65-0292-06
C7915A Infrared Flame Detector
PRODUCT DATA
• Mounts easily on a standard 3/4 inch sight pipe.
• The infrared sensor plugs into an electrical socket in the
C7915A assembly and is field replaceable.
• The lead sulfide photocell’s sensitivity to infrared radiation
is compatible with a wide range of flame supervisory
applications.
• Flexible metal cable protects and electrically shields the
detector coaxial cables.
• Accessories available include a heat block, seal-off
adapter, reducer bushing, and orifice plate.
• Immune to x-ray testing.
SPECIFICATIONS
STANDARD MODELS
MODELS: See Table 6 for flame safeguard controls and asso-
ciated amplifiers.
DETECTOR RESPONSE: Responds to infrared radiation with
APPLICATION
The C7915A Flame Detector includes a lead sulfide photocell
that is sensitive to the infrared radiation emitted by the
combustion of fuels such as natural gas, oil, and coal.
• Particularly suitable for combination or dual-fuel
applications.
• When installed properly, can supervise the pilot flame and/
or the main burner flame.
wavelengths between 0.75 and 1.0 micron.
LEAD SULFIDE PHOTOCELL: Photo conductor resistance
decreases as incident radiant energy increases.
AMBIENT TEMPERATURE RATING: -40°F to 125°F (-40°C to
52°C) maximum at the lead sulfide photocell.
MOUNTING:
C7915A Mount—knurled collar with 3/4-14 NPSM internal
threads for mounting on a standard 3/4 in. pipe (see Fig. 1).
32007255-001 Lead Sulfide Photocell—two leads for inserting
into socket in C7915A (see Fig. 8).
Contents
Application ........................................................................ 1
Specifications ................................................................... 1
Ordering Information ........................................................ 2
Operation .......................................................................... 3
Installation ........................................................................ 3
Wiring ............................................................................... 8
Adjustments and Checkout ............................................... 10
Troubleshooting ................................................................ 11
C7915A INFRARED FLAME DETECTOR
Table 1. Models Available
Coaxial Cable
Components Included
Length
Model
(in.) (m)
Lead Sulfide Cell
50019469-001
Bushing With
Magnifying Lens
105134
Orifice
a
Plate
105061
Heat Block
390427A
Reducer
b
Bushing
C7915A1010 30 0.76 32007255-001 X X
C7915A1036 96 2.44 32007255-001 X X
C7915A1028 48 1.22 32007255-001 X X X X
a
With 0.125 in. (3.175 mm) diameter hexagonal orifice to reduce the detector field of view.
b
To insulate the detector from sight pipe temperatures higher than -40°F–125°F (-40°C–52°C) and up to 250°F (121°C).
c
To mount the detector on a 1/2 in. sight pipe, specifically to replace Fireye™ lead sulfide infrared flame detectors.
c
WIRING CONNECTIONS
Nominal 48 in. (1.22 m) coaxial cables—rated for 194°F
(90°C); terminated—one blue and one white.
Coaxial cables enclosed in flexible metal cable—3/8 in. (9.6
mm) maximum outer diameter.
DIMENSIONS: See Fig. 1.
SIL 3 CAPABLE:
The C7915 when used with a R7852B Ampli-check amplifier
in Relay Module EC7810A, 20A, 30A, 40L, 50A;
RM7800[E,G,L,M], 30A, 38[A,B,C], 40[E,G,L,M] 50A,
90[A,B,C,D], 97[A,C], 98A is SIL 3 Capable in a properly
designed Safety Instrumented System. See form number
65-0312 for Certificate Agreement.
APPROVALS:
Underwriters Laboratories Inc. listed: File No. MP268.
Canadian Standards Association certified: Master file LR-
95329-1.
Factory Mutual approved.
Swiss Re (formerly Industrial Risk Insurers): acceptable.
IMPORTANT:
Caution, stickers, form 96-610, are included with the
C7915A. Underwriters Laboratories Inc. requires that
this sticker be placed on any junction box in which
C7915A coaxial cables are connected. The sticker
prohibits routing any other wiring through the junction
box.
REPLACEMENT PARTS:
32007255-001 Lead Sulfide Photocell
50019469-001 Bushing with Focusing Lens
105061 Heat Block to insulate the detector from sight pipe
temperatures higher than 125°F (52°C) and up to 250°F
(121°C).
390427A Reducer Bushing, to mount the detector on a 1/2 in.
sight pipe; specifically to replace Fireye™ lead sulfide infrared flame detectors.
ACCESSORIES:
105172A Seal-Off Adapter; with glass window to prevent hot
gases from reaching the lead sulfide photocell.
118367A Swivel Mount; provides adjustable positioning of the
C7915A.
Hookup Cable—R1298020; 2-wire, heat- and moisture-resis-
tant, No. 20 AWG, Teflon (TFE) insulated; rated up to
400°F (204°C) for continuous duty; tested for operation up
to 600 volts and breakdown up to 7500 volts.
ORDERING INFORMATION
When purchasing replacement and modernization products from your TRADELINE® wholesaler or distributor, refer to the
TRADELINE® Catalog or price sheets for complete ordering number. If you have additional questions, need further information,
or would like to comment on our products or services, please write or phone:
1. Your local Honeywell Environmental and Combustion Controls Sales Office (check white pages of your phone directory).
2. Honeywell Customer Care
1885 Douglas Drive North
Minneapolis, Minnesota 55422-4386
3. http://customer.honeywell.com or http://customer.honeywell.ca
International Sales and Service Offices in all principal cities of the world. Manufacturing in Belgium, Canada, China, Czech
Republic, Germany, Hungary, Italy, Mexico, Netherlands, United Kingdom, and United States.
