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C7076A,D ADJUSTABLE SENSITIVITY ULTRAVIOLET FLAME DETECTORS
6. Secure the swivel mount (if used), or tack weld the sight
pipe. Do not weld the sight pipe permanently into place
until you have accomplished the spark hold-in and pilot
turndown tests.
7. Remove the plug from the Flame Current meter jack.
8. Replace the rear cover plate and tighten the four screws
securely.
Multiburner System Using C7076A Detector (Flame
Discrimination)
1. Complete steps 1 through 8 under Single Burner
System above for each burner.
2. With all A sensitivity controls set to MAX position and all
burners firing at full load, select one burner and proceed
as follows:
a. Shut down the chosen burner, then note the flame
signal reading.
b. Loosen the locking nut on Sensitivity Control A.
c. Gradually reduce the sensitivity by turning Control A
counterclockwise until the flame relay (in the flame
safeguard control) drops out.
Fig. 17. Set up for Sensitivity Controls A and B adjustments, C7076A Detector.
Multifuel System
For multifuel systems, use one sensitivity control for each fuel.
Follow steps 2 and 3 above for each fuel.
95-8269—1
SELECTOR
SWITCH
W136A TEST METER
(SET AT SPL)
RED (+)
METER LEAD
BLACK (–)
METER LEAD
d. Relight the burner and note the flame signal
reading. The difference between the new reading
and the initial reading in step a represents the
degree of flame discrimination.
e. Repeat the run-shutdown-dropout procedures
(steps 2a-d) until the optimum setting has been
achieved.
f.
Hand tighten the locking nut on Sensitivity Control
A, then tighten another 1/4 turn, but do not
overtighten.
NOTE: If the sensitivity control on a detector is reduced to
MIN position and flame discrimination cannot be
achieved, insert an orifice plate in the sight pipe. An
orifice of the proper diameter will reduce the
ultraviolet radiation reaching the detector so that the
sensitivity can be adjusted to effect flame
discrimination.
3. Repeat step 2 for Sensitivity Control A on each burner.
4. Repeat step 2 for Sensitivity Control B (if used) on each
burner. Verify that Sensitivity Controls A and B on each
detector are properly indexed by the system fuel
selector, firing rate switch, etc.
SENSITIVITY
ADJUSTMENT
LOCKING NUT
PLUG
117053
METER
CONNECTOR
PLUG
RED
SPADE TIP
BLACK
SPADE TIP
14
SENSITIVITY
C7076A
CONTROL
FLAME
DETECTOR
PLUG-IN
ELECTRONICS
CHASSIS
(REAR VIEW)
M20762
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