Honeywell Carbon Monoxide Alarm C7035 User Manual

C7027A, C7035, C7044A, C7927A  
Minipeeper® Ultraviolet Flame Detectors  
PRODUCT DATA  
C7044A may also be used with the following 50 Hz  
Honeywell combustion controls/amplifiers:  
R4341/R7323  
R4343/R7323  
R4344/R7323  
C7027A  
C7027A has an integral collar threaded (internal  
1/2-14 NPSM) for mounting on a one-half-inch sight  
pipe.  
C7035A  
C7035A has an integral collar threaded (internal  
1-11-1/2 NPSM) for mounting on a one-inch sight pipe.  
C7035A housing meets Underwriters Laboratories Inc.  
requirements for rain tightness and complies with  
NEMA enclosure standards, types 4 and 4X.  
C7044A  
C7044A mounts with a two screw bracket. The UV  
sensor tube is enclosed in a stainless steel housing.  
C7927A  
C7044A has the capability of side or end viewing in  
flame monitoring applications.  
Because of their compact size, the C7027A and  
C7044A are particularly suitable for blast tube  
mounting.  
APPLICATION  
The C7027A, C7035A, C7044A and C7927A Minipeeper®  
Ultraviolet Flame Detectors detect the ultraviolet radiation  
emitted by combustion flames. The flame detectors are used  
with Honeywell flame safeguard controls to provide flame  
supervision for gas, oil, or combination gas-oil burners.  
Properly installed, the C7027A, C7035A and C7927 are  
pressure rated for 5 psi.  
C7035A ultraviolet radiation sensor tube is field  
replaceable.  
Two C7027A, C7035A or C7044A Flame Detectors can  
be wired in parallel for difficult flame sighting  
installations.  
FEATURES  
C7927A is used with only the R7851B Flame Amplifier  
and the 7800 SERIES controls.  
C7027A, C7035A, and C7044A Flame Detectors are  
used with RA890G devices or R7249A, R7290A,  
R7749B and R7849A,B Amplifiers and the appropriate  
Honeywell controls.  
C7927A has an integral collar threaded (internal  
1/2-14 NPSM) for mounting on a one-half inch sight  
pipe.  
Contents  
Ordering Information ........................................................  
2
® U.S. Registered Trademark  
Copyright © 2001 Honeywell • All Rights Reserved  
60- 2026- 11  
 
   
C7027A, C7035, C7044A, C7927A MINIPEEPER® ULTRAVIOLET FLAME DETECTORS  
Dimensions: See Fig. 2.  
C7035A Minipeeper® Ultraviolet  
Flame Detector:  
Replacement Parts:  
129808 Flange Gasket.  
129464M Ultraviolet Sensing Tube, 0°F to 250°F  
(-18°C to +121°C).  
129464N Ultraviolet Sensing Tube, -40°F to +250°F  
(-40°C to 121°C).  
Flame Detection: End viewing.  
Ambient Operating Temperature Ratings: 0°F to 250°F  
(-18°C to +121°C), or -40°F to 250°F (-40°C to +121°C),  
depending on model.  
C7027A, C7035A AND C7044:  
Approvals:  
Maximum Pressure Rating: 5 psi (34.5 kPa).  
Underwriters Laboratories Inc. listed: File No. MP268.  
Canadian Standards Association certified:  
Master Report LR 95329-1.  
Mounting: Collar with 1-11-1/2 NPSM internal threads for  
mounting on a 1 in. sight pipe. (The DIN approved  
C7035A1064 has 1-11 BSP.P1 threads.)  
Factory Mutual approved.  
Industrial Risk Insurers acceptable.  
DIN approved models: C7027A1056, C7035A1049,  
C7035A1064.  
Wiring Connections: Two 6 ft. [1.83 m], color-coded  
NEC Class 1 leadwires rated for 302°F (150°C). One  
model is available with 12 ft. (3.66 m) leadwires.  
Rear of detector has 1/2-14 NPSM internal threads for  
connecting to a conduit. The DIN-approved C7035A1064  
has 1/2-14 BSP-F threads.  
General Accessories:  
118367A Swivel Mount; provides adjustable positioning of  
the C7027A or C7035A.  
