C7961E,F DYNAMIC SELF-CHECK ULTRAVIOLET FLAME DETECTOR
65-0267-09 6
Mount Sight Pipe
Thread one end of the pipe to fit the mounting flange, union, or 
required coupling. Cut the pipe to the desired length (as short 
as practical) 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 weld the sight pipe permanently in place until 
after completing the Adjustments and Checkout.
NOTE:If you use 118367A Swivel Mount and you are positive 
about the location and sighting angle, you can permanently 
weld the pipe.
Install Fittings
In some cases, the sight pipe does not directly fit the C7961 
mounting flange or union. Also, it may be desirable or 
necessary to ventilate the sight pipe. You may also want to use 
a swivel mount or an antivibration mount. Each of these cases 
can require additional fittings.
Reducer
For sight pipes of larger diameter than the mounting flange 
connector or union, install a reducer as illustrated in Fig. 5. The 
reducer requires a close nipple with 3/4 in. NPT external 
threads:
Sight Pipe Ventilation
It may be necessary to ventilate the sight pipe to cool the 
detector or to clear a viewing path through UV radiation 
attenuating material.
For a negative pressure combustion chamber, drilling a few 
holes in the section of the sight pipe outside of the combustion 
chamber allows air at atmospheric pressure to flow through the 
sight pipe and into the chamber. A perforated pipe nipple 
between the sight pipe and the detector can also be used.
For a positive pressure combustion chamber, connect a supply 
of pressurized air from the burner blower to flow through the 
sight pipe and into the chamber. The air pressure must be 
greater than the chamber pressure.
Swivel Mount
To facilitate proper flame sighting, use 118367A Swivel Mount 
(ordered separately). The swivel mount requires a reducer of 
the proper size to mount it onto the sight pipe. It also requires a 
one-inch close nipple for mounting to a C7961 with a 
one-inch connector. (For 118367A Swivel Mount mounting 
details, refer to 60-0361.)
Antivibration Mount 
The detector withstands normal burner vibration. If the 
vibration is excessive, 123539 Antivibration Mount is available. 
(For mounting details, see form 60-0361.) If you use this 
mount, install it before positioning and sighting the detector.
Mount the Detector (Fig. 5-8)
Mount the detector onto the sight pipe, reducer, or other fitting 
(see Fig. 5-8).
The C7961 Self-Checking Flame Detectors incorporate an 
oscillating shutter mechanism and, therefore, require special 
consideration for mounting positions other than vertically 
sighting downward or upward, as illustrated in Fig. 6. The 
C7961 has notch and arrow indicators (see Fig. 7) on the 
faceplate to facilitate mounting in positions other than those 
shown in Fig. 6. The notch and arrow must be vertically aligned 
with the notch in the up position and the arrow pointing 
downward (see Fig. 7). The C7961 must be mounted with the 
conduit opening located approximately 45 degrees below the 
horizontal (see Fig. 7).
Fig. 6. Vertical mounting of C7961E.
Fig. 7. C7961 mounting positions.
C7961 SIGHTING
VERTICALLY DOWNWARD
BURNER
COMBUSTION
CHAMBER WALL
C7961 SIGHTING
VERTICALLY UPWARD
M34213
1
M34214
VERTICAL
PLANE
NOTCH AND ARROW
MUST ALWAYS BE
ALIGNED IN A 
VERTICAL PLANE
NOTCH IN FACEPLATE
MUST BE UP
HORIZONTAL
PLANE
ARROW ON FACEPLATE
MUST BE POINTING
DOWN
C7961 
MUST NOT
BE ROTATED
AROUND
ITS AXIS
NOTE DOWNWARD
POSITIONING OF
CONDUIT OPENING.
HORIZONTAL
PLANE
1
1
1
90
90
45