CB780/CB784 RELAY MODULES
9 32-00207—01
3. Wiring, where required, must comply with NEC Class
1 (Line Voltage) wiring.
4. Loads connected to the CB780/CB784 must not
exceed those listed on the CB780/CB784 label or
the Specifications, see Table 1.
5. Limits and interlocks must be rated to simultane-
ously carry and break current to the ignition trans-
former, pilot valve, and main fuel valve(s).
6. All external timers must be listed or component rec-
ognized by authorities who have jurisdiction for the
specific purpose for which they are used.
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
safeguard control and the main fuel valve(s).
2. Two Flame Detectors can be connected in parallel
with the exception of Infrared Flame Detector
(817-1742).
3. This equipment generates, uses and can radiate
radio frequency energy and, if not installed and
used in accordance with the instructions, may
cause interference to radio communications. It
has been tested and found to comply with the lim-
its for a Class A computing device of Part 15 of
FCC rules which are designed to provide reason-
able protection against such interference when
operated in a commercial environment. Operation
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 mea-
sures are required to correct this interference.
4. This digital apparatus does not exceed the Class A
limits for radio noise for digital apparatus set out
in the Radio Interference Regulations of the Cana-
dian Department of Communications.
Humidity
Install the CB780/CB784 where the relative humidity
never reaches the saturation point. The CB780/CB784 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 CB780/CB784 where it could be
subjected to vibration in excess of 0.5G continuous
maximum vibration.
Weather
The CB780/CB784 is not designed to be weather tight. If
installed outdoors, the CB780/CB784 must be protected
by an approved weather-tight enclosure.
Mounting Wiring Subbase
NOTE: For installation dimensions, see Fig. 1.
1. Mount the subbase in any position except horizon-
tally with the bifurcated contacts pointing down. The
standard vertical position is recommended. Any
other position decreases the maximum ambient
temperature rating.
2. The 833-2725 Wiring Subbase can be mounted
directly in the control cabinet. Be sure to allow ade-
quate clearance for servicing, installation, access or
removal of the CB780/CB784, Expanded Annuncia-
tor, Keyboard Display Module, flame amplifier, flame
amplifier signal voltage probes, Run/Test Switch,
electrical signal voltage probes and electrical field
connections.
3. For surface mounting, use the back of the subbase
as a template to mark the four screw locations. Drill
the pilot holes.
4. Securely mount the subbase using four no. 6 screws.
WIRING
1. Proper Wiring:
a. For proper subbase wiring, refer to Fig. 7.
b. For proper remote wiring of the Keyboard Display
Module, refer to Fig. 8, 9 or 10 or to the Specifica-
tions for the Keyboard Display Module, Modbus™
Module or DATA CONTROLBUS MODULE™.
2. Disconnect the power supply from the main discon-
nect before beginning installation to prevent electri-
cal 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 Volt-
age) wiring.
4. Recommended wire size and type:
a. All Line Voltage terminals use no. 14 or 16 cop-
per conductor (90°C or higher) 600 volt insula-
tion wire (wire size must be coordinated with fuse
protection). For high temperature installations,
use wire selected for a temperature rating above
the maximum operating temperature. All lead-
wires should be moisture resistant.
b. Keyboard Display Module—For communications
purposes, use an unshielded 22 AWG 2-wire
twisted cable and one wire for ground if the lead-
wire run and noise conditions 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
for communications or remote reset) or use
Belden 8771 shielded cable or equivalent. The
Keyboard Display Module, DATA CONTROLBUS
MODULE™ (for remote mounting or communica-
tions) or Modbus 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 require a
120 ohm (1/4 watt minimum) resistor termina-
tion across terminals 1 and 2 of the electrical
connectors, for connections over 100 feet, see
Fig. 8, 9 and 10.
c. DATA CONTROLBUS MODULE™—For communi-
cations purposes, use an unshielded 22 AWG 2-
wire twisted cable if the leadwire run and noise
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