204342 Ultraviolet mirror, 3/4 in. NPT.  
105172C Seal off adapter, 3/4 in. NPT.  
C7035A1056 has 12 ft (3.66 m) leadwires.  
C7035A1080 leadwire is rated for 600°F (204°C).  
6 FOOT [1.83 METER]  
LEADWIRES (2)  
MOUNTING BRACKET  
3/8  
(10)  
7/8  
(22)  
9/16  
(14)  
1/2  
(13)  
1-27/64  
(36)  
3-5/8 (92)  
C7044  
Fig. 3. Installation dimensions of C7044A in in. (mm).  
M1944B  
C7044A Minipeeper® Ultraviolet  
Flame Detector:  
C7927A Minipeeper® Ultraviolet  
Flame Detector:  
Flame Detection: Housing has two openings to permit either  
side or end viewing. Side viewing is 1/8 as sensitive as end  
viewing.  
Ambient Operating Temperature Ratings:  
C7927A1016 (U.S. Version): -40°F to +200°F  
(-40°C to +93°C).  
C7927A1008 (European Version): -4°F to +140°F  
(-20°C to +60°C).  
Mounting: Bracket (included in 4074BVK Bag Assembly),  
secured by two 8-32 RHIS (European M-4) screws (not  
included).  
Storage Temperature Rating: -20°F to +120°F  
(-28°C to +49°C).  
Wiring Connections: Two 6 ft. (1.83 m) color-coded NEC  
Class 1 leadwires. Rear of detector has a clamp type  
connector for 1/2 in. flexible metallic conduit.  
Maximum Pressure Rating: 5 psi 34.5 kPa).  
Mounting: Collar with 1/2-14 NPSM internal threads for  
mounting on a 1/2 in. (13mm) sight pipe.  
Dimensions: See Fig. 3.  
Wiring Connections: Two four-foot (1.2 meter) color-coded  
NEC Class 1 leadwires. Rear of detector has a clamp-type  
connector for 1/2 in. (13mm) flexible metal conduit.  
Dimensions: See Fig. 4 and 5.  
Approvals:  
Underwriters Laboratories Inc. (cUL), MP268, Volume 30.  
Factory Mutual (FM): Pending.  
3
60-2026—11  
 
C7027A, C7035, C7044A, C7927A MINIPEEPER® ULTRAVIOLET FLAME DETECTORS  
1 (25)  
4 FOOT (1.2 METER)  
LEADWIRES (2)  
3-3/4 (95)  
3-1/4 (82)  
1
(25)  
3-11/16  
(94)  
C7927A1016  
M17783  
6-1/2 FT. (1.98M)  
M17784  
C7927A1008  
Fig. 4. Installation dimensions of C7927A1016 (U.S.A. version) and C7927A1008 (European version) in in. (mm).  
IMPORTANT  
INSTALLATION  
Ultraviolet radiation sensing tubes have a life  
expectancy of 40,000 hours of continuous use within  
the flame detector's specified ambient temperature  
and voltage ratings. Wearout of an ultraviolet  
radiation sensing tube results in failure of the UV  
sensor to properly discriminate between flame  
conditions.  
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 technician.  
The C7027A, C7035A and C7044A Flame Detectors  
should only be used on burners that cycle on/off  
periodically or, in the absence of cycling, are  
periodically checked for proper operation.  
4. After installation is complete, check out product  
operation as provided in these instructions.  
Disconnect power supply before beginning installation to  
prevent electrical shock and equipment damage. All wiring  
must comply with applicable electrical codes, ordinances  
and regulations. Use NEC Class 1 wiring.  
Recommended industry standards for the frequency  
of sensor checks, either through cycling (employing  
safe-start check methods) or periodic maintenance,  
vary between once every ten seconds and once  
every week, depending on the standard used and  
the application needs.  
Consult the equipment manufacturer or the  
governing standard for recommendations about  
frequency of checks.  
Controls incorporating safe-start checks, and  
sensors and controls employing constant check  
means are available from Honeywell. See your  
Honeywell representative for specific information.  
60-2026—11  
4
 
C7027A, C7035, C7044A, C7927A MINIPEEPER® ULTRAVIOLET FLAME DETECTORS  
Other Radiation Sources Sensed  
By The UV Detector  
WARNING  
Explosion Hazard and Electrical Shock Hazard.  