65-0292-06 2
C7915A INFRARED FLAME DETECTOR
C7915A
MOUNT
105061
HEAT BLOCK
105172A
SEAL-OFF ADAPTER
105134
ORIFICE
PLATE IN
3/4 INCH
COUPLING
3/4 INCH
SIGHT PIPE
3/4 - 14 NPSM
INTERNAL THREADS
3/4 INCH PIPE NIPPLE
FOCUSING
LENS
COLLAR,
3/4 - 14 NPSM
INTERNAL THREADS
50019469-001
BUSHING
INSTALLING OR REPLACING A C7915A AND ACCESSORIES
1 [32]
1
4
1 [32]
1
4
1
4
2 [58]
1
[43]
11
16
1
[41]
5
8
9
16
[14]
17
32
[13.5]
9
16
[14]
3/4 - 14 NPSM
EXTERNAL THREADS
1 [32]
1
4
3/4 - 14 NPSM
INTERNAL THREADS
3/4 - 14 NPSM
EXTERNAL THREADS
C7915A
MOUNT
105061
HEAT BLOCK
3/4 - 14 NPSM
INTERNAL THREADS
FOCUSING
LENS
COLLAR,
3/4 - 14 NPSM
INTERNAL THREADS
1 [32]
1
4
1 [32]
1
4
1
4
2 [58]
1
[41]
5
8
9
16
[14]
3/4 - 14 NPSM
EXTERNAL THREADS
1/2 INCH
SIGHT PIPE
390427A
REDUCER
BUSHING
3/4 - 14 NPT
EXTERNAL THREADS
1/2 - 14 NPT
INTERNAL THREADS
REPLACING A FIREYE LEAD SULFIDE DETECTOR
M23448A
1
[27]
1
16
1
[29 ]
5
32
50019469-001
BUSHING
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.
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 condition.
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 operation as provided in these instructions.
3 65-0292-06
C7915A INFRARED FLAME DETECTOR
CAUTION
Electrical Shock Hazard.
Disconnect power supply before beginning installation
to prevent electrical shock and equipment damage;
there may be more than one disconnect.
All wiring must be NEC Class 1 (line voltage).
Use the C7915A only with Honeywell lead sulfide
photocells (part no. 32007255-001) and flame signal
amplifiers specified (see Table 6).
NOTICE
Per industry standards, a conduit seal or a cable type that is
sealed is required to be installed in a device that can result in
flammable gas or flammable liquid flow through a conduit or
cable to an electrical ignition source in the event of a seal
leakage or diaphragm failure.
Proper flame detector installation is the basis of a reliable
flame safeguard installation. Refer to the burner manufacturer
instructions and instructions below. Carefully follow instructions
for the best possible flame detector application.
BASIC REQUIREMENTS
Because all flames produce infrared radiation, a C7915A
Infrared (lead sulfide) Flame Detector can be used to prove the
presence of a flame in a combustion chamber. The detector is
mounted outside the combustion chamber. Screw the
mounting collar to one end of a sight pipe inserted through the
wall of the combustion chamber. The lead sulfide photocell in
the detector sights the flame through the sight pipe.
SIGHTING
The infrared detector must continually sight a stable portion of
the flame being detected. The detector is commonly applied to
detect both the gas pilot and main gas flame, or the gas pilot
and main oil flame.
In either case, the detector must be
carefully aimed at the intersection of the pilot and main flame
A Swivel Mount (Honeywell part no. 118367A) is available to
facilitate flame sighting after the C7915A is mounted.
FIELD OF VIEW
A lead sulfide photocell, like other photocells, views an area
rather than a point. It is unable to pinpoint pilot flame location
as easily as a flame rod.
flame, it must view only a part of the flame so it can detect the
pilot only when it is large enough to successfully light the main
burner
. The viewing area must not be so large that a weak and
wavering pilot flame could energize the photocell and cause
the flame relay to pull in.
The area viewed by the photocell depends on:
1. Diameter of the opening in front of the cell.
2. Distance from the cell to the opening.
3. Distance from the opening to the area to be viewed.
Fig. 2 shows three ways of reducing the field of view, assuming
that the distance from the viewing opening to the flame or
refractory cannot be changed. These are (1) lengthening the
sight pipe, (2) reducing the diameter of the sight pipe, and (3)
installing an orifice plate in front of the photocell. Combinations
of these methods can be used.
If the detector is to prove only the pilot
.
When a flame is present, the lead sulfide photocell detects the
infrared radiation generated. The C7915A produces an electric
signal that is sent to the amplifier in the flame safeguard
control. The amplified signal pulls in the flame relay in the
flame safeguard control to allow proper operation.
Because it is necessary for the detector to actually see the
flame, it is best to locate the detector as close to the flame as
physical arrangement, temperature, and other restrictions
permit. These restrictions are described in detail below.
DETERMINE THE LOCATION
Before beginning the actual installation, determine the best
location for mounting the flame detector. Carefully consider the
factors discussed in this section before establishing the
location.
TEMPERATURE
The sensitivity of the lead sulfide cell decreases as its
temperature increases. Up to 125°F (52°C), the loss in
sensitivity is negligible, but temperatures above this point
be avoided
. Under normal temperature conditions (below
125°F (52°C), the life of the lead sulfide cell should be
unlimited. The quickest check for excessive temperature is
simply to grasp the detector—it should not be too hot to hold
comfortably in your bare hand.
