7800 SERIES EC7885A/RM7885A RELAY MODULE
65-0203
12
Fig. 8. High-low or modulating burner diagram.
Fig. 8 shows the use of a high-low or modulating motor with
the 7885A. Note that the starting circuit cannot be energized
until the end switch of the high-low or modulating motor is in
the low fire position. Also to prevent the high-low or
modulating motor from running in the high fire position before
the manually opened safety-shutoff valve is opened, a fuel
pressure switch (connected downstream from the shut-off
valve) is connected in series with the R482B Relay. This
assures that the burner will lightoff in the low fire position
before the controller can take command of the burner.
M11179
G
L2
3
5
6
7
8
9
10
F
(L1)
13
14
15
16
17
18
19
20
21
22
12
MASTER
SWITCH
IGNITION
LOW FIRE MOTOR
END SWITCH
INTERMITTENT
PILOT
100V, 50 OR 60 HZ. (RM7885); 200V, 50 OR 60 HZ (EC7885) POWER SUPPLY.
PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
DO NOT CONNECT ANY WIRES TO UNUSED TERMINALS.
100V ALARM (RM7885); 200V ALARM (EC7885).
ALARM
L1
(HOT)
L2
Q7800
4
1
2
3
3
2
1
LIMITS
STOP
S445A
START-STOP
STATION
START
B
A
D
C
INTERNAL
JUMPER
DPST ALARM
SILENCING
SWITCH
FUEL
PRESSURE
SWITCH
MANUAL
VALVE
1
2
6
7
8
R
W
B
R
W
B
T
T
CONTROLLER
HI-LO OR
MODULATING
MOTOR
R482B
