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INFRARED (C7015)
WHITE
F
BROWN
G
SOLID STATE SELF-CHECKING
ULTRAVIOLET (C7024E,F - E SHOWN)
BLUE
F
1
YELLOW
G
WHITE
22
WHITE
24Vdc (–)
RED
3
BLACK
24Vdc (–)
1
FLAME DETECTOR LEADS ARE COLOR CODED. THE BLUE LEAD
MUST BE CONNECTED TO THE F TERMINAL AND THE YELLOW
MUST BE CONNECTED TO THE G TERMINAL. THE UV SENSING
TUBE IS POLARITY SENSITIVE. REVERSING THE LEADS EVEN
MOMENTARILY CAN DAMAGE OR DESTROY THE UV TUBE.
Fig. 12. Flame detector wiring.
INITIATE
LED
DISPLAY
BURNER
START
OPERATING
CONTROLLER
AND LIMITS
FLAME
SIGNAL
1
2
M7594
00
00
SAFE-
STANDBY
START
POWER
POWER
POWER
LIMITS AND BURNER CONTROL CLOSED
SAFE START CHECK
MAIN FUEL VALVE WILL BE ENERGIZED DURING PFEP IF FLAME IS PROVEN.
RM7890A1031 PFEP IS FIXED 30 SECOND.
Fig. 13. RM7824A sequence.
7800 SERIES RM7824A RELAY MODULE
OPERATION
Sequence of Operation
The RM7824A has the following operation sequence (see
Figs. 13 and 15).
Initiate
The RM7824A enters the INITIATE sequence if the Relay
Module verifies voltage fluctuations of outside 22 to 28 Vdc
during any part of the operating sequence. The INITIATE
sequence lasts for ten seconds unless the voltage tolerance is
not met. When the tolerance is not met, a hold condition will
be initiated and will be displayed on the optional Keyboard
Display Module for at least five seconds. When the tolerance
is met, the INITIATE sequence will restart. If the condition is
not corrected and the hold condition exists for four minutes,
the RM7824A will lock out. Causes for hold conditions in the
INITIATE sequence are:
• Vdc dropout is detected.
• Internal timing functions are not synchronized.
• The noise that can prevent a sufficient reading of the low
voltage inputs.
• Brownouts caused by low input voltage.
Standby
The RM7824A 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 RM7824A to continue into the SAFE-START
CHECK.
Normal Start-Up Safe-Start Check
The RM7824A verifies that a flame does not exist and
proceeds into the ignition trial. If a flame is present, the
RM7824A will recycle to the STANDBY period. If the critical
loads are not in the correct state, a safety shutdown occurs.
4/10
2
PFEP
RUN
4 OR 10 SEC
POWER
POWER
PILOT
PILOT
FLAME
FLAME
MAIN
MAIN
ALARM
ALARM
10
IGNITION
INTERMITTENT PILOT
8
MAIN VALVE
9
3
TO
FLAME PROVING
11
STANDBY
POWER
1
6
S S C
M5135C
65-0155—2
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