Honeywell 7800 Series Installation Instructions Manual page 19

Run
1. The RM7838B,C releases the firing rate motor to
modulation (terminals 13 and 15 are closed)
(terminal 13 and 14 for
RM7838C1020/RM7838C2020).
2. The RM7838B,C is now in RUN and remains in RUN
until the controller input, terminal 6, opens (burner
control opens, Stop Switch is pushed, running
interlocks open, a limit opens, Run/Test is switched
to Test), indicating that the demand is satisfied or a
limit opened, or the Pilot Valve Hold (terminal 16) is
energized.
Pilot Valve Hold (except
RM7838C1020/RM7838C2020)
Pilot Valve Hold (switched line voltage input to terminal
16) allows the burner to be cycled back to Pilot from the
Run position without the need to do a complete burner
startup. This allows for batch loading in process
applications.
A shutter-type flame detection system is required to use
the Pilot Valve Hold function.
RM7838B,C 7800 SERIES RELAY MODULE
Pilot Valve Hold can also be used to hold the burner at the
end of PFEP if configuration jumper JR3 was clipped.
A switch closure to the RM7838B,C terminal 16 while in
the Run position initiates the Pilot Valve Hold:
1. RM7838B,C commands the firing rate motor to Low
Fire position.
2. Once Low Fire is proven (input to terminal 18
through Low Fire Switch), the pilot valve terminal is
energized.
3. Forty-five seconds later, the main valve terminal is
de-energized and the ignition terminal is energized
for ten seconds, then shut off.
4. Pilot valve, terminal 8, remains energized through-
out Pilot Valve Hold.
5. RM7838B,C remains in Hold as long as a Pilot Valve
Hold input is present on terminal 16.
6. Opening the Pilot Valve Hold input to terminal 16
puts the RM7838B,C ready to initiate MFEP.
The RM7838B,C goes into safety shutdown and sounds
the Alarm if flame is lost at any time during this sequence.
NOTE: A Shutter Check Detection System must be in
place to use the Pilot Valve Hold function. Fault
46 occurs along with safety shutdown.
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