Operation; Installation - Honeywell C7915A Information

C7915A
MOUNT
1
2 [58]
4
1
1 [32]
4
FOCUSING
LENS
COLLAR,
3/4 - 14 NPSM
50019469-001
INTERNAL THREADS
BUSHING
1
1 [32]
4
50019469-001
BUSHING
COLLAR,
3/4 - 14 NPSM
INTERNAL THREADS
Fig. 1. Mounting dimensions of C7915A Infrared Flame Detector and accessories, in inches. (mm).

OPERATION

OPERATION OF INFRARED
DETECTORS
Infrared detectors can be used with gas, oil, coal, or dual-fuel
flames. Since more than 90% of the total flame radiation is
infrared, these detectors receive ample radiation and can
detect weak flames as well as flames of higher intensity.
The lead sulfide cell used in the detector cannot distinguish
between the infrared radiation emitted by hot refractory and the
infrared radiation from a flame. Therefore, the infrared
detection system includes an amplifier that responds only to
the flickering characteristic of flame radiation and rejects the
steady radiation characteristic of hot refractory.
Unfortunately, smoke or fuel mist within the combustion
chamber can intermittently reflect, bend, or block the hot
refractory radiation, thus making it fluctuate. This fluctuating
action can simulate the flickering radiation from a flame, and
infrared radiation may be present even after the refractory has
visibly stopped glowing. Therefore, be very careful when
applying an infrared detection system to be sure it responds
only to flame.
105172A
SEAL-OFF ADAPTER
105061
HEAT BLOCK
1
5
1 [43]
8 17
[41]
32
9
[13.5]
16
[14]
1
1 [32]
4
3/4 - 14 NPSM
INTERNAL THREADS
3/4 - 14 NPSM
EXTERNAL THREADS
INSTALLING OR REPLACING A C7915A AND ACCESSORIES
105061
HEAT BLOCK
5
1
8
[41]
9
C7915A
16
MOUNT
1
[14]
1
1
16
2 [58]
4
[27]
FOCUSING
3/4 - 14 NPSM
LENS
INTERNAL THREADS
3/4 - 14 NPSM
EXTERNAL THREADS
REPLACING A FIREYE LEAD SULFIDE DETECTOR
11
16
5
1
32
3/4 INCH PIPE NIPPLE
[29 ]
1
1 [32]
4
3/4 - 14 NPSM
INTERNAL THREADS
3/4 - 14 NPSM
EXTERNAL THREADS
390427A
REDUCER
BUSHING
9
[14]
16
1
1 [32]
4
1/2 - 14 NPT
INTERNAL THREADS
3/4 - 14 NPT
EXTERNAL THREADS
CELL CONSTRUCTION
The photosensitive material used in the infrared detector is
lead sulfide. The electrical resistance of lead sulfide decreases
when exposed to infrared radiation. If a voltage is applied
across the lead sulfide photocell, current flows when the cell is
exposed to infrared radiation.

INSTALLATION

WHEN INSTALLING THIS PRODUCT...
1. Read these instructions carefully. Failure to follow them
could damage the product or cause a hazardous condi-
tion.
2. Check the ratings given in the instructions and on the
product to make sure the product is suitable for your
application.
3. Installer must be a trained, experienced flame safeguard
control service technician.
4. After installation is complete, check out product opera-
tion as provided in these instructions.
3
C7915A INFRARED FLAME DETECTOR
105134
ORIFICE
PLATE IN
3/4 INCH
COUPLING
3/4 INCH
SIGHT PIPE
1/2 INCH
SIGHT PIPE
M23448A
65-0292-06