Atmos
Heating Systems
Installation and user manual EN_FMT
24
6.2.4. Static pressure monitoring
If the water pressure is less than 0.2 bar, the regulation locks
with a ‘P’ + ‘pressure’ on the display.
This lock is removed when the water pressure goes above 1.3
bar.
With a water pressure between 0.5 and 0.2 bar, the burner is
limited to low load.
The display shows alternately the ‘P’ and the normal status
display.
If the water pressure is greater than 3.0 bar, the regulation
locks with a ‘P’ + ‘pressure’ on the display.
This lock is removed when the water pressure goes below 2.9
bar.
6.2.5. Difference in temperature
If the temperature difference between flow and return is
greater than 45°C, the regulation locks. The lock is removed
with a difference of less than 20°C.
If the temperature difference between flow and return is less
than –5°C, the regulation will lock immediately during central
heating and 20 seconds after ignition during tapping.
6.2.6. Maximum temperature limitation
If the flow temperature goes above 105°C, when the burner is
off, the regulation will lock with a continuous ‘H’ (hysteresis
5°C).
If the flow temperature goes above 105°C, when the burner is
on, the regulation will lock with a flashing ‘H’. Only a reset will
remove the interlock.
If the flow or return temperature goes above 97°C, the
regulation will lock.
6.2.7. Flue gas temperature limitation
If, after switching the supply voltage on, a flue gas
temperature of greater than –25°C is measured, the flue gas
sensor is present. If a temperature below –25°C is measured
afterwards, the regulation locks with the message flue gas
sensor interruption (‘4’).
If the flue gas temperature goes above 80°C, the burner is
limited to low load.
If the flue gas temperature goes above 90°C, the regulation
locks with ‘A’.
If the flue gas temperature goes below 70°C, both locks are
removed.
If the flue gas temperature goes above 95°C, the regulation
locks with ‘A’.
6.2.8. Flow sensor protection
The difference between flow and return temperatures must be
less than 20°C before each burner start. The difference
between flow and return temperatures must be raised by 3°C
within 10 seconds after each burner start. However, if the
difference is less than the previous temperature difference,
the burner is started again after 10 seconds.
During this time, the capacity supplied by one of the hot water
Combi-boilers during tapping is the desired capacity and in all
other cases the initial capacity.
If the difference is not detected, the regulation locks with a ‘P’.
This lock is removed when the flow temperature goes below
65°C and the minimum locking time (30 s) has elapsed.
If this lock occurs more than three times within a heat
demand, the regulation locks with ‘1’.
If the difference between flow and return temperatures
becomes less than –5°C during burning, the regulation locks.
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.
6.2.9. Frost protection
When the flow temperature goes below 8°C (if there is no
heat demand), the pump goes over to the central heating
circuit and the display shows ‘o’.
If the flow temperature goes below 3°C, the burner goes to
low load.
When the return temperature goes above 15°C, the frost
protection is finished.
When an external sensor is connected and the outside
temperature goes below –4°C, the pump goes to central
heating. This situation is removed at an outside temperature
of –2 °C.
6.2.10. Monitoring the fan speed
When the measured fan speed deviates from the desired
speed, this is masked in operation for 10 seconds. After these
10 seconds, the burner will go out of operation and the post-
ventilation program will be performed.
When the measured fan speed deviates from the desired
speed during pre- or post-ventilation, the regulation locks. If
this lock lasts for longer than 60 seconds, the regulation locks
with ‘5’.
When the measured fan speed goes above a maximum value
during the rest state, the regulation locks. If this lock lasts for
longer than 60 seconds, the regulation locks with ‘5’.
6.2.11. Glow plug protection
The glow plug protection counter is incremented at each
ignition. This counter is decremented per minute. If this
counter is too high, the burner demand is blocked.
