Ignition Interference Test; Hot Refractory Hold-In Test; Ignition Spark Response Test - CleaverBrooks CFC-500 Operation, Service And Parts Manual

NOTE: If the sequence does not stop, reset the system and
make sure that you selected the Pilot Test.
7. Turn down the pilot gas pressure very slowly, reading the
manometer (or pressure gauge) as it drops. Stop
instantly when the FLAME LED goes out. Note the
pressure reading. The pilot flame is at the minimum
turndown position. Immediately turn up the pilot pressure
until the FLAME LED comes on again or the flame signal
increases to above the flame threshold value. (See flame
threshold parameter).
NOTE: If there is no flame for 15 seconds in the TEST posi-
tion, the Falcon module locks out.
8. Repeat step 7 to verify the pilot gas pressure reading at
the exact point the FLAME LED light goes out.
9. Increase the pilot gas pressure immediately until the
FLAME LED comes on, and then turn it down slowly to
obtain a pressure reading just above the dropout point or
until the flame signal increases to above the flame
threshold value (See flame threshold parameter).
10. Turn the pilot hold test OFF and allow the controller to
start a burner cycle. During the Main Flame Establishing
Period, make sure the automatic main fuel valve(s)
opens; then smoothly open the manual main fuel shutoff
valve(s) (or any other manually-opened safety shutoff
valve(s), if used) and watch for main burner ignition. If
the lightoff is not rough and the main burner flame is
established, go to step 18.
NOTE: This step requires two people, one to open the
manual valve(s) and one to watch for ignition.
11. If the main burner flame is not established within 5
seconds, or within the normal lightoff time specified by
the equipment manufacturer, close the manual main fuel
shutoff valve(s) and open the master switch. If the lightoff
is rough, the pilot flame size is too small.
12. Close the master switch and perform another pilot hold
test (see step 5).
13. Increase the pilot flame size by increasing its fuel flow
until a smooth main flame lightoff is accomplished.
14. Reposition the flame rod or the flame scanner sight tube
or use orifices until the pilot flame signal voltage is in the
range of 0.7 Vdc above the flame threshold value.
15. When the main burner lights reliably with the pilot at turn-
down, disconnect the manometer (or pressure gauge)
and turn up the pilot gas flow to that recommended by
the equipment manufacturer.
16. If used, remove the bypass jumpers from the terminals,
limits/controls, or switches.
17. Run the system through another cycle to check for
normal operation.
18. Return the system to normal operation.

IGNITION INTERFERENCE TEST

(FLAME RODS)
Ignition interference can subtract from (decrease) or add to
(increase) the flame signal. If it decreases the flame signal
enough, it causes a safety shutdown. If it increases the flame
signal, it could cause the FLAME LED to come on when the
true flame signal is below the minimum acceptable value.
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 Vdc) indicates ignition interference.
To Eliminate Ignition Interference
1. Make sure there is enough ground area.
2. Be sure the ignition electrode and the flame rod are on
opposite sides of the ground area.
3. Check for correct spacing on the ignition electrode. (See
manufacturer's recommendation.)
4. Make sure the leadwires from the flame rod and ignition
electrode are not too close together.
5. Replace any deteriorated leadwires.
6. If the problem cannot be eliminated, consider changing
the system to an ultraviolet flame detection system.
HOT REFRACTORY HOLD-IN
TEST (ULTRAVIOLET
DETECTORS)
This condition can delay response to flame failure and also can
prevent a system restart if hot refractory is detected.
The ultraviolet detector can respond to hot refractory above
2300 F (1371 C).
1. When the maximum refractory temperature is reached,
close all manual fuel shutoff valves, or open the electrical
circuits of all automatic fuel valves.
2. Visually observe when the burner flame or FLAME LED
goes out. If this takes more than 3 seconds, the detector
is sensing hot refractory.
3. Immediately terminate the firing cycle. Lower the set-
point to the operating controller, or set the Fuel Selector
Switch to OFF. Do not open the master switch.
NOTE: Some burners continue to purge oil lines between the
valves and nozzles even though the fuel valves are
closed. Terminating the firing cycle (instead of open-
ing the master switch) allows purging of the combus-
tion chamber. This reduces buildup of fuel vapors in
the combustion chamber caused by oil line purging.
4. If the detector is sensing hot refractory, correct the condi-
tion by one or more of the following procedures:
a. Add an orifice plate in front of the cell to restrict the
viewing area of the detector.
b. Resight the detector at a cooler, more distant part of
the combustion chamber. Make sure the detector
properly sights the flame.
c. Try lengthening the sight pipe or decreasing the pipe
size (diameter).
For details, refer to the detector Instructions and the equipment
Operating Manual. Continue adjustments until hot refractory
hold-in is eliminated.
IGNITION SPARK RESPONSE
TEST (ULTRAVIOLET
DETECTORS)
Test to make certain that the ignition spark is not actuating the
FLAME LED:
69
CB FALCON
750-265