RM7800E,G,L,M; RM7840E,G,L,M 7800 SERIES RELAY MODULES
13 66-1085—3

Keyboard Display Module (VFD)

The Keyboard Display Module (see Fig. 5) is provided with the
RM7800 Relay Module (but is not required for operation) and
is an option for the RM7840 Relay Module. The first line of the
Vacuum Fluorescent Display (VFD) provides:
• Current status of the burner sequence (STANDBY,
PURGE, PILOT IGN, MAIN IGN, RUN and POSTPURGE).
• Timing information (PURGE, PILOT IGN, MAIN IGN and
POSTPURGE) in minutes and seconds.
• Hold information (PURGE HOLD: T19).
• Lockout information (Lockout, Fault Code, Message and
Sequence).
The extreme right side of the first line is either blank or shows
a small arrow pointing to the second line followed by a
two-letter code (DI-Diagnostic Information, Hn-Fault History
Information, and EA-Expanded Annunciator). When the arrow
and two-letter code are displayed, it indicates the second line
is showing a selectable message submenu. The second line
displays selectable or preempt ive messages.
A selectable message supplies information for flame strength,
system status indication, system or self-diagnostics and
troubleshooting.
A preemptive message has parentheses around the message
and supplies a detailed message to support the sequence
status information. A preempt ive message can also be a
lockout message. A preemptive message replaces a
selectable message to support the sequence status
information. It also replaces a selectable message after 60
seconds if it or a lockout message is available.

Run/Test Switch

WARNING
Explosion Hazard.
Can cause serious injury or death.
Do not use the Run/Test switch during the Pilot Flame
Establishing Period for the RM7800/RM7840G,M
when using Direct Spark Function, because it turns on
the main gas valve, causing an accumulation of fuel in
the burner.
The Run/Test Switch is located on the top side of the
RM7800/RM7840, see Fig. 6. The Run/Test Switch allows the
burner sequence to be alte red as follows:
1. In Prepurge Drive To High Fire Position, the Run/Test
Switch, when placed in the TEST position, holds in
PREPURGE with the firing rate motor in the High Fire
position.
2. In the measured PREPURGE sequence, the Run/Test
Switch, when placed in the TEST position, causes the
PREPURGE timing to stop. The firing rate motor is in
the High Fire position.
3. In Prepurge Drive to Low Fire position, the Run/Test
Switch, when placed in the TEST position, holds the
burner sequence in PREPURGE with the firing rate
motor in the Low Fire position.
4. In PFEP, the Run/Test Switch, when placed in the TEST
position, stops the timer during the first eight seconds
when a ten second PFEP is selected or during the first
three seconds when a four second PFEP is selected,
allowing pilot-turn-down test and other burner
adjustments to be made. This activates a fifteen second
flameout timer that permits pilot flame adjustment
without nuisance safety shutdowns. The Run/Test
Switch is ignored during PFEP for the RM7800/
RM7840E,L if Terminals 8 and 9 or 9 and 21 are
jumpered.
5. During Run, the Run/Test Switch, when placed in the
TEST position, drives the firing rate motor to the Low
Fire position.
NOTE: When RM7800/RM7840 is switched to the Test
mode, it stops and holds at the next Run/Test Switch
point in the operating sequence. Make sure that the
Run/Test Switch is in the RUN position before
leaving the installation.
SETTINGS AND ADJUSTMENTS

Selectable Site-Configurable Jumpers

The RM7800/RM7840 has thre e site-configurable jumper
options, see Fig. 6 and Table 7. If necessary, clip the
site-configurable jumpers with side cutters and remove the
resistors from the Relay Module.
Fig. 6. Selectable site-configurable jumpers.
RUN/TEST SWITCH
NOTE: CONFIGURATION JUMPERS SHOWN FOR RM7800G/RM7840G.
SELECTABLE CONFIGURATION JUMPERS
M12301