C7005A,B
Gas Pilot and Flame Rod Assemblies
PRODUCT DATA
FEATURES
• Used with Honeywell controls using the flame
rectification principle.
• C7005A is for continuous pilot applications. It includes
an insulated flame rod, properly positioned relative to
the flame retention type nozzle.
• C7005B is similar to C7005A, but includes an ignition
electrode suitable for automatic, electric-spark
ignition, gas pilot applications.
• Individually mounted flame rod and ignition electrode
in ceramic insulators allow the head assembly to fit
inside a 3-inch pipe.
• Stainless steel fins on the flame retention type pilot
head provide the correct ratio of flame rod area to
ground area for maximum flame signal, and are
beneficial in stabilizing the pilot flame.
GENERAL
The C7005A,B Gas Pilot Burner Assemblies include a flame
rod to prove the pilot flame. The assemblies are used with a
suitable flame safeguard control on industrial or commercial
gas burners or oil burners with gas pilots.
• Pilot flame retention nozzle and mixing tube are
threaded internally, 1/2-14 NPT and 3/8-18 NPT,
respectively, and can be assembled with standard pipe
fittings.
• Pilot can be installed in vertical, horizontal, or inclined
position.
• Rajah connectors facilitate electrical connections.
Contents
General ............................................................................... 1
Features .............................................................................. 1
Specifications ...................................................................... 2
Ordering Information ........................................................... 2
Installation ........................................................................... 3
Adjustments and Checkout ................................................. 5
Operation ............................................................................ 8
Copyright © 1995 Honeywell Inc. • All Rights Reserved
60-2033-3
C7005A,B GAS PILOT AND FLAME ROD ASSEMBLIES
SPECIFICA TIONS
IMPORTANT
The specifications given in this publication do not
include normal manufacturing tolerances. Therefore,
this unit may not exactly match the listed
specifications. Also, this product is tested and
calibrated under closely controlled conditions, and
some differences in performance can be expected if
those conditions are changed.
Models:
C7005A Gas Pilot and Flame Rod Assembly—for
continuous pilot applications; includes flame rod only.
C7005B Gas Pilot and Flame Rod Assembly—for
automatic pilot applications; includes flame rod and
ignition electrode.
Pilot Head:
Flame retention type with stainless steel bomb type fins.
Threaded onto 1/2 x 6 inch (152 mm) pipe nipple with
1/2-14 NPT external threads.
Type of Gas:
Models available for use with natural and propane gases.
Gas Capacity (Varies with Gas Pressure):
Gas Pressure
in. wc
3 0.75 12.0 0.34
4 0.99 13.7 0.39
5 1.24 15.3 0.43
6 1.49 16.8 0.48
7 1.74 18.2 0.52
Flame Rod/Ignition Electrode Insulators:
Ceramic.
Maximum Temperature at Flame Rod Insulator:
500°F (260°C).
Capacity
kPa ft
3
/hr m3/hr
Flame Rod/Ignition Electrode Material:
Kanthal A-1 (2462°F [1350°C] maximum operating
temperature rating).
Optional: Stainless steel (2000°F [1093°C] maximum
operating temperature rating).
Electrical Connectors:
Rajah, male; companion connectors included.
Insulator Brackets:
Adjustable to change location of flame rod or ignition
electrode; lock securely using setscrew.
Mixing T ube:
Inspirating (Venturi type) with primary air adjustment.
Approximately 4-9/16 inches (116 mm) long, 1-3/4 inches
(44.5 mm) diameter. Inlet tapping 1/4-18 NPT; outlet tapping
3/8-18 NPT.
Mounting:
Vertical, horizontal, or inclined.
Dimensions:
Overall—Height 13-1/2 inches (343 mm); width can be
adjusted to pass through a 3-inch pipe.
Pilot Head—Length 4-7/16 inches (113 mm), diameter
1-5/8 inches (41.3 mm).
Spark Gap (C7005B only—1/8 to 3/16 inch (3.2 to
4.8 mm).
Approvals:
Underwriters Laboratories Inc. Listed: File No. MP268.
Canadian Standards Association Certified: C7005 only—
Master file LR-95329—1.
