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C7076A,D ADJUSTABLE SENSITIVITY ULTRAVIOLET FLAME DETECTORS
Installing the C7076A Detector
Mounting the Aspirator
The aspirator on the faceplate of the C7076A Detector screws
directly onto the 1-inch NPT threaded pipe. Remove the
aspirator from the C7076A Detector by removing the hinge pin.
Use an adjustable wrench to tighten the aspirator onto the
pipe. For alternate mounting methods and further information
refer to Fig. 5.
Mounting the Detector
Mount the detector on the faceplate by placing the detector on
its hinge and re-inserting the hinge pin. Install 1/2 inch flexible
conduit to the detector as follows:
Loosen the four captive screws in the front coverplate (with the
viewing lens) and remove the plate.
Install a flexible conduit fitting in the opening in the bottom of
the detector (Fig. 7). To meet NEMA 4 standards, use
watertight conduit and a watertight fitting (such as an Appleton
ST50 Liquid-Tight® Connector with an STG-50 Neoprene
O-ring and Steel Gasket Assembly). See Table 2 for other
applicable connectors.
Table 2. Applicable Watertight Connectors.
Manufacturer
Coupling No.
T&B
5232
Efcor
11-50
Raco
3402
Steel City
LT-101
Crouse Hines
LT-50
Connecting Air Supply (Optional)
Use a flexible air supply line which will allow repositioning of
the sight pipe until the permanent detector position has been
verified.
The aspirator air inlet can be plugged, left open, or connected
to a clean (oil/moisture-free) air supply. Use a 3/8 in. NPT
connector if aspirator air is used (see Fig. 5). The aspirator
allows air to flow through the sight pipe into the combustion
chamber to cool, clean and seal off the sight pipe. The airflow
eliminates the need for frequent lens cleaning. See Fig. 8 for
purge air requirements.
Seal off of the sight pipe prevents hot gases from escaping
from a positive pressure combustion chamber when the
detector is swung open on its hinge for maintenance. Refer to
Fig. 9 for the minimum inlet pressure or air flow required to seal
off a sight pipe against a positive combustion chamber
pressure.
95-8269—04
Fig. 10 shows a method of supplying a constant airflow to
purge the sight pipe, while also providing enough pressure to
seal off the sight pipe when needed.
Mounting the Faceplate
The faceplate of the C7076D Detector screws directly onto the
1-inch NPT threaded pipe (see Fig. 5). Screw the faceplate
onto the pipe; hand-tighten in place, making certain that the
four mounting holes in the faceplate are properly aligned to
allow the detector to be in the desired position when secured to
the faceplate.
Mounting the Detector
Mount the detector on the faceplate and fasten in place using
the four mounting screws supplied for this purpose. Do not
tighten the screws at this time, because the detector must still
be wired.
Obtain a piece of conduit that is not longer than 18 inches in
length and has 1/2-inch NPT threads at both ends. Screw this
piece of conduit into the threaded opening in the bottom of the
detector housing (see fig. 11). Install an approved seal box on
the other end of the piece of conduit and then complete the
conduit installation as required.
WIRING
O-Ring No.
5262
LTG-1
2452
LR-531
SG-1
NOTE: The detector has color-coded and labeled,
8
WARNING
Electrical Shock Hazard.
Can cause serious injury, death or property
damage.
Disconnect all power before beginning wiring. More
than one disconnect may be involved.
1. All wiring must comply with applicable local electrical
codes, ordinances and regulations. Use NEC Class 1
wiring.
plastic-insulated no. 18 leadwires, 8 ft (2.4 m) long,
rated for 221°F (105°C).
2. Keep the flame signal leadwires as short as possible
from the flame detector to the terminal strip or wiring
subbase. Capacitance increases with wire length,
reducing the signal strength. the maximum permissible
leadwire length depends on the type of leadwire and the
conduit type and diameter. The ultimate limiting factor in
flame signal leadwire length is the signal current or
voltage at the flame safeguard device. See Table 1.
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