Can cause serious injury, death or property  
damage.  
Examples of radiation sources (other than flame) that could  
actuate the detection system are:  
1. Ultraviolet Sources:  
1. The C7027A, C7035A , C7044A and C7927 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.  
a. Hot refractory above 2800°F (1371°C).  
b. Spark.  
c. Ignition transformers.  
d. Welding arcs.  
e. Lightning.  
f. Gas lasers.  
g. Sun lamps.  
h. Germicidal lamps.  
2. Gamma Ray and X-ray Sources:  
a. Diffraction analyzers.  
3. Read the installation instructions before starting the  
installation.  
b. Electron microscopes.  
c. Radiographic X-ray machines.  
d. High voltage vacuum switches.  
e. High voltage condensers.  
f. Radioscotopes.  
4. All wiring must be NEC Class 1 (line voltage).  
5. The flame detector must be positioned so that it  
sights the flame and does not respond to the UV  
radiation emitted by sparks generated by a spark  
ignitor. The Q624A Solid-State Igniter may be useful  
in difficult installations.  
Except under unusual circumstances, none of these sources  
except hot refractory and ignition spark would be present in or  
near the combustion chamber.  
The detector may respond to hot refractory above 2800°F  
(1371°C) if the refractory surface represents a significant  
percentage of the field of view of the detector. If the  
temperature of the hot refractory causes the flame relay  
(in the flame safeguard control) to pull in, re-position the sight  
pipe so the detector views a cooler area of the refractory.  
Basic Requirements For Ultraviolet  
Detector Installations  
All flames emit ultraviolet radiation, invisible to the human eye  
but detected by the UV sensing tube. There are two important  
factors in UV detector installation:  
Ignition spark is a source of ultraviolet radiation. When  
installing the C7027A, C7035A, C7044A or C7927 Flame  
Detector, make sure it does not respond to ignition spark (see  
Ultraviolet Response Test, page 9.) If the installation is such  
that response to the ignition sparks cannot be avoided, the  
Q624A Solid-State Ignition Transformer may eliminate the  
ignition spark response. The Q624A, when properly installed,  
prevents C7027A, C7035A, C7044A and C7927 ignition  
spark response by alternately activating the spark generator  
and the UV sensing tube.  
The detector must have a line-of-sight view of the flame.  
The detector must not be exposed to other sources of  
ultraviolet radiation, the most common being ignition spark.  
Other sources are listed in the next section.  
Because it is necessary for the detector to actually see the  
flame, it is desirable to 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, page 9).  
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.  
5
60-2026—11  
 
C7027A, C7035, C7044A, C7927A MINIPEEPER® ULTRAVIOLET FLAME DETECTORS  
Mounting The Sight Pipe (Fig. 6)  
Mounting a C7027A, C7927 or C7035A  
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 beginning on  
page 7.  
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 its internal surface  
blackens with use as deposits from the combustion chamber  
settle on it. Initially, its shiny internal surface reflects ultraviolet  
radiation, which could result in a satisfactory flame signal,  
even though the pipe may be improperly located. As it  
blackens, less ultraviolet radiation is reflected and the flame  
signal may become marginal.  
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.  
Under optimum sighting conditions, the C7027A , C7927 and  
C7035A Flame Detectors can detect most common gas and  
oil combustion flames at a distance of six feet. 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.  
TEMPORARY  
TACK WELD  
FLARED HOLE  
BLACK IRON  
SIGHT PIPE  
Use 1/2 in. pipe for a C7027 or C7927, and 1 in. pipe for  
a C7035. 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.  
REFRACTORY  
BOILER  
PLATE  
M3019A  
Fig. 5. Mounting sight pipe.  
If a C7027A or C7927A 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.  
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 substances such as smoke, excessive moisture or,  
in some instances, unburned fuel.  
In locations where water is usually sprayed on the body of the  
detector, use a C7035A. Internal threads in its base permit the  
use of waterproof flexible conduit for this type of application.  
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. 7).  
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 in. for every 3 in.  
(25 mm for every 76 mm) of wall thickness.  
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 than the chamber pressure.  