Several methods are available for cooling the lead sulfide
photocell including ventilating the sight pipe and installing a
pipe nipple, seal-off adapter, and/or heat block between the
sight pipe and the detector. Refer to Installing Accessories,
page 7.
must
CHANGING PIPE LENGTH OR SIZE
(DIAMETER)
The effect or changing the length of the sight pipe is shown in
Table 2 and 3.
Changing the diameter of the sight pipe is not as simple as
changing the length, because the C7915A mount and
mounting accessories are all sized for 3/4 in. pipe. When the
sight pipe diameter is reduced, the effect is the same as adding
an orifice plate to the pipe as discussed below.
REFRACTORY
DESIRED VIEWING
AREA
UNRESTRICTED VIEW
BY LENGTHENING
(1)
THE SIGHTING PIPE
BY DECREASING THE
(2)
PIPE SIZE (DIAMETER)
BY INSTALLING
(3)
AN ORIFICE PLATE
Fig. 2. Methods of reducing C7915A Detector field-of-view.
M3049C
65-0292-06 4
C7915A INFRARED FLAME DETECTOR
Table 2. Diameter of Area Sighted Through Various Lengths of 3/4-in. Pipe Without Orifice, in inches.
Length of
Pipe—in.
1 6.3 11.9 17.6 23.2 28.4 34.5 Over 40
2 3.5 6.3 9.1 11.9 14.8 17.6 20.4 23.2 26.0 28.9 31.7 34.5
3 2.6 4.4 6.3 8.2 10.1 11.9 12.9 15.7 17.6 19.5 21.3 23.2
4 2.1 3.5 4.9 6.3 7.8 9.1 10.6 11.9 13.4 14.8 16.2 17.6
5 1.8 2.9 4.1 5.2 6.3 7.5 8.6 9.7 10.7 11.9 13.1 14.2
6 1.6 2.6 3.5 4.4 4.3 6.3 7.3 8.2 9.1 10.1 11.0 11.9
7 1.5 2.3 3.1 3.9 4.7 5.5 6.3 7.1 8.0 8.7 9.6 10.4
8 1.4 2.1 2.8 3.5 4.2 4.9 5.6 6.3 7.1 7.7 8.5 9.1
Length of
Pipe-—mm
25.4 160.0 302.3 447.0 589.3 721.4 876.3 Over 1016.0
50.8 88.9 160.0 231.1 302.3 375.9 447.0 518.2 589.3 660.4 734.1 805.2 876.3
76.2 66.0 111.8 160.0 208.3 256.5 302.3 327.7 398.8 447.0 495.3 541.0 589.3
101.6 53.3 88.9 124.5 160.0 198.1 231.1 269.2 302.3 340.4 375.9 411.5 447.0
127.0 45.7 73.7 104.1 132.1 160.0 190.5 218.4 246.4 271.8 302.3 332.7 360.7
152.4 40.6 66.0 88.9 111.8 137.2 160.0 185.4 208.3 231.1 256.5 279.4 302.3
177.8 38.1 58.4 78.7 99.1 119.4 139.7 160.0 180.3 203.2 221.0 243.8 264.2
203.2 35.6 53.3 71.1 88.9 106.7 124.5 142.2 160.0 180.3 195.6 215.9 231.1
6 1218243036424854606672
Table 3. Diameter of Area Sighted Through Various Lengths of 3/4-in. Pipe Without Orifice, in mm.
152.4 304.8 457.2 609.6 762.0 914.4 1066.8 1219.2 1371.6 1524.0 1676.4 1828.8
Distance From End of Pipe To Sighted Area—in.
Distance From End of Pipe To Sighted Area—mm
INSTALLING AN ORIFICE PLATE
An orifice plate with a hexagonal orifice diameter of 0.125 in.
(3.2 mm) is supplied with the C7915A Infrared Flame Detector.
The orifice can be mounted in front of the cell in the seal-off
adapter or in a standard 3/4 in. coupling. (Refer to Fig. 1.)
Table 4. Diameter of Area Sighted Through Orifice, in inches.
Cell To Orifice
Distance (in.)
1 3.2 6.1 8.8 Over 10
2 1.6 3.2 4.6 6.1 7.6 8.8
3 1.1 2.1 3.2 4.2 5.2 6.1
4 Less than 1 1.6 2.4 3.2 3.9 4.6
5 — 1.3 1.9 2.5 3.2 3.8
6 — 1.1 1.6 2.1 2.6 3.2
Cell To Orifice
Distance (mm)
25.4 81.3 154.9 223.5 Over 254.0
50.8 40.6 81.3 116.8 154.9 193.0 223.5
76.2 27.9 53.3 81.3 106.7 132.1 154.9
101.6 Less than 25.4 40.6 61.0 81.3 99.1 116.8
127.0 — 33.0 48.3 63.5 81.3 96.5
152.4 — 27.9 40.6 53.3 66.0 81.3
12 24 36 48 60 72
Table 5. Diameter of Area Sighted Through Orifice, in mm.
12 24 36 48 60 72
Distance From Orifice To Sighted Area—in.
Distance From Orifice To Sighted Area—mm.
The size of the sighted area at various distances can be
determined from Table 4 or 5. For example, if the distance from
the photocell to a 0.125 in. (3.175 mm) diameter orifice is 4 in.
(101.6 mm), and from the orifice to the flame junction (or
refractory) is 36 in. (914.4 mm), the diameter of the sighted
area is 2.4 in. (61 mm).
