RM7885A 7800 SERIES RELAY MODULES
32-00215—01
4
1.
For proper subbase wiring and sequence chart, refer
to Fig. 2. For other possible wiring hookups, see Fig.
3 through 6.
2.
For proper remote wiring of the KDM, refer to the
Specifications for the 2-line VDF KDM (65-0090),
the 4-line LCD KDM (32-00110), Data ControlBus
Module™ (65-0091) or Extension Cable Assembly
(65-0131).
3.
Disconnect the power supply from the main discon-
nect before beginning installation to prevent electri-
cal shock and equipment damage. More than one
disconnect may be required.
4.
All wiring must comply with all applicable electrical
codes, ordinances and regulations. Wiring, where
required, must comply with NEC, Class 1 (Line Volt-
age) wiring.
5.
For recommended wire size and type, see Table 1.
6.
For recommended grounding practices, see Table 2.
7.
Recommended wire routing of leadwires:
a. Do not run high voltage ignition transformer
wires in the same conduit with the flame
detector, Data ControlBus Module™, or Remote
Reset Module wiring.
b. Do not route flame detector, Data ControlBus
Module™ or Remote Reset Module leadwires in
conduit with line voltage circuits.
c. Enclose flame detector leadwires without armor
cable in metal cable or conduit.
d. Follow directions in flame detector, Data Control-
Bus Module™, or Remote Reset Module Instruc-
tions.
8.
For KDM, because the KDM is powered from a low
voltage, energy limited source, it can be mounted
outside of a control panel if it is protected from
mechanical damage.
NOTE:
A 13 Vdc power supply must be used any time
more than one KDM is used. A maximum of two
KDM, Data ControlBusª Modules or S7810B
Multi-Drop Switch Modules are allowed in any
combination.
9.
Maximum wire lengths:
a. RM7885A leadwires: The maximum leadwire
length is 300 feet (91 meters) to terminal inputs
(Control, Preignition Interlock, Running/Lock-
out Interlock, High Fire Switch and Low Fire
Switch).
b. Flame Detector leadwires: The maximum flame
sensor leadwire length is limited by the flame
signal strength.
c. Remote Reset leadwires: The maximum length of
wire is 1000 feet (305 meters) to a Remote Reset
pushbutton.
d. Data ControlBus Moduleª: The maximum Data
ControlBus Module™ cable length depends on
the number of system modules connected, the
noise conditions and the cable used. The
maximum length of all Data ControlBus Moduleª
interconnecting wire is 4000 feet (1219 meters).
10.
Be sure loads do not exceed the terminal ratings.
Refer to the label on the RM7885A or to the terminal
ratings in Table 4.