Sequence Of Operation - Honeywell 7800 Series Installation Instructions Manual

c. High Fire Switch fails to close within five minutes
after the firing rate motor is commanded to drive
to high fire position at start of purge
(EC/RM7850A).
d. Low Fire Switch fails to close within five minutes,
after firing rate motor is commanded to drive to
low fire position at end of purge (EC/RM7850A).
e. Airflow Switch Input does not close within 10
seconds.
f. If Airflow Switch is disabled, there is no jumper
between terminals 6 and 7.
g. Airflow Switch opens during PURGE.
h. Lockout Input opens during purge.
i. Ignition/pilot valve/intermittent pilot valve ter-
minal is energized.
j. Main valve terminal is energized.
k. Internal system fault.
l. Purge card is removed.
m. Purge card is defective.
4. PREIGNITION
a. Lockout Input opens during PREIGNITION.
b. Airflow Switch opens during PREIGNITION.
c. Preignition Interlock opens during PREIGNI-
TION.
d. Flame signal detected during PREIGNITION.
e. Ignition terminal is not energized.
f. Pilot valve/intermittent pilot valve terminal is
energized.
g. Main valve terminal is energized.
h. Internal system fault.
i. Purge card is removed.
j. Purge card is defective.
5. SAFETY 1 PERIOD
a. Lockout Input opens during SAFETY 1.
b. Airflow Switch opens during SAFETY 1.
c. Low Fire Switch opens (EC/RM7850A).
d. No flame is present at the end of SAFETY 1.
e. Ignition terminal is not energized.
f. Pilot valve/intermittent pilot valve terminal is not
energized.
g. Main valve terminal is energized.
h. Internal system fault.
i. Purge card is removed.
j. Purge card is defective.
6. PILOT STAB. PERIOD
a. Lockout Input opens during PILOT STAB.
b. Airflow Switch opens during PILOT STAB.
c. Low Fire Switch opens (EC/RM7850A).
d. No flame is present.
e. Ignition terminal is energized.
f. Pilot valve/intermittent pilot valve terminal is not
energized.
g. Main valve terminal is energized.
h. Internal system fault.
i. Purge card is removed.
j. Purge card is defective.
7. MAIN TRIAL PERIOD
a. Lockout Input opens during MAIN TRIAL.
b. irflow Switch opens during MAIN TRIAL.
c. Low Fire Switch opens (EC/RM7850A).
d. No flame is present.
e. Ignition terminal is energized.
f. Pilot valve/intermittent pilot valve terminal is not
energized.
EC7830A, RM7830A, EC7850A, RM7850A 7800 SERIES RELAY MODULES
g. Pilot valve is energized during MAIN TRIAL
h. Main valve terminal is not energized.
i.
j.
k. Purge card is defective.
8. RUN Period.
a. No flame is present.
b. Lockout Input opens.
c. Ignition/interrupted pilot valve terminal is ener-
d. Main valve terminal is not energized.
e. Internal system fault.
f.
g. urge card is defective.
h. Airflow Switch Input opens.
9. POSTPURGE Period.
a. Ignition/pilot valve/intermittent pilot valve ter-
b. Main valve terminal is energized.
c. Internal system fault.
d. Purge card is removed.
e. Purge card is defective.
OPERATION

Sequence of Operation

The relay modules have the operating sequences listed
below; see Fig. 3 and 4. The relay module LED provide
positive visual indication of the program sequence:
POWER, PILOT, FLAME, MAIN and ALARM.
Initiate
The relay module enters the INITIATE sequence when the
relay module is initially powered. The relay module can
also enter the INITIATE sequence if the relay module
verifies voltage fluctuations of +10/-15% or frequency
fluctuations of ±10% during any part of the operating
sequence. The INITIATE sequence lasts for two seconds
unless the voltage or frequency tolerances are not met.
When not met, a hold condition is initiated and displayed
on the optional KDM for at least five seconds; when met,
the INITIATE sequence restarts. If the condition is not
corrected and the hold condition exists for four minutes,
the relay module locks out. Causes for hold conditions in
the INITIATE sequence:
a. AC line dropout detection.
b. AC line noise that can prevent a sufficient
c. Low line voltage brownouts.
The INITIATE sequence also delays the burner motor
starter from being energized and de-energized from an
intermittent AC line input or control input.
Standby
The relay module is ready to start an operating sequence
when the operating control input determines a call for
heat is present. The burner switch, limits, operating limit
control and all microcomputer-monitored circuits must be
in the correct state for the relay module to continue into
the PURGE sequence.
15
stabilization.
Internal system fault.
Purge card is removed.
gized.
Purge card is removed.
minal is energized.
reading of the line voltage inputs.
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