Fig. 3 shows how a typical orifice plate restricts the view of a
small area around the flame junction.
Orifice Diameter—in.
0.125
Orifice Diameter—in.
0.125
5 65-0292-06
C7915A INFRARED FLAME DETECTOR
M3050B
PILOT HOT REFRACTORY MAIN FLAME
PILOT HOT REFRACTORY MAIN FLAME
WITHOUT ORIFICE PLATE
WITH ORIFICE PLATE
Fig. 3. Using orifice plate to restrict detector field of view to intersection of pilot and main flame,
or to small area of hot refractory.
RESPONSE TO HOT REFRACTORY
Although the infrared amplifier will not respond to steady
radiation, as produced by hot refractory, be careful to protect
the infrared detector from hot refractory radiation because of
two possible conditions,
a. Shimmer—Turbulent hot air, steam, smoke, or fuel
spray in the combustion chamber can reflect, bend,
or block the steady infrared radiation emitted by a hot
refractory. These conditions can change the steady
radiation from a hot refractory into a fluctuating radiation. If these fluctuations occur at the same frequency as that of a flickering flame, they will simulate
flame and will hold in the flame relay after the actual
burner flame has been extinguished.
b. Radiation saturation—Steady hot refractory radiation
can become strong enough to mask the fluctuating
radiation of the flame. This is similar to the effect of
holding up a candle in front of the sun—the light of
the sun is so strong that the candle light cannot be
seen. If radiation saturation is extreme, the flame
relay will drop out, and the system will shut down as
though a flame failure has occurred.
Both of these problems will be minimized by aiming the
detector at a portion of the refractory that is:
• as cool as possible.
• as far from the cell as possible.
• as reduced a field of view as possible, see Fig. 2 and 3.
shimmer
and
radiation saturation
SIGHTING SUMMARY
When sighting the detector, two important factors to consider
are: (1) proper sighting of the flame being detected (normally
the pilot/main flame junction), and (2) avoiding hot refractory
.
sighting.
A typical sighting arrangement is shown in Fig. 4. The detector
is aimed at the intersection of the pilot and main flames, and at
a relatively cool side of the combustion chamber. The detector,
in this case, would be located as close as possible to the
burner to sight the maximum depth of the flame and reduce the
effect of variations in the main flame pattern.
The detector can also be sighted from a point below and close
to the burner with the line-of-sight above the refractory (Fig. 5).
The third method is to aim the detector from above the burner,
sighting a portion of the refractory floor (Fig. 6). This type of
application requires that the pilot flame be carefully sighted
from the side. The detector should not be sighted
shoulder
a pilot too small to satisfactorily light the main flame.
The actual area of hot refractory sighted should be as small as
possible and consistent with proper sighting of the flame. Refer
to Fig. 2 and 3 for methods of reducing the area of hot
refractory sighted.
over the
of the pilot because the chances increase of sighting
Refractory temperatures in the combustion chamber will vary
with combustion chamber design, but generally the end wall of
the chamber will be the hottest point. It will normally be best to
aim the detector at the side wall of the refractory (Fig. 4), at a
point above the refractory (Fig. 5), or at the floor of the
combustion chamber (Fig. 6).
65-0292-06 6
Fig. 4. C7915A Infrared Flame Detector aimed at side wall of
M23454A
C7915A SIGHTING
TOWARD SIDE WALL
INTERSECTION OF
PILOT AND MAIN FLAME
MAIN BURNER FLAME
REFRACTORY WALL
AREA VIEWED BY C7015A
BURNER
FACEPLATE
CENTER LINE
M23455A
C7915A
SIGHTING
UPWARD
INTERSECTION OF
PILOT AND MAIN FLAME
MAIN BURNER FLAME
DETECTOR VIEWS AREA
ABOVE THE REFRACTORY
BURNER
FACEPLATE
CENTER LINE
M23457A
C7915A SIGHTING
DOWNWARD (MUST
BE OFF TO THE SIDE)
INTERSECTION OF
PILOT AND MAIN FLAME
MAIN BURNER FLAME
REFRACTORY FLOOR
AREA VIEWED BY C7915A
BURNER
FACEPLATE
CENTER LINE
DETECTOR PIPE NIPPLE PIPE TEE SIGHTING
PIPE
COOLING AIR
APPLIED UNDER PRESSURE
M3047B
combustion chamber.
C7915A INFRARED FLAME DETECTOR
CLEARANCE
Make sure there will be enough room to easily mount the sight
pipe, flame detector, and all required accessories, and to
remove the flame detector for troubleshooting and servicing.
INSTALLING THE SIGHT PIPE
The location of the sight pipe is the most critical part of the
installation. A 3/4 in. black iron sight pipe is recommended. Do
not use a stainless steel or galvanized pipe because its internal
surface blackens with use as deposits from the combustion
chamber accumulate on it. Initially, its shiny internal surface
reflects infrared radiation, which could result in a satisfactory
flame signal even though the pipe may be improperly located.
As it blackens, less infrared radiation is reflected and the flame
signal becomes marginal.
Because no two situations are the same, the 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.
PREPARE HOLE IN WALL OF
COMBUSTION CHAMBER
Form a hole of the proper diameter for the sight pipe in the wall
of the combustion chamber at the selected location. Flare the
hole (Fig. 9) to leave room for small adjustments of the sighting
angle. The taper of the hole should be about 1 in. for every 3 in.
(25.4 mm for every 76.2 mm) of wall thickness.
