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Honeywell C7076D Product Data page 17

Adjustable sensitivity ultraviolet flame detectors
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4. After each step in the following procedures, realign the
detector with the faceplate and check for a meter
reading at the Flame Current jack on the detector (Fig.
18).
a. If you get a reading above 1.4 microamperes and
the flame relay (in the flame safeguard control) pulls
in, return to Sensitivity Adjustments.
b. If you do not get a reading, orient the detector away
from the faceplate sufficiently far enough to provide
access to the wiring at the terminal block and
proceed with troubleshooting Procedure A.
c. If you get a reading but the flame relay (in the flame
safeguard control) does not pull in, orient the
detector away from the faceplate sufficiently far
enough to provide access to the wiring at the
terminal block and proceed with troubleshooting
Procedure B.
Troubleshooting Procedures for C7076A and
C7076D Flame Detectors.
NOTE: If the detector develops a signal at the Flame Current
jack, skip troubleshooting Procedure A.
Procedure A: Zero Flame Signal Reading at
Detector; Flame Relay Does not Pull In.
1. Complete the Preliminary Procedures listed above.
2. Refer to the wiring diagram on the inside of the front
cover plate or to Fig 14 or 15 for terminal locations.
3. Check for proper line voltage. Connect an ac voltmeter
across terminals 2 and 1 (or 8, if detector is non-
European 240 volt, 50/60 Hz model) on the terminal
block. Make sure the ac voltage measured is within the
voltage range listed in Table 3, below, for the particular
detector model used.
NOTE: The nominal voltage rating is printed on the trans-
former cover next to the sensitivity controls on the
rear of the plug-in electronics chassis.
a. If there is no voltage, make sure line voltage power
is connected to the master switch, the master switch
is closed and overload protection (circuit breaker,
fuse, or similar device) has not opened the power
circuit.
b. If the measured voltage is not within the proper
voltage range, make sure the main power supply is
of the correct voltage and frequency. Then trace the
wiring between the detector and the main power
supply to determine the problem.
Table 3. Line Voltage Ratings for the Detector.
Nominal Voltage
Rating
Minimum
100
85
117
99.5
120
102
200
170
220
187
240
204
C7076A,D ADJUSTABLE SENSITIVITY ULTRAVIOLET FLAME DETECTORS
Acceptable Line Voltage
Maximum
110
128.7
132
220
242
264
4. Determine if the self-checking shutter is open by looking
into the front of the detector through the pipe in the
wiring compartment.
a. If the shutter is not open, connect an ac voltmeter
across terminals 3 and 4 on the terminal block.
Make sure the ac voltage measured is within the
voltage range listed in Table 4.
NOTE: The nominal voltage rating is printed on the
transformer cover next to the sensitivity controls on
the rear of the plug-in electronics chassis.
Table 4. Shutter Voltage Range.
Nominal Detector
Voltage Range
100
117, 120, 200, 220,
240 or 220/240
(1) If the proper voltage is present, replace the coil
and shutter assembly or the entire plug-in
electronics chassis (see Service section).
(2) If the measured voltage is not within the proper
voltage range, connect a dc voltmeter (capable
of measuring 50 volts) across terminals 6 (F)
and 5 (G) on the terminal block (F is+, G is -)
(a)If the voltage is 2 volts or more, replace the
plug-in electronics chassis )(See Service
section).
(b)If the voltage is less than 2 volts, trace the
shutter wiring between the detector and the
flame safeguard control (refer to Fig 14 or 15).
If the wiring is correct but the proper voltage is
still not present, replace the plug-in R7476A or
R7886 Dynamic Self-Check Ultraviolet
Amplifier.
b. If the shutter is open, make sure the sensitivity
control on the plug-in electronics chassis is not set
too low for the flame conditions encountered. (Refer
to Adjustments and Checkout section.)
5. Make sure the viewing path is clear.
a. Clean the sight pipe. Make sure there are no
obstructions in it.
b. Make sure the proper viewing lens is used.
NOTE: Window glass does not transmit ultraviolet radiation.
You can check for an improper lens by testing the
detector with the lens removed.
c. Clean the viewing lens with a soft, clean cloth.
6. If the previous actions have not corrected the problem,
replace the 191053 Ultraviolet Sensing Tube (See
Service section).
7. If you still do not get a meter reading, replace the plug-in
electronics chassis.
Procedure B: Flame Signal Reading Present at
Detector; Flame Relay Does Not Pull In)
1. Complete the Preliminary Procedures listed above.
2. Determine if the self-checking shutter is closed by look-
ing into the front of the detector through the pipe in the
wiring compartment.
17
Acceptable Shutter Voltage
Minimum
Maximum
85
110
99.5
132
95-8269—1

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