Industrial Risk Insurers acceptable.
Accessories;
• High Temperature Cable (for operation above 125°F
[52°C])—specify length:
— R1298020 Flame Rod Leadwire, rated up to 400°F
(204°C) for continuous duty.
— R1061012 Ignition Leadwire, rated at 350°F (176°C) for
continuous duty.
— R1239001 High Tension Ignition Leadwire, for
installations in a contaminating environment, rated at
200°F (93°C) for continuous duty.
ORDERING INFORMATION
When purchasing replacement and modernization products from your Authorized Flame Safeguard Distributor, refer to the
TRADELINE® Catalog or price sheets for complete ordering number.
1. Order number.
2. High temperature cable, if required (specify length).
3. Ignition transformer, if required (C7005B only).
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 Home and Building Control Sales Office (check white pages of your phone directory).
2. Home and Building Control Customer Logistics
Honeywell Inc., 1885 Douglas Drive North
Minneapolis, Minnesota 55422-4386 (612) 951-1000
In Canada—Honeywell Limited/Honeywell Limitee, 740 Ellesmere Road, Scarborough, Ontario M1P 2V9 International Sales
and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France, Germany, Japan,
Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A.
60-2033—3
2
C7005A,B GAS PILOT AND FLAME ROD ASSEMBLIES
• Ignition Transformer, 6000 volts secondary (C7005B only):
— Part no. 22042; 120V, 60 Hz primary.
— Part no. 101079; 240V, 60 Hz primary.
Replacement Parts:
100204B Mixing Tube (Venturi type used with natural gas).
101867B Mixing Tube (Venturi type used with LP gas).
100205B Grounding Assembly
101738A Ignition Assembly—includes electrode, Rajah
connector and bracket (C7005B).
101738B Flame Rod Assembly.
101739 Ignition Electrode, 4 inch (102 mm), stainless
steel (C7005B).
101740 Flame Rod, 8 inch (203 mm) stainless steel.
103534 Flame Rod, 8 inch (203 mm) Kanthal.
101741 Connector—Rajah, plug end, 7/8 inch long.
101742 Clamp—for flame rod or ignition electrode mounting.
101743 Bracket—mounting.
14182 Washer—brass (plain), between Rajah connector
and flame rod or ignition electrode mounting.
37356 Connector—Rajah, socket end straight.
7617CV Insulator Assembly—includes electrode insulator
and mounting hardware.
INSTALLATION
CAUTION
1. Installer must be a trained, experienced, flame
safeguard control service technician.
2. Turn off the gas supply before beginning
installation.
3. Disconnect power supply to the flame safeguard
control before beginning installation to prevent
electrical shock and equipment damage. There
may be more than one disconnect involved.
4. All wiring must comply with applicable local
electrical codes, ordinances, and regulations.
5. All wiring must be NEC Class 1 (line voltage).
6. Perform all required checkout tests after
installation is complete.
Mounting
If special provisions for mounting the pilot were made by the
burner manufacturer, carefully follow those instructions. If the
manufacturer did not supply instructions, use the
recommendations below.
Fig. 1 illustrates the use of a 90 degree reducing elbow (not
furnished) to provide a right-angle connection. Use a straight
reducing coupling or a 45 degree reducing elbow (not
furnished) for piping and mounting if more convenient.
Position the flame rod so that a weak pilot flame contacts the
flame rod only at the junction of the main burner flame and
pilot flame.
weak pilot flame that is incapable of igniting the main burner
(Fig. 2).
IMPORTANT
Do not position the flame rod so it can detect a
To assure an adequate pilot flame to ignite the main
burner, you MUST perform the pilot turndown test,
as described in the instructions for the flame
safeguard control.
Install the pilot so the pilot flame has full contact with the gas
stream from the main burner heads, jets or nozzles (Fig. 3,
4, 5). If it is necessary to prove both pilot and main flames,
mount the pilot so the flame travels in the same direction as
the air movement at the mounting point, rather than where
the air movement is at right angles to the flame travel. The
pilot should be mounted far enough forward so that the flame
rod just enters the envelope of the main burner flame. The
pilot can be mounted either beside or below the burner head.