Fig. 5. C7915A Infrared Flame Detector
aimed at a point above refractory.
Fig. 6. C7915A Infrared Flame Detector
aimed at floor of combustion chamber.
INSTALLING ACCESSORIES
It may be necessary or desirable to install accessories
between the sight pipe and the detector. This section describes
the installation of these accessories.
SIGHT PIPE VENTILATION
It may be necessary to ventilate the sight pipe to cool the
detector.
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 into the chamber. A perforated pipe nipple between
the sight pipe and the flame detector can also be used. See
Fig. 7.
For a positive pressure combustion chamber, connect a supply
of pressurized air from the burner blower to flow through the
sight pipe into the chamber. The air pressure must be greater
than the chamber pressure.
Fig. 7. Forced air cooling.
7 65-0292-06
C7915A INFRARED FLAME DETECTOR
CAUTION
FLEXIBLE
METAL CABLE
SHIELD LEADWIRES
PHOTOCELL
SOCKET
PLUG-IN LEAD SULFIDE CELL
(PART NO. 32007255-001)
BUSHING
MOUNTING
COLLAR
CAP
M23449A
FOCUSING LENS
SWIVEL MOUNT
To facilitate flame sighting, a Swivel Mount (part no. 118367A)
is available. The Swivel Mount requires a reducer of the proper
size to mount it onto the sight pipe. (For mounting details, refer
to form 60-0361 for the 118367A Swivel Mount.)
REDUCER BUSHING
To mount the detector on a 1/2 in. sight pipe,
replacing a Fireye™ lead sulfide detector
Reducer Bushing (Fig. 1).
specifically if
, install a 390427A
ORIFICE PLATE
To reduce the detector field-of-view, and restrict it to the
intersection of the pilot and main flame, or to a small area of
hot refractory (see Fig. 3), install a 105134 Orifice Plate. The
orifice plate can be inserted into a standard 3/4 in. pipe
coupling (Fig. 1) or into the seal-off adapter, if used.
MOUNTING SIGHT PIPE
Thread one end of the pipe to fit the mounting collar on the
detector (or an accessory, if used, see Fig. 1). Cut the pipe to
the desired length (as short as practical).
To avoid conducting
excessive heat back to the lead sulfide photocell, the sight pipe
should not extend more than halfway into the refractory
weld the pipe to the wall in a trial position (Fig. 9).
. Tack
Do not
permanently weld the sight pipe in place until after completing
the Adjustments and Checkout, page 10.
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.
PIPE NIPPLE
A 3/4 in. pipe nipple, 6 to 8 in. (152 to 203 mm) long, can be
inserted between the sight pipe and the C7915A Mount (Fig. 1)
to help cool the lead sulfide cell. Using the pipe nipple will also
reduce the viewing area of the detector (see Table 4 or 5).
SEAL-OFF ADAPTER
To protect the detector from hot gases, install a 105172A SealOff Adapter (Fig. 1). The adapter has a glass window that
prevents hot gases from reaching the lead sulfide photocell.
Mount the C7915A Detector onto the sight pipe, heat block, or
other accessory (Fig. 1 and 9). Screw the mounting collar onto
the sight pipe or accessory.
Fig. 8. Installing lead sulfide photocell.
COMBUSTION
CHAMBER WALL
PILOT
TEMPORARY
TACK WELD
ORIFICE PLATE
IN PIPE COUPLING
SEAL-OFF
ADAPTER
HEAT
BLOCK
C7915A
TO JUNCTION
BOX OR SUBBASE
3/4 INCH
PIPE
NIPPLE
REFRACTORY
FLARED HOLE
3/4 INCH BLACK
IRON SIGHTING PIPE
MAIN FLAME
M23458A
Fig. 9. Mounting C7915A Infrared Flame Detector (and
accessories).
WIRING
HEAT BLOCK
To insulate the detector from sight pipe temperatures above
125°F (52°C), install a 105061 Heat Block (Fig. 1). The device
is made of non–heat-conductive, laminated plastic that
prevents heat from being conducted from the sight pipe to the
detector. It can withstand temperatures up to 250°F (121°C).
MOUNTING THE DETECTOR
Before mounting the C7915A, install the lead sulfide photocell
(if not installed already).
Unscrew the bushing from the cap, plug the photocell into the
cell mount, and screw the bushing back into the cap (Fig. 8).
The bushing also includes a focusing lens to concentrate
available radiation on the photocell face.
65-0292-06 8
Electrical Shock Hazard.
Disconnect power supply before beginning installation
to prevent electrical shock and equipment damage,
there may be more than one disconnect involved.
NOTICE
Per industry standards, a conduit seal or a cable type that is
sealed is required to be installed in a device that can result in
flammable gas or flammable liquid flow through a conduit or
cable to an electrical ignition source in the event of a seal
leakage or diaphragm failure.
1. All wiring must comply with applicable electrical codes,
ordinances, and regulations. Use NEC Class 1 wiring.
2. Keep the coaxial cables from the flame detector to the
flame safeguard control subbase as short as possible.
Capacitance increases with coaxial cable length, reducing the signal strength. The maximum permissible coaxial cable length is fifty feet.
The ultimate limiting factor in
coaxial cable length is the flame signal current/voltage
Refer to Table 6, Adjustments and Checkout, page 10.
3. The detector comes with 30, 48, or 96 in. (0.76, 1.22, or
2.44 m) coaxial cable inside a flexible metal cable. The
coaxial cable is terminated with two leads—one blue and
one white. The coaxial cable is rated for 194°F (90°C).