60-2026—11  
6
 
C7027A, C7035, C7044A, C7927A MINIPEEPER® ULTRAVIOLET FLAME DETECTORS  
Swivel Mount  
To facilitate proper sighting of the flame, a swivel mount  
(part no. 118367A) is available. The swivel mount will require  
a 3/4 to 1/2 in. reducer and a 1/2 in. close nipple to mount a  
C7027A, or a 1 in. pipe at least 2-1/2 in. [63.5 mm] long to  
mount a C7035A. For mounting details, refer to form 60-0361  
for the 118367A Swivel Mount.  
C7027A (OR C7035A)  
FLANGE  
GASKET  
Mount The Detector (Fig. 7)  
ADD PIPE TEE,  
PERFORATED  
NIPPLE, OR OTHER  
SUITABLE DEVICE  
FOR VENTILATION,  
IF REQUIRED.  
Mount the detector onto the sight pipe, pipe tee, nipple, or  
other fitting. Make sure the flange gasket is in place inside the  
mounting collar on the detector, and then screw the collar onto  
the sight pipe or fitting.  
BLACK IRON  
SIGHT PIPE  
COMBUSTION  
CHAMBER  
WALL  
NOTE: If a window is installed between the UV detector and  
the flame, it must be fabricated from quartz or fused  
silica. Ordinary glass filters out ultraviolet radiation.  
Using a Heat Block With a C7027 (Fig. 8)  
If the temperature of the sight pipe will become high enough to  
cause the C7027A to overheat (above 215°F (102°C) up to  
266°F (130°C), screw a 136733 Heat Block (order separately)  
onto the sight pipe before mounting the detector.  
M3021  
Fig. 6. Mounting a C7027A or C7927A on a  
combustion chamber (viewed from above).  
C7035A mounting is similar.  
136733 HEAT BLOCK  
5
8
1
[41]  
C7027A DETECTOR  
5
8
[16]  
9
16  
[14]  
4 [102]  
1/2-INCH SIGHT PIPE  
1
4
1
16  
[27]  
1
1
[32]  
1/2-14 NPSM  
INTERNAL  
THREADS  
1/2-14 NPSM  
EXTERNAL  
THREADS  
1/2-14 NPSM  
INTERNAL  
THREADS  
HIGH TEMPERATURES (ABOVE 215° F [102° C])  
DO NOT USE FOR TEMPERATURES ABOVE 266° F [130°C]  
M1942  
Fig. 7. Mounting dimensions of 136733 Heat Block in in. (mm).  
Mounting a C7044A On a Blast Tube (Fig. 9)  
The C7044 is designed to be mounted on the blast tube of a  
burner. The exact location should be determined by the burner  
manufacturer. Contact the manufacturer before making any  
modifications to the installation.  
WARNING  
Can cause serious injury or property damage.  
The C7044 will allow air leakage through its housing.  
Do not locate the C7044 in an atmosphere of fuel  
vapors under positive pressure. The C7027 or C7035  
should be used if internal pressure sealoff is required.  
Explosion Hazard.  
7
60-2026—11  
 
C7027A, C7035, C7044A, C7927A MINIPEEPER® ULTRAVIOLET FLAME DETECTORS  
WIRING (ALL MODELS—FIG. 10)  
CAUTION  
Can cause improper operation.  
8-32 RHIS  
(EUROPEAN M-4)  
SCREW (2)  
Equipment Damage Hazard.  
The blue (tan with blue tracer with C7035A1080)  
leadwire must be connected to the F terminal of the  
flame safeguard control subbase or terminal strip  
and the white (tan leadwire without blue tracer with  
C7035A1080) to the G terminal (see Fig. 10).  
Failure to observe the circuit polarity by reversing  
the leadwires (even momentarily) may cause the  
flame detector to improperly supervise the combustion  
flame.  
IMPORTANT  
MOUNTING  
BRACKET  
All wiring must comply with applicable local electrical  
codes, ordinances and regulations. Use NEC Class  
1 wiring.  
CLAMP  
SCREW  
The detector has color-coded and labeled, plastic-insulated,  
no. 18 AWG leadwires, eight ft. (2.44 m) long, rated for 221°F  
(105°C).  
1. 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.  
C7044A  
DETECTOR  
NOTE: 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.  
