Honeywell 7800 Series Manual page 14

RM7800E,G,L,M
WIRING
preferred rather than leadwires. Be careful to en-
sure that mechanically tightened joints along
the ground path, such as pipe or conduit threads
or surfaces held together with fasteners, are free of
nonconductive coatings and are protected against
corrosion on mating surfaces.
b. Keyboard Display Module, DATA CONTROLBUS
MODULE™ or Communication Interface
ControlBus Module—The shield, if used, should
be connected to the signal ground terminal 3(c)
provided as part of the 7800 SERIES device
ControlBus connection. Connect the shield at both
ends to earth ground.
c. RM7800—Each RM7800 will have an earth ground
terminal that must be grounded to the metal control
panel with wire as short as practical. Each ground
wire must be capable of carrying a fault current
equal to the rating of the protective fuse (20A).
A number 14 copper conductor is adequate, but
wide straps or brackets are preferred rather than
leadwires.
6. Recommended wire routing:
a. Flame detector leadwires:
1. Do not run high voltage ignition transformer
wires in the same conduit with the flame detec-
tion wiring.
2. Do not route scanner wires in conduit with line
voltage circuits.
3. Enclose scanner wires without armor cable in
metal cable or conduit.
4. Follow directions in flame detector Instructions.
b. DATA CONTROLBUS MODULE™:
1. Do not run high voltage ignition transformer
wires in the same conduit or close proximity
with the DATA CONTROLBUS MODULE™
wiring.
2. Do not route DATA CONTROLBUS MOD-
ULE™ wires in conduit with line voltage
circuits.
c. Keyboard Display Module (VFD): Because the
VFD is powered from a low voltage, energy lim-
ited source, it can be mounted outside of a control
panel if it is protected from mechanical damage.
d. Remote Reset:
1. Do not run high voltage ignition transformer
wires in the same conduit with the Remote
Reset wiring.
2. Do not route Remote Reset wires in conduit
with line voltage circuits.
NOTE: A 13 Vdc power supply must be used any time more
than one Keyboard Display Module is used.
7. Maximum wire lengths:
a. RM7800 leadwires—The maximum length of
leadwire is 300 feet to terminal inputs (Control,
Preignition Interlock, Running/Lockout 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 to a Remote Reset pushbutton.
d. DATA CONTROLBUS MODULE™—The maxi-
mum 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 interconnecting
wire is 1000 feet.
8. Make sure loads do not exceed the terminal ratings.
Refer to the label on the RM7800 or to the ratings in
Specifications, see Table 1.
9. Check the power supply circuit. The voltage and
frequency tolerance must match those of the RM7800. A
separate power supply circuit may be required for the
RM7800. Add the required disconnect means and over-
load protection.
10. Check all wiring circuits and complete the Static
Checkout, see Table 7, before installing the RM7800 on
the subbase.
11. Install all electrical connectors.
12. Restore power to the panel.
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