Keep the pilot burner below or behind the main burner so that
the burner frame and refractory help protect the pilot from
radiant heat. Locating the pilot in the secondary airstream
also provides considerable cooling. The primary air
adjustment must be accessible and outside the high
temperature area.
On radiant type burners, the pilot is often mounted outside
the burner box. Fig. 3 shows the pilot assembly in a diagonal
channel cut through the brickwork and a straight-through
connection used to support the pilot. The flame rod is at the
junction of the main burner flame and pilot flame. The pilot
assembly can be mounted below or alongside the burner box
and an angle connection used so the pilot flame travels into
the main flame. The air mixer is normally mounted outside the
boiler.
FLAME ROD
FLAME GROUND
IGNITION ELECTRODE
(C7005B ONLY)
SPARK GAP
FLAME RETENTION NOZZLE
1/2 X 6 INCH (152.4 mm)
PIPE NIPPLE (1/2 -14 NPT
EXTERNAL THREADS)
RAJAH CONNECTORS
1/2-14 NPT X 3/8-18 NPT
ELBOW (NOT FURNISHED)
3/8-18 NPT PIPE
NIPPLE (NOT FURNISHED)
MIXING TUBE
(3/8-18 NPT X 1/4-18 NPT
INTERNAL THREADS)
PRIMARY AIR
ADJUSTMENT
1
1
4-9/16 (115)
1/4-18 NPT
PIPE (NOT FURNISHED
SPARK GAP BETWEEN IGNITION ELECTRODE AND GROUND MUST BE
1/8 TO 3/16 INCH (3.2 TO 4.8 mm).
)
1-1/2
(31)
3/8-18 NPT
13-1/2
(342)
9-3/4
(247)
1/2-14 NPT
M3035A
Fig. 1. C7005 gas pilot and flame rod
assembly in in. (mm).
3
60-2033—3
C7005A,B GAS PILOT AND FLAME ROD ASSEMBLIES
THE FLAME ROD SHOULD BE LOCATED
NOTE:
ON EITHER SIDE OR BELOW THE PILOT.
WRONG
Fig. 2. Improper position of flame rod.
M3038
M3036
Fig. 4. T ypical mounting of gas pilot and flame rod
assembly on multiple head gas burner.
MAIN BURNER
M3037
Fig. 3. T ypical mounting of gas pilot and flame rod
assembly on radiant inshot type burner.
On multiple head installations (Fig. 4), the pilot is usually
centrally located. The pilot can usually be mounted vertically
between burner heads with the pilot flame traveling upward
across the junction of the gas stream from the burner heads.
If the pilot is mounted horizontally on a level with the burner
heads or the flat arch, the pilot flame should travel across the
junction of the gas streams coming from at least two heads.
If a group of inspirating (Venturi type) burners are mounted
within a burner box, sufficient spacing is usually available so
the pilot can be mounted as illustrated in Fig. 5 to
simultaneously light as many burners as possible. If available
space does not allow central mounting within the burner box,
see Fig. 3.
60-2033—3
C7005 GAS PILOT AND
FLAME ROD ASSEMBLY
PRIMARY
IGNITION
TRANSFORMER
FURNACE
Fig. 5. T ypical mounting of gas pilot and flame rod
assembly on inspirating (Venture type) gas burner.
Wiring
CAUTION
1. Turn off gas supply before starting installation.
2. Disconnect power supply before beginning
installation to prevent electrical shock and
equipment damage. There may be more than one
disconnect involved.
4
M3039
All wiring must comply with applicable electrical codes,
FLAME
ROD
IGNITION
ELECTRODE
(C7005B ONLY)
PILOT
HEAD
BURNER
GROUND
CASE
GROUND
6000 VOLT
IGNITION
TRANSFORMER
SECONDARY
PRIMARY
F
L2
HIGH TENSION
TERMINAL
FLAME
SAFEGUARD
CONTROL
M3034
ordinances, and regulations. Use NEC Class 1 (Line
Voltage) wiring.
For normal installations:
For the ignition electrode,
•
use high tension wire
electrically equivalent to type GTO-10, and rated
for the temperature and humidity encountered in
the application.