29/32 IN. (23.0 mm)  
MOUNTING HOLE  
IN BLAST TUBE  
2. If needed, splice detector leadwires for longer leadwire  
runs, observing the following considerations:  
a. Make required splices in a junction box.  
b. Use moisture-resistant no. 14 wire suitable for at  
least 167°F (75°C).  
1-27/64 IN.  
(36.1 mm)  
M3020  
c. For high temperature installations, use Honeywell  
Specification no. 32004766-003 or equivalent for  
the F leadwire. This wire is rated up to 400°F  
(250°C) for continuous duty. It is tested for operation  
up to 20 Kv and for breakdown up to 35 Kv. For the  
other leadwires, use moisture-resistant no. 14 wire  
selected for a temperature rating above the  
maximum operating temperature.  
d. F and G wires must be run in their own conduit  
independent of other power carrying leadwires.  
More than one scanner F and G wire can be run in  
the same conduit.  
e. A shielded twisted pair wire may be substituted for  
using conduit for routing the F leadwire. Be advised  
of the capacitance per foot of shielded wire  
effectively reduces the flame signal at the flame  
safeguard device. Be sure to ground the shield to  
the G terminal at the flame safeguard wiring  
subbase.  
Fig. 8. Mounting C7044A Detector on blast tube.  
The C7044 is mounted in a 29/32 in. (23.0 mm) hole in the  
blast tube. The mounting bracket is fastened to the blast tube  
with 2 screws on 1-27/64 in. (36.1 mm) centers.  
The mounting bracket is designed so that the detector can be  
removed from the blast tube for cleaning and then replaced  
without disturbing the sighting angle. Loosen the 2 screws  
holding the bracket to the blast tube, but do not loosen the  
clamp screw on the bracket. Twist both the bracket and  
detector to remove them.  
f. The detector wires need to be run in their own  
conduit as well, avoiding other electrical noise  
carrying wiring.  
60-2026—11  
8
 
 
C7027A, C7035, C7044A, C7927A MINIPEEPER® ULTRAVIOLET FLAME DETECTORS  
g. The scanner wires should remain separated a  
minimum of two in. (51 mm) from other line voltage  
wires in the main control panel to the flame  
safeguard device.  
WIRING SUBBASE  
OR  
TERMINAL STRIP  
BLUE  
3. Avoid installation considerations that can influence  
detector operation and maximum leadwire length, such  
as:  
F
UV DETECTOR  
UV DETECTOR  
WHITE  
G
BLUE  
a. Moisture.  
b. Ignition interference.  
WHITE  
c. High resistance connections—poor grounds.  
d. Leadwire capacitance.  
e. Voltage fluctuations.  
OPTIONAL  
SECOND  
DETECTOR  
M3018  
f. Induced line transients.  
g. Floating grounds—ground at some voltage above  
earth ground.  
Fig. 9. Wiring C7027A, C7035A, and  
C7044A flame detectors in parallel.  
h. No G wire—burner used as ground.  
i. Detector output less than maximum attainable for  
the installation (inadequate sighting.  
ADJUSTMENTS AND CHECKOUT  
IMPORTANT:  
Before welding the C7027A, C7927A or C7035A sight pipe  
in its final location, or before tightening the C7044A clamp  
screw, complete both the adjustments and checkout tests that  
follow and any required by the burner manufacturer.  
Do not run the flame detector wiring in the same  
conduit with high voltage ignition transformer wires.  
Connecting Detectors In Parallel  
For a flame that is difficult to sight, using two flame detectors  
connected in parallel will reduce the occurrence of nuisance  
shutdowns. If only one of the parallel detectors loses the flame  
signal, the other will continue to indicate the presence  
of the flame and keep the burner in operation.  
Uv Sensor Tube Test  
NOTE: For initial burner lightoff, consult the burner  
manufacturer instructions or the instructions  
for the flame safeguard control.  
When the flame detectors are connected in parallel, the low  
level background signals are additive. Therefore, no more  
than two C7027A, C7035A, or C7044A Flame Detectors  
should be paralleled. Furthermore, the background signal  
increases as temperature decreases. Because of this, the  
minimum ambient operating temperature must be increased  
when the C7027A, C7035A or C7044A Flame Detectors are  
paralleled.  
