Azbil 81447514-001, Руководство пользователя

Страница: 47 / 62

39
Chapter 5. Trial Operation and Adjustment
„
Pilot turn-down test
WARNING
Make sure that the pilot turn-down test is done properly.
If the flame detector is able to detect a pilot flame that is too small to ignite the main burner, and if
there is a flame failure of the main burner, this device will not be able to recognize the flame failure.
As a result, fuel will continue to be supplied, resulting in an explosion hazard.
Before doing the pilot turn-down test, always make sure that all manual fuel valves are closed.
If the pilot turn-down test must be repeated, stop the combustion equipment completely each time
and discharge all of the unburned gas and oil from the fuel chamber and flue. Failure to discharge
unburned gas may result in an explosion hazard.
After completing the pilot turn-down test, turn off the power switch to turn off the power supply.
Make sure to return all test jumpers and limit or controller settings to their original values.
Resuming normal operation without returning the settings to their original values, etc., may
damage the equipment or cause a gas leak or explosion.
CAUTION
The pilot turn-down test should be carried out only by an experienced specialist possessing
knowledge and skills pertaining to combustion equipment and combustion safety.
The purpose of this test is to determine the smallest possible pilot flame that will
reliably ignite the main burner.
Before and after this test, make sure to measure the flame voltage and confirm that
it is 2.0 V or more.
(1) Turn off the power to the combustion equipment to stop all devices.
(2) Close the main valve (by removing one side of the wiring to the main valve or
by closing the manual cock) to cut off the gas to the main burner. Open the pilot
valve to its normal position.
(3) Turn on the power switch. If the start input is on, the ignition sequence begins
after the prepurge, as soon as the pilot valve is opened.
(4) After the pilot burner ignites, turn the pilot valve (manual cock) down until the
burner controller extinguishes the flame. Mark the position of the manual cock
at the time when the flame is extinguished. Then, press the reset switch to reset
the error and restart the burner controller. Turn the manual cock back until just
before the previously marked position (so that more gas is output).
(5) Turn off the power switch, return the main valve to the normal state (open the
manual cock) and then turn on the power switch again. After the prepurge, pilot
burner combustion begins, followed by main burner combustion.
If the main burner does not ignite, turn off the power switch immediately.
In this case the pilot flame is too small, so it must be increased. After increasing
the pilot flame, change the position of the flame detector so that its monitoring
angle is slightly away from the pilot flame monitoring axis.
(6) Change the gas pressure from the minimum to the maximum and repeat steps
(1) to (5) to check if the main burner ignites properly.