For the flame rod,
•
use moisture-resistant no. 14
AWG wire suitable for at least 167°F (75°C) if
used with a flame safeguard primary control, or
suitable for at least 194°F (90°C) if used with a
flame safeguard programming control.
For high temperature installations:
For the ignition electrode,
•
use Honeywell
specification no. R1061012 Ignition Cable or
equivalent. (This wire is rated at 350°F (176°C)
for continuous duty, and up to 500°F (260°C) for
intermittent use. It has been breakdown tested to
15,000 volts.)
For the flame rod,
•
use Honeywell specification
no. R1298020 or equivalent. 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 ignition installations in a contaminating environment,
Honeywell specification no. R1239001 High Tension Ignition
Cable or equivalent. This wire is very resistant to severe
conditions of oil, heat, and corona, and is tested to withstand
high voltages up to 25,000 Vrms in a salt bath for one minute
without breakdown. It is rated at 200°F (93°C) for continuous
duty, and up to 350°F (176°C)for intermittent use.
Make connections to the flame rod and ignition electrode
(C7005B) using Rajah connectors. See Fig. 6 for typical field
wiring connections.
Connect the flame rod (see callout 1, Fig. 1) to the F terminal
of the flame safeguard control. Keep this leadwire as short as
possible; capacitance increases with leadwire length,
reducing the flame signal strength.
is the flame signal
(see Table 1).
The ultimate limiting factor
For a C7005B:
• Use a 6000 volt ignition transformer with the
same electrical ratings as the power supply of the
flame safeguard control. Select the appropriate
Honeywell transformer, or its equivalent.
— For 120V, 60 Hz, use part no. 22042.
— For 240V, 60 Hz, use part no. 101079.
• Connect the primary leadwires of the ignition
transformer between the ignition and the L2
terminals of the flame safeguard control.
• Connect the ignition electrode of the C7005B
(callout 3, Fig. 1) to the secondary high tension
terminal of the ignition transformer.
use
C7005A,B GAS PILOT AND FLAME ROD ASSEMBLIES
Fig. 6. T ypical field wiring diagram for C7005
gas pilot and flame rod assembly .
IMPORT ANT
Do not run high voltage ignition transformer wires in
the same conduit with the flame rod wiring.
No ground leadwires are required. The flame ground and
flame retention nozzle (callouts 2 and 4, Fig. 1) act as the
ground electrode for the flame rod and the ignition electrode.
The case of the ignition transformer will act as the ground
connection when it is securely fastened to the burner.
ADJUSTMENTS AND CHECKOUT
Adjust the Air-Gas Mixture
IMPORT ANT
For initial burner lightoff, consult the burner
manufacturer’s instructions or the instructions for the
flame safeguard control.
With the gas pilot installed and the pilot burner running, adjust
the primary air adjustment (callout 10, Fig. 1) for an air-gas
mixture that provides the type of flame required for the
particular installation. Be sure you have the proper mixing
tube for the type of gas (natural or LP) being used. A
medium-hard flame generates the greatest response from the
flame detector circuit.
If air movement conditions are severe or change with
modulation, it may be desirable to operate the premixed pilot
on moderate to high gas pressure (normally not more than
one psi). This is particularly true when the main burner fires
with high pressure gas. Increasing the pilot pressure tends to
harden and lengthen the pilot flame, increasing its stability
under adverse draft conditions.
5
60-2033—3
C7005A,B GAS PILOT AND FLAME ROD ASSEMBLIES
Adjust Flame Rod Position
The pilot flame must make good contact with the flame rod
and furnish reliable ignition for the main burner. Check to be
sure that the flame rod is located at the junction of the main
burner flame and the pilot flame. Ensure that the main valve
opens or unlocks only when the pilot flame is strong enough
to ignite the main burner.
Secondary air velocity over the pilot nozzle must not cause
unstable flame contact with the flame rod, because this
produces chattering of the flame detector relay.
Measure the Flame Signal
With the pilot and main burner(s) operating, adjust the position
of the flame rod for optimum flame signal (current or voltage).
