RM7888A 7800 SERIES RELAY MODULE
19 32-00214—01
OPERATION
The user of the RM7888A is responsible for
providing an effective purge that meets the
approval of the authority having jurisdiction for a
particular installation. Failure to provide an
effective purge can result in a fire or explosion
that can cause damage, serious injury or death.
Sequences of Operation
The RM7888A has five user selectable operating
sequences: Pilot—PV Return; Pilot—MV Lo Fire; Direct
Spark Ignition (DSI) Normal Operating Sequence; DSI
High/Low Stepfire Operating Sequence and DSI Off/On
Stepfire Operating Sequence. Each operating sequence
will be discussed in detail.
The user selects the appropriate control
sequence by clipping configuration jumpers.
Sequence selection must be done correctly.
Failure to select the sequence correctly can be
hazardous. Follow instructions in this
specification.
Selectable Site-Configurable
Jumpers
The RM7888A has five site-configurable jumper options
and three options that will result in a lockout, see Fig. 20
and Table 6. The site-configurable jumpers should be
clipped with side cutters and the resistor removed from
the Relay Module.
Fig. 20. Selectable site-configurable jumpers.
Table 6. Site-Configurable Jumper Options.
1 Each operating sequence is described individually in the Operation section of this specification. Read the appropriate
operating sequence section carefully before clipping jumpers. The sequence selection cannot be reversed.
Pilot Configuration Operating
Sequence
The Pilot Configuration Operating Sequence has two
distinct operating sequences that are entered from the
Standby/ Standby Purge states. The sequences are:
a. PV Return: allows the control to reestablish the
pilot and de-energize the main flame in response
to the system heating requirements.
b. MV Lo Fire: will not allow the pilot to be re-estab-
lished once RUN has been entered; the main
valve remains energized with Lo Fire being the
lowest firing rate allowed.
See Table 7 for the state names, the text that appears on
the S7800 Keyboard Display Module, and the purpose.
SELECTABLE CONFIGURATION JUMPERS
M7861A
Jumper
RM7888A ActionJ1 J2 J3
Intact Intact Intact Default, selects the Pilot Configuration Burner
Sequence, including the Pilot Relight Function.(PV
Return)
1
Intact Clipped Clipped
Selects DSI Normal Burner Sequence.
1
Clipped Intact Clipped
Selects DSI High/Low Stepfire Burner Sequence.
1
Clipped Clipped Intact
Selects DSI Off/On Stepfire Burner Sequence.
1
Intact Intact Clipped Selects Pilot Configuration Burner Sequence, but
excludes the Pilot Relight Function.(MV Lo Fire)
1
.
Intact Clipped Intact Illegal; will result in a lockout.
Clipped Intact Intact Illegal; will result in a lockout.
Clipped Clipped Clipped Illegal; will result in a lockout.
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