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4 Operating Description
4 Operating Description
(For example chart, see chapter 10.7 Process Sequence Charts)
Should the burner be switched on, a "Burner On" signal would first be sent to terminal 58. The
burner control unit would send a request to the safety interlock chain (SIC) and the air pres-
sure monitor contact. If it does not recognise any "good condition", a corresponding message
would be displayed and the operating control would be stopped.
Should all signals be appropriate, the fan output would be activated and the channels run to
testings of the lower range limits.
When all channels have reached the lower limit range, purging starts. The valve leakage test
runs parallelly (only in gas operation).
With the actuators, the purging is used to read and test the range limits. After the upper range
limits are achieved, the fuel actuator would run to ignition position. All other channels remain
in OPEN position. A request is sent to the air pressure monitor. If this signal is o.k., the preset
purging time runs. If the recirculation delay time is achieved, the purging time stops. As soon
as the recirculation channel reaches the purging position, the purging time continues. After
this time, the channels run in the programmed ignition position (recirculation closed).
4.1 Starting without Pilot Burner
The main valves open and together with the ignition transformer remain activated for the du-
ration of the safety time. During this time the flame signal appears.
4.2 Starting with Pilot Burner
The ignition valve and main gas 1 (in gas operation) or the ignition valve alone (in oil operation)
run open. The pilot flame forms and the flame detection detects the flame. The flame detection
sends the signal to the burner control device.
On expiry of the 1
st
safety time, the ignition transformer switches off. For 3 sec. (stabilisation
time) the pilot burner burns alone. Then main gas 2 or the oil valve opens and remains acti-
vated in parallel with the ignition valve for the duration of the 2
nd
safety time. The ignition valve
closes again at the end of this period.
3 seconds after ignition, all channels run to the programmed base firing rate point. The ETA-
MATIC OEM remains in base firing rate position until control release is given.
After control release the ETAMATIC OEM follows the power control unit’s default setting.
A shut off follows the cancelling of the signal of the terminal 58. The main valves close. In gas
operation, first main gas 1 and second main gas 2 closes with a delay of approx. 5 sec., in
order to allow the test line between the solenoid valves to burn out. In the event of a fault shut-
down, both close immediately.
If configured for post-purge, the air channels open again for this period.
Thereafter the ETAMATIC OEM is in the "OFF" mode.
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