Honeywell 7800 Series Manual page 10

7800 SERIES RM7830A, RM7850A RELAY MODULE
Mounting Wiring Subbase
NOTE: For installation dimensions, see Fig. 1.
Mount the subbase (Q7800) in any position except
horizontally with the bifurcated contacts pointing down.
The standard vertical position is recommended. Any
other position decreases the maximum ambient
temperature rating.
Select a location within an electrical panel. The subbase
must be mounted directly in the control cabinet. Be sure
to allow adequate clearance for servicing, installation,
access or removal of the Relay Module, Keyboard
Display Module, flame amplifier, flame amplifier signal
voltage probes, Run/Test Switch, electrical signal voltage
probes and electrical field connections.
For surface mounting, use the back of the subbase as a
template to mark the four screw locations. Drill the pilot
holes.
Securely mount the subbase using four M3.5 x 0.6
screws.
Wiring
a. For proper subbase wiring, refer to Fig. 4.
b. For proper remote wiring of the Keyboard Display
Module, refer to Fig. 5 or 6 or to the Specifications
for the Keyboard Display Module (65-0166), DATA
CONTROLBUS MODULE™ (65-0091) or
Extension Cable Assembly (65-0131).
Disconnect the power supply from the main disconnect
before beginning installation to prevent electrical shock
and equipment damage. More than one disconnect
may be involved.
All wiring must comply with all applicable electrical codes,
ordinances and regulations. The Keyboard Display
Module, DATA CONTROLBUS MODULE™ (for remote
mounting) or Remote Reset Module (for remote reset)
must be wired in a daisy chain configuration, (1(a)-1(a),
2(b)-2(b), 3(c)-3(c)). The order of interconnection of all
the devices listed above is not important. Be aware that
modules on the closest and farthest end of the daisy
chain configuration string require a 120 ohm (1/4 watt
minimum) resistor termination across terminals 1 and 2
of the electrical connectors, for connections over 30
meters, see Fig. 5 and 6.
Recommended grounding practices:
a. The earth ground provides for a connection
between the subbase and the control panel of the
equipment. The earth ground wire must be
capable of conducting the current to blow the 20A
fuse (or breaker) in event of an internal short
circuit. It is recommended that the Relay Module
have a low impedance ground connection to the
equipment frame which, in turn, needs a low
impedance connection to earth ground. For a
ground path to be low impedance at RF
frequencies, the connection must be made with
minimum length conductors that have a
maximum surface area. Wide straps or brackets
are preferred rather than leadwires. Be careful to
ensure 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.
65-0222
b. Keyboard Display Module, DATA CONTROLBUS
MODULE™ or Remote Reset Module—The
shield, if used, should be connected to the signal
ground terminal 3(c) provided as part of the 7800
SERIES device connection. Connect the shield at
both ends to earth ground.
c. Relay Module—Each Relay Module 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). Wide straps or brackets are
preferred rather than leadwires.
Recommended wire routing:
a. Flame detector leadwires:
1. Do not run high voltage ignition transformer
wires in the same conduit with the flame
detection wiring.
2. Do not route flame detector wires in conduit
with line voltage circuits.
3. Enclose flame detector 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
MODULE™ wires in conduit with line voltage
circuits.
c. 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.
Maximum wire lengths:
a. Flame Detector leadwires—The maximum flame
sensor leadwire length is limited by the flame
signal strength.
b. Remote Reset leadwires—The maximum length
of wire is 300 meters to a Remote Reset
pushbutton.
c. DATA CONTROLBUS MODULE™—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
interconnecting wire is 300 meters.
Make sure loads do not exceed the terminal ratings.
Refer to the label on the Relay Module or to the ratings
in Specifications, see Table 1.
Check the power supply circuit. The voltage and
frequency tolerance must match those of the Relay
Module. A separate power supply circuit may be
required for the Relay Module. Add the required
disconnect means and overload protection.
Check all wiring circuits before installing the Relay
Module on the subbase.
Install all electrical connectors.
Restore power to the panel.
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