Most existing Honeywell flame safeguard controls incorporate
a flame signal jack located on the control amplifier or on the
control itself. These controls require a Honeywell W136A Test
Meter (see Fig. 7) or its equivalent for measuring the flame
signal in microamperes. The flame signal (current) is
measured by the following procedure:
A Use a Honeywell W136A Test Meter. (If a W136A is not
available, a microammeter with a 0 to 25 microamp dc
range can be used.)
W136A TEST
METER
SELECTOR
SWITCH
196146 METER
CONNECTOR
PLUG
D Insert the plug into the flame signal meter jack and
allow a few seconds for the meter reading to stabilize.
E When using a RA890H,J self-checking flame safeguard
control, press the test button on the control to stabilize
the current reading while making the measurement.
The green flame indicating lamp should be on
continuously while reading the flame signal.
stable
F Read the average
current. For an R7247B
self-check rectification amplifier (AMPLI-CHECK™),
disregard the peaks due to self-checking operation. The
red flame-indicating lamp on an R7247B should blink
about 2-1/2 to 4 times a second (from bright to dim). If
the lamp is on or off continuously while reading the
flame signal, replace the amplifier.
POSITIVE (+)
NEGATIVE (-)
METER LEAD
METER LEAD
ONE
MEGOHM/VOLT
METER
PLUG
FLAME SIGNAL
METER JACK
PLUG-IN FLAME
RED (+)
METER
LEAD
SIGNAL AMPLIFIER
RED CONNECTOR
BLACK CONNECTORBLACK (–) METER LEAD
M6532
Fig. 7. Measuring microamp flame signal.
B Set the selector switch on the test meter to 25 uA for all
standard amplifiers and flame safeguard controls, or to
SPL for an R7247B AMPLI-CHECK™ self-check
rectification amplifier. (If the test meter is not a W136A,
shunt the 0 to 25 microamp dc range with a 50
microfarad capacitor.)
C Use a 196146 Meter Connector Plug (ordered
separately). Connect the red spade tip to the red (+)
meter lead and the black spade tip to the black (–)
meter lead.
M7382
Fig. 8. Measuring flame signal voltage
of 7800 SERIES control.
G The meter reading must be as specified in Table 1 after
all tests are completed and all adjustments are made.
With the Honeywell 7800 Series controls, the flame signal is
measured in Vdc. The voltage flame signal measurement
requires a volt-ohmmeter with a minimum sensitivity of one
megohm/volt and a 0 to 5 or10 Vdc scale. To make the flame
signal measurement on 7800 SERIES controls, use the
following procedure:
A Set the meter to the appropriate scale.
B Insert the positive (red) meter probe into the positive (+)
jack of the 7800 SERIES control amplifier and the
negative (black) probe into the negative (-Com) jack of
the amplifier (see Fig. 8).
C Allow a few seconds for the meter reading to stabilize.
D When using an AMPLI-CHECK™ amplifier, read the
average stable voltage and disregard the peaks due to
the self-check operation.
E The flame signal voltage must be at least the minimum
acceptable voltage as indicated in Table 1.
F If the 7800 SERIES control has the optional Keyboard
Display Module, the flame signal will be displayed on
the module.
60-2033—3
6
C7005A,B GAS PILOT AND FLAME ROD ASSEMBLIES
Table 1. Flame Signal For C7005A,B.
Minimum
Flame
Signal
Amplifier
R7247A BC7000L; R4140G,L,M; R4138C,D; 2.0 5.0
R4075C,D,E
R7247B
AMPLI-
CHECK™
R7257A R4150 2.0 5.0
R7289A R4795 2.0 5.0
R7847A RM7800E,G,L,M; RM7838A,B;
R7847B
AMPLI-
CHECK™
a
Set W136A selector switch to SPL (damped) position to read current.
b
Press test button while reading current.
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 (or
stable) and as specified in Table 1.
a
BC7000L; R4140G,L,M; R4138C,D;
R4075C,D,E
RM7840E,G,L,M; RM7885A;
RM7890A,B; RM7895A,B,C,D
RM7800E,G,L,M; RM7838A,B;
RM7840E,G,L,M; RM7885A;
RM7890A,B; RM7895A,B,C,D
None RA890F, R7795B,D,F,H; R7023B,
R485
None R4181
Flame Safeguard
Control
b
Acceptable
Steady Current
(uA)
1.25 2.50
2.0 5.0
8.0 15.0
Pilot Turndown Test
If the flame rod is used to prove a pilot flame before the main
fuel valve can be opened, perform a Pilot Turndown Test.