The cable protects and electrically shields the coaxial
cables.
4. If the coaxial cables are not long enough to reach the terminal strip or wiring subbase, make the required splices
in a junction box (see IMPORTANT below).
5. If splicing is necessary, use moisture-resistant no. 14
wire suitable for at least 167°F (75°C) if the detector is
used with a flame safeguard
primary
control, or at least
194°F (90°C) if used with a flame safeguard programming control.
6.
For splicing in high temperature installations
, use Honeywell specification no. R1298020 or equivalent for the F
coaxial cable. (This wire is rated up to 400°F [204°C] for
continuous duty. It is tested for operation up to 600 volts
and breakdown up to 7500 volts.) For the other coaxial
cable, use moisture-resistant no. 14 wire selected for a
temperature rating above the maximum operating temperature.
IMPORTANT:
1. Flame detector coaxial cables must be as short as
possible. The maximum coaxial cable length from the
flame detector to the flame safeguard control is 50 ft
(15.2 m).
2. Extensions to the flame detector coaxial cables must
be run alone in either rigid or flexible metal conduit.
When flame detector coaxial cables exit a conduit,
they must be as short as possible, twisted, and not be
included in bundles or channels that contain other
wires. Rigid metal conduit is preferred when flame
detector coaxial cables are extended but flexible
metal conduit may be used if it is supported to minimize movement.
3. The flame detector flexible cable shield must be
grounded to the flame safeguard control subbase
either directly or through the metal cabinet/conduit
system that contains the flame safeguard control subbase and flame detector coaxial cables.
4. When flame detector coaxial cables are routed
through junction boxes, identify the junction boxes
with the pressure-sensitive labels provided with the
flame detector (form 96-610).
5. UNDERWRITERS LABORATORIES INC. REQUIRES
THAT THE JUNCTION BOX BE MARKED TO INDICATE THAT NO OTHER WIRING CONNECTIONS
CAN BE ROUTED THROUGH IT. APPLY CAUTION
STICKER (FORM 96-610, FURNISHED) TO THE
JUNCTION BOX.
6. Maximize the separation between ignition transformer
high voltage wires and the flame sensor wires to avoid
ignition interference.
C7915A INFRARED FLAME DETECTOR
C7915A
ASSEMBLY
FLEXIBLE CABLE (MECHANICALLY
SUPPORT TO MINIMIZE MOVEMENT)
.
GROUNDING
STRAP
2
1
1 BLUE WIRE AND 1 WHITE WIRE FROM THE C7915, CONNECT TO
FLAME SAFEGUARD CONTROL'S SUBBASE, KEEP WIRES AS SHORT
AS POSSIBLE, AND TWIST THEM.
2
FLEXIBLE CABLE MUST BE RIN TO FLAME SAFEGUARD CONTROL'S
SUBBASE AND GROUNDED WHERE THE EXPOSED WIRES BEGIN.
WIRING SUBBASE
OR TERMINAL STRIP
BLUE
WHITE
F
1
G
M23446A
Fig. 10. Typical wiring of C7915A Infrared Flame Detector to
nearby wiring subbase or terminal strip.
FLEXIBLE CABLE (MECHANICALLY
SUPPORT TO MINIMIZE
MOVEMENT)
BX CABLE, SHIELDED CABLE,
OR TWISTED PAIR; MUST BE
CONDUIT
FITTING
1
JUNCTION BOX
1
1 BLUE WIRE AND 1 WHITE WIRE FROM THE C7915; CONNECT
INSIDE JUNCTION BOX; LEADWIRES FROM JUNCTION BOX NEED
TO BE POLARIZED.
2
APPLY CAUTION STICKER, FORM NO. 96-610 SUPPLIED WITH
C7915, TO THIS JUNCTION BOX. BOX MUST BE GROUNDED.
3
USE RIGID CONDUIT, OR SUPPORT FLEXIBLE CONDUIT TO
MINIMIZE MOVEMENT.
4
CONDUIT MUST BE RUN TO FLAME SAFEGUARD CONTROL'S
SUBBASE AND GROUNDED THERE. KEEP EXPOSED WIRES AS
SHORT AS POSSIBLE AND TWIST THEM.
3
2
ALONE IN CONDUIT.
4
C7915A
ASSEMBLY
FLAME SAFEGUARD
CONTROLS SUBBASE
F
G
M23447B
Fig. 11. Typical wiring of C7915A Infrared Flame Detector to
distant wiring subbase or terminal strip.
9 65-0292-06
C7915A INFRARED FLAME DETECTOR
ADJUSTMENTS AND
CHECKOUT
IMPORTANT:
Before welding the sight pipe in its final location, complete the Adjustments and Checkout Tests below and
any tests required by the burner manufacturer.
ADJUST DETECTOR SIGHTING
POSITION
For initial burner light off, consult the burner manufacturer
instructions or flame safeguard control instructions.
With the flame detector installed and the burner running, adjust
the sighting position of the detector for optimum flame signal.
Refer to Table 6 for the minimum acceptable flame signal for
the amplifiers and associated flame safeguard controls.
The R7852B (AMPLI-CHECK™) amplifiers have a dc voltage
flame signal output.
To measure the flame signal voltage when using R7852A,B
amplifiers, a volt-ohm meter with a minimum sensitivity of one
megohm/volt is recommended. The flame signal (voltage)
measurements are made as shown in Fig. 12. The positive
(red) meter lead is connected to the positive (+) control jack
and the negative (black) meter lead to the negative (-)
-Com jack. If the 7800 SERIES, R7140 controls have the
Keyboard Display Module, a zero to five Vdc voltage is
displayed on the module. Refer to Table 6 for minimum and
maximum flame voltages.
