal system fault occurred.
f. Purge card is removed.
g. Purge card is bad.
7. POSTPURGE Period
a. Preignition Interlock does not close in five sec-
onds and opens after five-second time period.
b. Ignition/pilot valve/intermittent pilot valve ter-
minal is energized.
c. Main valve terminal is energized.
d. Internal system fault occurred.
e. Purge card is removed.
f. Purge card is bad.
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RM7840E,G,L,M
PRINCIPAL TECHNICAL FEATURES
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