Honeywell 7800 Series Manual page 14

RM7838B
INSTALLATION
IMPORTANT:
1. For on-off gas-fired systems, some authorities who
have jurisdiction prohibit the wiring of any limit or
operating contacts in series between the flame safe-
guard control and the main fuel valve(s).
2. Do not connect more than two C7012E,F or C7076A,D
Ultraviolet Flame Detectors (with self-checking shutter)
in parallel to the same terminal.
3. This equipment generates, uses and can radiate radio
frequency energy and, if not installed and used in
accordance with the instructions, may cause interfer-
ence to radio communications. It has been tested and
found to comply with the limits for a Class B comput-
ing device of Part 15 of FCC rules, which are designed
to provide reasonable protection against such interfer-
ence when operated in a commercial environment. Op-
eration of this equipment in a residential area may cause
interference; in which case, the users at their own expense
may be required to take whatever measures are required
to correct this interference.
4. This digital apparatus does not exceed the Class B
limits for radio noise for digital apparatus set out on
the Radio Interference Regulations of the Canadian
Department of Communications.
5. The RM7838B cannot be connected in parallel with-
out isolation circuits between the input and output
circuits of each device.
HUMIDITY
Install the RM7838B where the relative humidity never
reaches the saturation point. The RM7838B is designed to
operate in a maximum 85% RH continuous, noncondensing,
moisture environment. Condensing moisture may cause a
safety shutdown.
VIBRATION
Do not install the RM7838B where it could be subjected to
vibration in excess of 0.5G continuous maximum vibration.
WEATHER
The RM7838B is not designed to be weather tight. If
installed outdoors, the RM7838B must be protected by an
approved weather-tight enclosure.
MOUNTING THE WIRING SUBBASE
NOTE: For installation dimensions, see Fig. 1 and 2.
1. Mount the subbase in any position except horizon-
tally with the bifurcated contacts pointing down. The stan-
dard vertical position is recommended. Any other position
decreases the maximum ambient temperature rating.
2. Select the location on a wall, burner or electrical panel.
The Q7800 Subbase can be mounted directly in the control
cabinet. Be sure to allow adequate clearance for servicing,
installation, access or removal of the RM7838B, S7830
Expanded Annunciator, S7800 Keyboard Display Module,
flame amplifier, flame amplifier signal voltage probes, Run/
Test Switch, electrical signal voltage probes and electrical
field connections.
65-0120—1
3. For surface mounting, use the template (see Fig. 32) to
mark the four screw locations. Drill the pilot holes.
4. Securely mount the subbase using four no. 6 screws.
WIRING
1. For proper subbase wiring, refer to Figs. 8, 9 or 10.
For proper wiring of the Keyboard Display Module, refer to
Figs. 9 and 10, or to the Specifications of the Keyboard Dis-
play Module (65-0090), Communication Interface Base Unit
(63-2278), DATA CONTROLBUS MODULE™ (65-0091)
or Extension Cable Assembly (65-0131).
2. Disconnect the power supply from the main discon-
nect before beginning installation to prevent electrical shock
and equipment damage. More than one disconnect may be
involved.
3. All wiring must comply with all applicable electrical
codes, ordinances and regulations. Wiring, where required,
must comply with NEC, Class 1 (Line Voltage) wiring.
4. Recommended wire size and type:
a. All Line Voltage terminals use no. 14, 16, or 18
copper conductor (TTW60C or THW75C or
THHN90C) 600 volt insulation wire. For high
temperature installations, use wire selected for a
temperature rating above the maximum operating
temperature. All leadwires should be moisture
resistant.
b. Keyboard Display Module—For communications
purposes, use an unshielded 3-wire twisted cable if
the leadwire run and noise conditions permit; how-
ever, some installations may need up to five wires,
three for communications and two for remote reset
(in either a single cable or separate cables for com-
munications or remote reset) or use Belden 8771
shielded cable or equivalent. The Keyboard Display
Module, DATA CONTROLBUS MODULE™ (for
remote mounting or communications) or Communi-
cation Interface ControlBus Module 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 may require a 120 ohm
(1/4 watt minimum) resistor termination across
terminals 1 and 2 of the electrical connectors, see
Figs. 11 and 12.
c. DATA CONTROLBUS MODULE™—For com-
munications purposes, use an unshielded 3-wire
twisted cable if the leadwire run and noise condi-
tions permit; however, some installations may need
up to five wires, three for communications and two
for remote reset (in either a single cable or separate
cables) or use a Belden 8771 shielded cable or
equivalent. The Keyboard Display Module, DATA
CONTROLBUS MODULE™ (for remote mount-
ing or communications) or Communication Inter-
face ControlBus Module 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 mod-
ules on the closest and farthest end of the daisy
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