t=7sec t<12sec
5.1. Standby
Fan off - Gas valve on - Glow plug off - Ionisation off
During the standby, a check is made to see if there is
burner demand. If so the boiler will go over to pre rise.
If the glow plug counter is too high (the boiler made too
many starts repeatedly) the regulation blocks the burner
demand.
Once per hour, if there is no heat demand, the difference
between flow and return temperatures must be less than ±
5°C. If this is not the case, the pump will be switched on
and a check will be made for a maximum of 10 minutes to
see whether the temperature difference goes to within ±
5°C.
If a false flame signal is detected during standby for more
than 5 seconds, the regulation runs into lock-out, flashing
indication ‘8’:
5.2. Pre purge
Fan on - Gas valve on - Glow plug on - Ionisation off
The pre-purge time is defined as the time that it takes for
the fan to be in the range of the setpoint value for a fixed
amount of time. The ramp-up of the fan speed is not part
of the pre-purge time.
The difference between flow and return temperatures
must be less than 20°C before each burner start.
Fan: The fan is switched on at purging speed (1800 rpm).
After a few seconds, the fan goes from purging speed to
the faster ignition speed (2900 rpm).
When the measured fan speed deviates from the desired
speed the regulation blocks. When this situation lasts for
more than 60 seconds, the regulation runs into lock-out,
flashing indication ‘5’.
Gas valve: The gas valve is still closed during pre-purge
time
Glow plug: The glow plug is switched on for the last part of
the pre-purge time.
Pump: The pump is running, controlled by the heat
demand of the firmware.
5.3. Ignition
Fan on - Gas valve on - Glow plug on/off - Ionisation
off/on
Fan: The fan is running at the ignition speed (2900 rpm).
Gas valve: The gas valve is on and allows gas to flow.
Glow plug: The glow plug is on, till an ionisation signal is
measured. If there is no ionisation at the end of the safety
time, a new attempt at ignition will be made if this was not
the last permitted (third) attempt at starting. The safety-
time is defined as the time that the gas valve is allowed to
be opened without the flame necessarily being present.
5.4. In operation
Fan on - Gas valve on - Glow plug off - Ionisation on
To ensure the water flow through the heat exchanger a 20
second temperature test is activated. After each burner
start the flow temperature must rise 3°C more than the
return temperature within the first 20 seconds.
If the temperature rise is less than 3°C, the burner is
started again after 10 seconds. If this occurs more than
three times within a heat demand, the regulation runs into
lock-out, flashing indication ‘1’.
If the return temperature becomes 5°C above the flow
temperature, the regulation blocks. The burner remains
blocked until the temperature difference becomes correct.
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