Follow the Instruction procedures for the appropriate flame
safeguard control, and the burner manufacturer’s instructions.
Ignition Interference Test
Maximum
Expected
Current
(uA)
Minimum
Acceptable
Steady voltage
(Vdc)
1.25 5.0
1.25 5.0
Maximum
Expected
Steady voltage
(Vdc)
If the signal is unstable or less than the minimum acceptable
current, check the flame rod installation and circuitry:
• Check the supply voltage at terminals L1-L2 on the wiring
subbase or terminal strip for the flame safeguard control.
• Check the wiring for defects including:
— wrong type or size of wire.
— deteriorated wire.
— open circuits.
— short circuits.
— leakage paths caused by moisture, soot, or
accumulated dirt.
• Make sure:
— there is enough ground area.
— the flame rod is properly located in the flame.
— temperature at the flame rod insulator is no greater
than 500°F (260°C).
— ignition interference is not present (see Ignition
Interference Test below).
• Make sure that the flame adjustment is not too lean.
• If necessary, reposition the flame rod.
If you cannot obtain proper operation, replace the plug-in
amplifier if applicable. If you still cannot obtain proper
operation, replace the flame rod.
C7005B
Test to make certain that a false signal from the spark ignition
system is not superimposed on the flame signal.
Ignition interference can subtract from (decrease) or add to
(increase) the flame signal. If it decreases the flame signal
enough, it causes safety shutdown. (The flame relay will not
pull in and the flame safeguard control will act as though the
pilot or main burner, if using direct spark ignition, has not
been ignited.) If it increases the flame signal, it could cause
the flame relay to pull in when the true flame signal is below
the minimum acceptable value.
Test
Start the burner and measure the flame signal with both
ignition and pilot or main burner on, and then with only the
pilot or main burner on. Any significant difference greater than
0.5 microamp, or 0.25 Vdc with 7800 SERIES controls,
indicates ignition interference.
To Eliminate Ignition Interference
A Make sure there is enough ground area.
B Be sure the ignition electrode and the flame rod are on
opposite sides of the ground area (Fig. 1).
7
60-2033—3
C7005A,B GAS PILOT AND FLAME ROD ASSEMBLIES
C Check for correct spacing between the ignition
electrode and ground for 6000 volt systems—1/8 to
3/16 inch (3.2 to 4.8 mm).
D Make sure the leadwires from the flame rod and ignition
electrode are not too close together.
E Replace any deteriorated leadwires.
F If the problem cannot be eliminated, consider changing
to an ultraviolet flame detection system with a
Q624A1014 solid-state spark generator.
Final Checkout
Before putting the burner into service, check out the
installation by following 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 operation.
OPERATION
The C7005B Gas Pilot and Flame Rod Assembly includes an
ignition electrode and a flame rod. The operation of these two
electrodes in a simple electrically-operated, gas pilot
installation is as follows.
At the beginning of the starting cycle, a high voltage from the
secondary winding of the ignition transformer is applied to the
ignition electrode. A spark jumps across the outlet of the pilot
burner. The pilot gas valve is either automatically or manually
opened, and the spark ignites the gas.
When the ignition transformer is energized, ac voltage is
applied to the flame rod through a flame safeguard control.
When the pilot flame appears, this ac voltage is changed to
dc voltage through a rectifying action. This dc voltage then
operates a relay, opening the valve to the main burner (or
permitting it to be manually opened). In the event of flame
failure, flame rectification stops, the gas valves are deenergized, the valves close, and the system shuts down.
Home and Building Control
Honeywell Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
60-2033—3
60-2033—3 Rev. 11-95 J.A. Printed in U.S.A.
Home and Building Control
Honeywell Limited-Honeywell Limitée
740 Ellesmere Road
Scarborough, Ontario
M1P 2V9
Helping You Control Your World
QUALITY IS KEY
8
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