Move the detector and sight pipe around to sight the flame at
various positions and angles. Try to get a maximum steady
meter reading. The signal must be above the minimum
acceptable current/voltage listed in Table 6.
Measure the flame signal for the pilot alone, the main burner
flame alone, and both together (unless monitoring only the pilot
flame when using an intermittent pilot, or only the main burner
flame when using direct spark ignition). Also measure the
flame signal at high and low firing rates and while modulating in
between (as applicable). With the detector in its final position,
all required flame signals must be steady and as specified in
Table 6. If you cannot obtain the proper signals, refer to the
Troubleshooting section.
POSITIVE (+)
METER LEAD
NEGATIVE (–)
METER LEAD
Fig. 12. Measuring 7800 SERIES, R7140 Flame Safeguard
Control flame signal voltage.
ONE MEGOHM/VOLT
METER
M7382A
Table 6. Flame Signal.
Flame Signal Amplifier Flame Safeguard Control
R7852A RM7800E,G,L,M; RM7823A; RM7838A,B,C;
R7852B AMPLI-CHECK™ 1.25 5.0
PILOT TURNDOWN TEST
If the detector is used to prove a pilot flame before the main
fuel valve can be opened, perform a Pilot Turndown Test before
welding the sight pipe into position. Follow the procedures in
the instructions for the appropriate flame safeguard control,
and the burner manufacturer instructions.
HOT REFRACTORY SATURATION
TEST
Test to be sure radiation from hot refractory does not mask the
flickering radiation of the flame itself.
RM7840E,G,L,M; RM7885A; RM7890A,B;
RM7895A,B,C,D; RM7896; RM7897;
RM7898; R7140
Start the burner and monitor the flame signal during the
warmup period. A decrease in signal strength as the refractory
heats up indicates hot refractory saturation. If saturation is
extreme, the flame signal will decrease to a point that the
system will shut down as though a flame failure has occurred.
If hot refractory saturation occurs, the condition must be
corrected. Add an orifice plate in front of the photocell to
restrict the viewing area. If this does not work, resight the
detector at a cooler, more distant background. Lengthening the
sight pipe or decreasing the pipe size (diameter) may also be
helpful. Continue adjustments until hot refractory saturation is
eliminated.
Minimum Acceptable
Steady Voltage (Vdc)
1.25 5.0
Maximum Expected
Voltage (Vdc)
65-0292-06 10
C7915A INFRARED FLAME DETECTOR
CAUTION
CAUTION
HOT REFRACTORY HOLD-IN TEST
Test to make certain that hot refractory will not cause the flame
to remain after the burner flame is extinguished. This condition
would delay response to flame failure and also would prevent a
system restart as long as the infrared radiation emitted by the
hot refractory is detected.
First check the plug-in flame signal amplifier by initiating a
burner cycle. When the system is in the
the firing cycle while the refractory is at a low temperature.
Measure the time it takes for the flame signal LED to go out
after the flame goes out. If the flame signal LED fails to go out
within four seconds, open the master switch and replace the
amplifier.
Infrared detectors can respond to infrared radiation emitted by
a hot refractory, even when the refractory has visibly ceased to
glow. Infrared radiation from a hot refractory is steady, whereas
radiation from a flame has a flickering characteristic. The
infrared detection system responds only to a flickering infrared
radiation; it can reject a steady signal from hot refractory.
However, the refractory’s steady signal can be made to
fluctuate if it is reflected, bent, or blocked by smoke or fuel mist
within the combustion chamber. Be careful when applying an
infrared system to ensure its response to flame only.
To check a C7915A Infrared Flame Detector
hold-in, operate the burner until the refractory reaches its
maximum temperature. If the installation has a multifuel burner,
burn the fuel most likely to reflect, bend, or obscure the hot
refractory’s steady infrared radiation (burn solids instead of
liquids, or liquids instead of gases). When the maximum
refractory temperature is reached, close all manual fuel shutoff
valves or open the electrical circuits of all automatic fuel valves.
Visually observe when the burner flame goes out. After the
flame goes out, measure the time it takes for the flame signal
LED to go out. If the flame signal LED fails to go out within four
seconds, the infrared detector is sensing the radiation from hot
refractory. Immediately terminate the firing cycle (lower the set
point of the burner controller, or set the fuel selector switch to
OFF). Do not open the master switch.
run
position, terminate
for hot refractory
suppresses electrical noise (such as the type of cable used in
automobiles). Maintain maximum separation of flame sensor
and ignition wiring.
To determine if an infrared flame amplifier responds to ignition
interference, complete the following test sequence:
1. CLOSE MANUAL FUEL VALVES TO THE PILOT AND
MAIN BURNER.
2. Connect a flame signal meter to the amplifier and start
the burner.
3. There should be no flame signal when the ignitor is energized (momentary meter movement may be observed
when the flame safeguard control switches a load on or
off).
WELD THE SIGHT PIPE
After adjustments have been made and an acceptable flame
signal obtained, remove the detector and weld the sight pipe in
its final position (if you are using a swivel mount, the pipe may
already be welded). Then reinstall the detector.
FINAL CHECKOUT
Before putting the burner into service, check out the installation
by using the Checkout procedures in the instructions for the
appropriate flame safeguard control. After completing the
checkout, run the burner through at least one complete cycle to
verify proper operation.
