Honeywell C7962B Product Data page 3

Visible light flame detector
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WARNING
Explosion Hazard and Electrical Shock Hazard.
Can cause serious injury, death or property
damage.
1. The C7962B Flame Detectors must be used with
Honeywell flame safeguard controls (primaries,
programmers, multiburner systems, and burner
management systems). Using with controls not
manufactured by Honeywell could result in unsafe
conditions.
2. Disconnect power supply before beginning
installation to prevent electrical shock or equipment
damage. More than one disconnect may be
involved.
3. Read the installation instructions before starting the
installation.
4. All wiring must be NEC Class 1 (line voltage).
Basic Requirements for Flame Detector
Installation
It is necessary for the detector to actually see the flame.
Locate the detector as close to the flame as physical
arrangement and temperature restrictions permit.
Sighting requirements for different types of flame supervision
are:
1. Pilot flame only—Sighting must be along the axis of the
pilot flame. The smallest pilot flame that can be sighted
must be capable of igniting the main burner (see Pilot
Turndown Test).
2. Main flame only—Sighting must be at the most stable
part of the flame for all firing rates.
3. Pilot and main flame—Sighting must be at the junction of
both flames.
Mounting a C7962B Flame Detector
Locate the Sight Pipe
The location of the sight pipe is the most critical part of the
installation. A black iron pipe is recommended. Do not use a
stainless steel or galvanized pipe because the internal surface
blackens with use ad deposits from the combustion chamber
settle on it.
Under optimum conditions, the flame detector can detect most
oil combustion flames at a distance of six feet (1.8 meters).
The critical factors in determining the flame-detector distance
separation are the optimized flame signal (current or voltage)
and the flame detector temperature. Other factors may be
influential and are associated with the specific installation. For
minimum flame signals, see Table 1 and for ambient operating
temperatures, refer to Specifications, page 2.
Use 1/2 inch pipe for a C7962B. Since no two situations are
likely to be the same, length and sighting angle of the pipe
must be determined at the time and place of installation.
Generally, it is desirable to have the sight pipe tilting downward
to prevent soot or dirt buildup.
C7962B VISIBLE LIGHT FLAME DETECTOR
If a C7962B is to be used for a blast tube installation, its
location should be determined by the burner manufacturer.
Contact the manufacturer before making any modifications to
the installation.
Prepare Hole in Wall of Combustion Chamber
Cut a hole of the proper diameter for the sight pipe in the wall
of the combustion chamber at the selected location. Flare the
hole to leave room for small adjustments of the sighting angle.
The taper of the hole should be about 1 inch for every 3 inches
(25 mm for every 76 mm) of wall thickness.
Mounting the Sight Pipe (Fig. 2)
Thread one end of the pipe to fit the mounting collar on the
detector. Cut the pipe to the desired length (as short as
practicable) and at an angle so it fits flush with the wall of the
combustion chamber. Tack-weld the pipe to the wall in a trial
position. Do not permanently weld the sight pipe in place until
after completing the Adjustments and Checkout section.
NOTE: If you use a swivel mount (part no. 118367A) and you
are positive about the location and sighting angle, you
can permanently weld the pipe.
FLARED HOLE
REFRACTORY
M3019B
Fig. 2. Mounting sight pipe.
Sight Pipe Ventilation
It may be necessary to ventilate the sight pipe to cool the flame
detector or to clear the sight pipe of UV radiation absorbing
material such as smoke, excessive moisture or, in some
instances, unburned fuel.
For a negative pressure combustion chamber, drilling a few
holes in the section of the sight pipe outside of the combustion
chamber will allow air at atmospheric pressure to flow through
the sight pipe into the chamber. A perforated pipe nipple
between the sight pipe and the detector can also be used.
(See Fig. 3.)
For a positive pressure combustion chamber, connect a supply
of pressurized air from the burner blower through the sight pipe
into the chamber. The supply air pressure must be greater that
the chamber pressure.
Swivel Mount
To facilitate proper sighting of the flame, a swivel mount (part
number 118367A) is available. The swivel mount will require a
3/4 to 1/2 inch reducer and a 1/2 inch close nipple to mount a
C7962B. For mounting details, refer to form 50-0361 for the
118367A Swivel Mount.
3
TEMPORARY
TACK WELD
BLACK IRON
SIGHT PIPE
BOILER
PLATE
65-0277—03

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