Assembly - Honeywell 7800 Series Manual

c. RM7888A—Each RM7888A 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 to leadwires.
6. Recommended wire routing:
a. Flame detector leadwires:
1. Do not run high voltage ignition transformer wires
in the same conduit with flame detection wiring.
2. Do not route scanner wires in a conduit with line
voltage circuits.
3. Enclose scanner wires without armor cable in metal
cable or conduit.
4. Follow directions given in flame detector instructions.
b. DATA CONTROLBUS MODULE™:
1. Do not run high voltage ignition transformer wires
in the same conduit or in close proximity to the
DATA CONTROLBUS MODULE™ wiring.
2. Do not route DATA CONTROLBUS MODULE™
wires in conduit with line voltage circuits.
c. Keyboard Display Module:
1. Because the VFD is powered from a low voltage,
energy limited source, mount it outside a control
panel, without using special wiring procedures, if
it is protected from mechanical damage.
MOUNTING THE RM7888A
NOTE: For installation dimensions, see Figs. 1 or 2.
RELAY MODULE MOUNTING(FIGS. 11 AND 12)
1. Mount RM7888A vertically, see Figs. 11 or 12, or
mount horizontally with the knife blade terminals pointing
downward. When mounted on the Q7800A, the RM7888A
must be in an electrical enclosure.
2. Select the location in the electrical enclosure. Be sure
to allow adequate clearance for servicing, installation and
removal of the RM7888A, Keyboard Display Module, flame
amplifier, flame amplifier signal voltage probes, electrical
signal voltage probes and electrical connections.
a. Allow an additional two inches below the RM7888A
for the flame amplifier mounting.
b. Allow an optional three-inch minimum to both sides
of the RM7888A for electrical signal voltage probes.
3. Make sure no subbase wiring is projecting beyond
the terminal blocks. Tuck in wiring against the back of the
subbase so it does not interfere with the knife blade termi-
nals or bifurcated contacts.
IMPORTANT: The RM7888A must be installed with a
plug-in motion rather than a hinge action.
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 the same con-
duit with line voltage circuits.
7. Maximum wire lengths:
a. For the flame detector leadwires, the maximum flame
sensor leadwire length is limited by the flame signal
strength.
b. For the Remote Reset leadwires, the maximum length
of wire is 1000 feet to a Remote Reset pushbutton.
c. For the DATA CONTROLBUS MODULE™, the max-
imum 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 [305 meters].
8. Make sure loads do not exceed the terminal ratings.
Refer to the label on the RM7888A or to the ratings in the
specifications; see Table 1.
9. Check the power supply circuit. The voltage and
frequency tolerance must match those of the RM7888A. A
separate power supply circuit may be required for the
RM7888A with the required disconnect means and over-
load protection added.
10. Check all wiring circuits and complete the Static
Checkout before installing the RM7888A on the subbase:
see Table 10.
11. Install all electrical connectors.
12. Restore power to the panel.
Fig. 11—Electrical panel installation.
15
RM7888A
WIRING • ASSEMBLY

Assembly

65-0175