Honeywell 7800 Series Installation Instructions Manual page 4

7800 SERIES RM7896D RELAY MODULE
WIRING
1. For proper wiring, refer to Fig. 3. For proper remote
wiring of the Keyboard Display Module, refer to the
Specifications for the Keyboard Display Module
4-line LCD KDM (32-00110), Network Interface Unit
(63-2278), Data ControlBus™ Module (65-0091) or
Extension Cable Assembly (65-0131).
BURNER CONTROL
(127)
POWER
PILOT
PURGE
MAIN
ALARM
RESET
5 (127)
REMOVE ONLY FOR TERMINAL TEST ACCESS.
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Fig. 3. Mounting dimensions of RM7896D Relay
Module and Q7800B Subbase in in. (mm).
WARNING
Electrical Shock Hazard and Equipment
Damage Hazard.
Can cause serious injury, death,
or damage to equipment.
Disconnect power supply from main disconnect
before beginning installation. More than one
disconnection can be involved
2. To prevent electrical shock and equipment damage,
disconnect the power supply from the main
disconnect before beginning installation. More than
one disconnection can be involved.
3. All wiring must comply with all appropriate electrical
codes, ordinances and regulations. Wiring, where
required, must comply with NEC Class 1 (Line
Voltage) wiring. Recommended wire size and type:
use no. 14, 16 or 18 copper conductor ((TTW60C or
THW75C or THHN90C) 600 volt insulation wire for
all line voltage terminals. For high temperature
installations, use wire selected for a temperature
rating above the maximum operating temperature.
All leadwires must be moisture resistant.
4. Recommended grounding practices:
a. Use the earth ground to provide a connection
between the subbase and the control panel or
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.
The RM7896D needs a low impedance ground
connection to the equipment frame which, in
turn, needs a low impedance connection to earth
32-00208-01
5
6-3/32 (155)
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
make 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 mating surface corrosion.
b. RM7896D: Each relay module has an earth
ground terminal that must be grounded to the
metal control panel with wire as short as possi-
ble. Each ground wire must be capable of carry-
ing a fault current equal to the rating of the
protective fuse (20A). A number 14 copper con-
ductor is adequate, but wide straps or brackets
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are preferred rather than leadwires.
5. Recommended wire routing for flame detector
leadwires:
a. Do not run high voltage ignition transformer
wires in the same conduit with the flame detec-
M10449
tion wiring.
b. Do not route scanner wires in a conduit with line
voltage circuits.
c. Enclose scanner wires without armor cable in
metal cable or conduit.
d. Follow directions in flame detector Instructions.
6. Maximum wire lengths:
a. For the RM7896D, the maximum length of
leadwire to the terminal inputs is 300 feet (91.4
meters) (Control and Airflow Interlock).
b. For the flame detector leadwires, the maximum
flame sensor leadwire length is limited by the
flame signal strength.
7. Make sure loads do not exceed the terminal ratings.
Refer to the label on the RM7896D or to the ratings
in the Specifications; see Table 1 in form 32-00156.
8. Check the power supply circuit. The voltage and
frequency tolerance must match those of the
RM7896D. A separate power supply circuit can be
required for the RM7896D with the required
disconnect means and overload protection added.
9. Check all wiring circuits and complete the Static
Checkout (see Table 4 in form 32-00156) before
installing the RM7896D on the subbase.
10. Install all electrical connectors.
11. Restore power to the panel.
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