During the initial burner lightoff, make sure the flame  
safeguard control starts (i.e., the load relay, usually 1K,  
pulls in). If it does not start, visually check the sensing tube in  
the C7027A, C7035A, or C7044A flame detector. If the tube  
continues to glow when no flame is present, replace the  
sensing tube (C7035A), or replace the detector (C7027A or  
C7044A).  
When using detectors rated for a minimum of 0°F (-18°C),  
limit the minimum ambient temperature at the detectors to  
32°F (0°C). When using detectors rated for a minimum of  
-40°F (-40°C), limit the minimum ambient temperature at the  
detectors to -10°F (-23°C).  
Adjust Detector Sighting Position  
With the flame detector installed and burners running, adjust  
the position of the flame detector for optimum flame signal.  
The flame signal will be read in microamps or voltage (Vdc)  
depending on the Honeywell flame safeguard combustion  
control used.  
Connect the blue leadwires of both detectors to the F terminal  
of the wiring subbase or terminal strip, and the white  
leadwires of both detectors to the G terminal, as shown in  
Fig. 10.  
Most existing Honeywell flame safeguard controls incorporate  
a flame current jack on the flame amplifier or on the control  
itself. The flame signal can be measured with a volt-ohmmeter  
such as the Honeywell W136A. To measure the flame current  
(signal), use a cable connector (part number 196146, included  
with the W136A) in conjunction with the meter. With the  
W136A (or equivalent) positioned at the zero to 25  
microampere scale, make connections from the meter probes  
to the two ends of the cable connector plug (red to red, black  
to black). Make these connections before inserting the plug  
end of the connector plug into the flame jack of the control  
or control amplifier (see Fig. 11). Read the flame signal in  
microamperes directly from the W136A meter. Refer to  
Table 1 for the minimum acceptable flame currents.  
Earth Ground  
The detector and the flame safeguard control must be  
connected to earth ground. A convenient method of  
accomplishing this is to connect the detector to the flame  
safeguard control with a flexible conduit, or ensure a good  
ground connection at the mounting bracket.  
9
60-2026—11  
 
 
C7027A, C7035, C7044A, C7927A MINIPEEPER® ULTRAVIOLET FLAME DETECTORS  
Measure the flame signal voltage as illustrated in Figs. 12  
and 13. Be careful to connect the positive meter lead to the  
positive (+) amplifier jack and the negative meter lead to the  
negative (-) amplifier jack (BCS 7700) or the (-Com) jack for  
a 7800 SERIES control. If the BCS 7700 and Series 7800  
controls have the optional Keyboard Display Module, a zero  
to five Vdc reading will be displayed on the module.  
W136A VOLT-  
OHMMETER  
196146 METER  
CONNECTOR  
PLUG  
W136A SELECTOR  
SWITCH  
PLUG  
Move the flame detector and sight pipe (if not permanently  
attached to the burner/boiler) to view the flame from various  
positions. Allow a few seconds for the meter reading to  
stabilize. A maximum steady microamp or voltage reading is  
desirable. The flame signal must be above the minimum  
acceptable level for the flame safeguard control and  
associated amplifier as indicated in Table 1.  
FLAME SIGNAL  
METER JACK  
PLUG-IN FLAME  
SIGNAL AMPLIFIER  
Measure the flame signal for the pilot alone, the main burner  
flame alone, and both together (unless monitoring pilot only  
when using an intermittent pilot or supervising the main flame  
only when using direct spark ignition). Also, measure the  
flame signal at low and high firing rates and while modulating  
(if applicable).  
RED (+)  
METER  
LEAD  
RED CONNECTOR  
BLACK CONNECTOR  
M6532A  
BLACK (–) METER LEAD  
Fig. 10. Measuring microamp flame signal.  
With the flame detector in its final position, all flame signals  
must be steady with a current/voltage value as indicated in  
Table 1. If the minimum signal cannot be obtained or is  
unstable, refer to Troubleshooting, page 10.  
The R7749B and R7849A,B Amplifiers used with the  
Honeywell BCS 7700 and 7800 SERIES controls,  
respectively, have a dc voltage flame signal output.  
For the R7749B Amplifier, a volt-ohmmeter with a zero to 5 or  
10 Vdc scale and a minimum sensitivity of 20,000 volts/ohm is  
suggested.  