Complete Checkout Tests.
Do not put the system into operation until all Checkout
tests in the instructions for the appropriate flame
safeguard control and any specified in the burner
installation instructions are satisfactorily completed.
TROUBLESHOOTING
NOTE: Some burners continue to purge their oil lines
If the detector is sensing hot refractory radiation
must be corrected. Add an orifice plate in front of the photocell
to restrict the detector viewing area. If this does not work,
resight the detector at a cooler, more distant part of the
combustion chamber. While resighting the detector, remember
that it must also properly sight the flame. Lengthening the sight
pipe or decreasing the pipe size (diameter) may also be
helpful. For details, refer to Installation. Continue adjustments
until hot refractory hold-in is eliminated.
between the valves and nozzles even though the fuel
valve(s) is closed. Terminating the firing cycle
(instead of opening the master switch) will allow purging of the combustion chamber. This will reduce a
buildup of fuel vapors in the combustion chamber
caused by oil line purging.
, the condition
IGNITION INTERFERENCE TEST
It is possible for infrared amplifiers to respond to ignition spark
electrical noise (interference) under certain conditions. Avoid
ignition interference by locating the transformer as close as
possible to the burner ignition electrode (preferably not on the
control cabinet). You can also use an ignition cable that
Electrical Shock Hazard. Be extremely careful while
troubleshooting the detector; line voltage is present on
some of the terminals on the wiring subbase or
terminal strip when power is on. Open the master
switch to disconnect power before removing or
installing the detector, there may be more than one
disconnect involved.
If you cannot obtain a satisfactory flame signal while adjusting
the sighting position of the detector, follow these procedures. If
you encounter other problems in the system, refer to
Troubleshooting in the instructions for the appropriate flame
safeguard control.
EQUIPMENT REQUIRED
1. Voltmeter (Honeywell W136A or equivalent) with 0 to 300
Vac scale.
2. A one megohm/volt meter with a zero to 5 or 10 Vdc
scale is recommended for 7800 SERIES, R7140 control
flame voltage measurements. If the control has the Keyboard Display Module option, flame voltage is displayed
on the module.
3. Replacement parts—see Specifications.
11 65-0292-06
C7915A INFRARED FLAME DETECTOR
CAUTION
TROUBLESHOOTING PROCEDURES
First perform the Preliminary Inspection. Then follow the
applicable procedures for either a low reading or a zero
reading on the flame signal meter. After reinstalling the
detector, recheck the meter reading. Adjust the position of the
detector to try to obtain the proper flame signal. If the
procedures are completed and a satisfactory flame signal
cannot be obtained, replace the detector.
PRELIMINARY INSPECTION
1. Make sure that the flame is properly adjusted and is not
too lean.
2. Check for the proper line voltage. Make sure the master
switch is closed, connections are correct, and power
supply is of the correct voltage and frequency.
3. Check the detector wiring for defects including:
• incorrect connections.
• wrong type or size of wire.
• deteriorated wire.
• open circuits.
• short circuits.
• leakage paths caused by moisture, soot, or dirt.
4. With the burner running, check the temperature at the
detector. If it exceeds 125°F (52°C):
• add additional insulation between the wall of the
combustion chamber and the detector.
• add a shield or screen to reflect radiated heat away
from the detector.
• add cooling (refer to Sight Pipe Ventilation, see
Installation).
6. If you still cannot obtain a proper flame signal, replace
the C7915A Infrared Flame Detector.
PROCEDURE FOR A ZERO METER
READING
1. Replace the lead sulfide cell (Fig. 8). Then recheck the
flame signal.
2. If there is still no flame signal, replace the plug-in amplifier.
3. If you still cannot obtain a meter reading, replace the
entire C7915A Infrared Flame Detector.
IMPORTANT:
At the completion of troubleshooting, be sure to perform the Adjustments and Checkout, page 10.
SERVICE
Fire and Explosion Hazard. Only use qualified service
technicians to attempt to service or repair flame
safeguard controls and burner systems.
Open the master switch to disconnect power before
removing or installing the detector.
If the C7915A is disassembled for any reason (e.g., to
replace the lead sulfide cell or bushing with focusing
lens), you must perform the Adjustments and
Checkout, page 10.
PROCEDURE FOR A LOW METER
READING
1. Remove the detector and clean the focusing lens with a
soft, clean cloth.
2. If the focusing lens is broken or damaged, or if it is
coated with a substance that cannot be cleaned off,
replace the 50019469-001 Bushing (which includes the
focusing lens).
3. Clean the inside of the sight pipe before reinstalling the
detector.
4. If the meter reading is still too low, replace the lead sulfide cell (Fig. 8).
5. If the meter reading is still too low, replace the plug-in
amplifier.
PERIODIC MAINTENANCE
1. Clean the focusing lens and sight pipe when necessary.
Remove the detector and use a soft, clean cloth. The
lens does not require removal to clean it. If it is broken
or damaged, or it is coated with a substance that cannot
be cleaned off, replace the 50019469-001 Bushing,
which includes the focusing lens.
2. Keep the flame detection system adjusted for the
smoothest, most reliable operation as recommended by
the burner manufacturer.
3. Replace the bushing with focusing lens or the lead sulfide photocell (Fig. 8)
proper operation
only when necessary to obtain
.
Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
customer.honeywell.com
® U.S. Registered Trademark
© 2012 Honeywell International Inc.
65-0292-06 JPG 09-12
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