RM7888A 7800 SERIES RELAY MODULE
9 32-00214—01
Table 5. Sequence Timing for Operation.
* STANDBY and RUN can be an infinite time period.
** PURGE will be determined by the system master controller.
*** RM7888A1001 and A1019 are 4 seconds; RM7888A1027 is 10 seconds.
PRINCIPAL TECHNICAL
FEATURES
The RM7888A provides 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. Configuration jumper was changed (after 200
hours).
b. AC line power errors, see Operation section.
c. Four minute INITIATE period is exceeded.
2. STANDBY Period
a. Flame signal is present after 240 seconds.
b. Pilot valve/1st stage main valve terminal is ener-
gized.
c. Main valve terminal is energized.
d. Internal system fault.
e. Flame detected during the last two seconds.
f. Limits Complete is not energized after 120 sec-
onds.
g. Hold @Low Fire Switch is not energized after
eight minutes of hold.
h. Flame Proven terminal energized.
i. Ignition terminal energized.
j. Configuration jumpers select is illegal (during
last two seconds).
3. PILOT FLAME ESTABLISHING Period (PFEP) (Pilot
Configuration)
a. Pilot/1st stage main valve terminal is not ener-
gized.
b. No flame is present at end of PFEP.
c. Internal system fault.
d. Main valve terminal is energized.
e. Limits Complete is not energized.
f. @Low Fire is not energized.
g. Ignition terminal is not energized for the first ten
seconds of PFEP.
h. Ignition terminal is energized after the first ten
seconds of PFEP.
i. Flame Proven terminal is energized for the first
ten seconds of PFEP.
j. Flame Proven terminal is not energized at the
end of PFEP.
k. Special Function 2 is not energized after eight
minutes (Pilot Configuration).
4. MAIN FLAME ESTABLISHING Period.
a. Pilot is not energized.
b. Pilot/1st stage main valve terminal is not ener-
gized.
c. Main valve terminal is not energized.
d. No flame present.
e. Internal system fault.
f. @Low Fire switch is not energized.
g. Ignition terminal is energized.
h. Flame Proven is not energized.
i. Limits Complete is not energized.
j. Special Function 2 is not energized.
k. Special Function 3 is not energized.
5. RUN Period
a. No flame present.
b. Flame Proven is not energized.
c. Internal system fault.
d. Ignition terminal is energized.
e. Pilot terminal is energized (Pilot configuration).
f. Pilot terminal/main valve first stage is not ener-
gized (DSI configuration).
g. Limits Complete is not energized.
h. Main valve is not energized.
6. Anytime the configuration jumpers are changed
while the RM7888A is powered.
7. PILOT RELIGHT
a. Limits Complete is de-energized.
b. Special Function 2 is not energized.
c. Special Function 3 is not energized.
d. Ignition, pilot, or main is not energized.
e. Low Fire is not energized.
f. Flame failure.
g. Ignition terminal not energized.
h. Flame Proven is not energized.
8. WAIT FOR LOW OFF FOR 5 SECONDS
a. Limits Complete is not energized.
b. Special Function 2 is not energized.
c. Flame failure.
d. Ignition energized.
e. Main energized.
f. Flame Proven not energized.
g. Pilot not energized.
9. DRIVE TO LOW
RM7888A
Sequence Initiate Standby Purge
Pilot Flame
Establishing Period
(PFEP)
Main Flame
Establishing
Period (MFEP) Pilot Relight Run
Pilot: PV
Return
10 seconds * ** 10 seconds 10 seconds 5 sec to
infinity
*
Pilot: MV Lo
Fire
10 seconds * ** 10 seconds 15 seconds — *
DSI Normal 10 seconds * ** *** — — *
DSI High/Low
Stepfire
10 seconds * ** *** — — *
DSI On/Off
Stepfire
10 seconds * ** *** — — *
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