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.  
Follow the procedures in both the Instructions for the  
appropriate flame safeguard control, and in the burner  
manufacturer's instructions.  
For the R7849A,B Amplifiers used with the 7800 SERIES  
controls, a volt-ohmmeter with a zero to 5 or 10 Vdc scale and  
a minimum sensitivity of one megohm/volt is recommended,  
(see Fig. 12).  
PROGRAM  
MODULE  
RESET  
BUTTON  
POSITIVE (+)  
METER LEAD  
ONE  
MEGOHM/VOLT  
METER  
NEGATIVE (-)  
METER LEAD  
20,000  
VOLT-  
OHMMETER  
FLAME  
AMPLIFER  
METER  
PROBES  
M7860  
BCS 7700 CHASSIS MODULE FOOTMOUNT  
M7382  
Fig. 12. Measuring the BCS 7700 flame signal voltage.  
Fig. 11. Measuring flame signal voltage  
of 7800 SERIES controls.  
60-2026—11  
10  
 
Table 1. Flame Signal.  
Honeywell Flame MinimumAcceptable Maximum Current  
Minimum  
Acceptable  
Voltage (Vdc)  
Maximum  
Voltage  
(Vdc)  
Flame  
Detector  
Plug-in  
Amplifier  
Safeguard  
Steady Current  
(microamps)  
Expected  
(microamps)  
Control  
C7027A,  
C7035A,  
C7044A  
R7249A  
BC7000 + PM720 3.5  
7.5  
R7749B  
(AMPLICHECK™)  
BCS7700A  
2.2  
4.98  
a
a
a
R7249A  
3.5  
3.5  
7.5  
7.5  
R4075C ,D ,E  
a
a
R4138C ,D  
R4140G,L,M  
3.5  
1.5  
7.5  
a
R7290A  
None  
2.25  
R4795A,D  
a
1.5  
2.25  
R7023C  
NONE  
R7795A,C,E,G  
7800 SERIES  
1.5  
2.25  
R7849A or  
1.25  
5.0  
R7849B  
(AMPLICHECK™)  
None  
RA890G  
1.5  
2.25  
C7927A  
R7851B  
7800 SERIES  
1.25  
5.0  
a
Currently obsolete.  
Ignition Spark Response Test  
Response to Other Ultraviolet Sources  
Test to be sure that ignition spark is not actuating the flame  
relay (usually 2K) or flame LED in the flame safeguard control.  
Some sources of artificial light produce small amounts of  
ultraviolet radiation. Under certain conditions, an ultraviolet  
detector will respond to them as if it is sensing a flame.  
Do not use an artificial light source to check the response  
of an ultraviolet detector. To check for proper flame detector  
operation, test for flame failure response under all operating  
conditions.  
1. Close the pilot and main burner manual fuel shutoff  
valves.  
2. Connect the appropriate meter to the flame safeguard  
control amplifier. Start the burner and run through  
the ignition period. Ignition spark should occur, but  
the flame relay must not pull in or the flame LED  
should not light. The flame signal should not be more  
than 0.25 microamp or 1.25 Vdc with the BC7700 or  
7800 SERIES.  
3. If the flame relay does pull in or the flame LED lights,  
reposition the flame detector to increase the distance  
between the flame detector and the ignition spark. If the  
flame detector is not in the line of sight of the ignition  
spark but appears to respond to the spark, it may be  
responding to reflected spark generated UV radiation. If  
so, relocate the flame detector so it does not receive the  
reflected UV radiation. It may be necessary to construct  
a barrier to block the UV radiation generated by the  
spark from the flame detector view.  
Weld The Sight Pipe (or Tighten  
the C7044A Clamp Screw)  
When the flame signal is acceptable after all adjustments are  
made, remove the flame 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 flame detector.  
NOTE: If using a C7044A Detector with no sight pipe,  
do not remove the detector; tighten the clamp  
screw securely.  
Final Checkout  
4. Continue making the adjustments until the flame signal  
due to ignition spark is less than 0.25 microamp or  
1.25 Vdc.  
Before putting the burner into service, check out the  
installation using the procedures in the Checkout section of  
the Instructions for the appropriate flame safeguard control.  
After completing the checkout, run the burner through at least  
one complete cycle to verify correct operation.  
5. The use of the Q624 or Q652 solid-state ignition  
transformer may also provide a method to eliminate the  
C7027A, C7035A, or C7044A flame detector response  
to UV radiation generated by ignition spark. The Q624  
and Q652 prevents flame detector response to ignition  
spark by providing alternating periods of spark  
generation and UV sensor activation. If ignition spark is  
detected, try reversing the leads on the Q624 or Q652.  
11  
60-2026—11  
 
C7027A, C7035, C7044A, C7927A MINIPEEPER® ULTRAVIOLET FLAME DETECTORS  
5. Clean the inside of the sight pipe (if one is used) before  
TROUBLESHOOTING  
reinstalling the detector.  
6. If the flame signal continues to be too low, replace the  
plug-in amplifier (if the control has one).  
7. If you still cannot obtain a proper flame signal, replace  
flame detector (C7027A, C7044A) or UV radiation  
sensing tube (C7035A).  
WARNING  
Electrical Shock Hazard.  
Can cause serious injury or death.  
Be extremely careful while troubleshooting the  
detector; line voltage is present on some of the  
terminals when power is on.  
IMPORTANT:  
At the completion of troubleshooting, be sure to  
perform the Adjustments and Checkout beginning  
on page 8.  
Open the master switch to disconnect power before  
removing or installing the detector.  
MAINTENANCE  
Inadequate Flame Signal  
If a satisfactory flame signal cannot be obtained while  
adjusting the sighting position of the detector, perform the  
procedures indicated in steps 1 through 7. If other difficulties  
are encountered in the system, refer to Troubleshooting in the  
Instructions for the appropriate Honeywell flame safeguard  
control.  
Periodic Maintenance  
1. Clean the viewing window and sight pipe (if used) when  
necessary. Remove the detector and use a soft, clean  
cloth to remove accumulated contaminants from the  
UV radiation sensor tube glass envelope.  
2. Ultraviolet sensing tubes have a life expectancy of  
40,000 hours of continuous use within the ambient  
temperature and voltage ratings. Replace the sensing  
tube in the C7035, or replace the C7027, C7927 or  
C7044 Detector, at appropriate intervals.  
3. Keep the flame detection system adjusted for the  
smoothest, most reliable operation as recommended by  
the burner manufacturer.  
1. Check for proper line voltage. Make sure the master  
switch is closed, connections are correct, and power  
supply is the correct voltage and frequency.  
2. Check the detector wiring for defects, including:  
a. incorrect connections.  
b. wiring type or size of wire.  
c. deteriorated wire.  
d. open circuits.  
e. short circuits.  
Cleaning the C7044A Detector  
f. leakage paths caused by moisture, soot, or dirt.  
3. With the burner running, check the temperature at the  
detector. When it exceeds 215°F (102°C) for a C7027,  
C7927 or C7044, or 250°F (121°C) for a C7035:  
a. use a heat block (part no. 136733) if using a  
C7027A Flame Detector.  
When necessary, clean the C7044 Flame Detector by using  
the following procedure:  
1. Loosen the two screws holding the C7044 mounting  
bracket to the blast tube. To remove, twist the bracket  
and detector. Do not loosen the clamp screw that holds  
the mounting bracket to the detector.  
2. Clean the viewing window with a soft, clean cloth.  
3. Insert the detector into the mounting hole, and to realign  
it, twist against the mounting screws. Tighten the two  
mounting screws.  
b. add the additional insulation between the wall of the  
combustion chamber and the detector.  
c. add a shield or screen to reflect radiated heat away  
from the detector, or  
d. add cooling (refer to Sight Pipe Ventilation, page 6).  
4. Remove the detector and clean the viewing window with  
a soft, clean cloth.  
Home and Building Control Home and Building Control  
Honeywell  
Honeywell Limited-Honeywell Limitée  
1985 Douglas Drive North  
Golden Valley, MN 55422  
35 Dynamic Drive  
Scarborough, Ontario  
M1V 4Z9  
Printed in U.S.A. on recycled  
paper containing at least 10%  
post-consumer paper fibers.  
60-2026—11 G.R. Rev. 07-01  
 
   

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