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Troubleshooting
Troubleshooting
7.
If a fault occurs the boiler will be shut down immediately. There is a differentiation between blocking and
locking. Blocking means that the boiler can restart itself when there is no more failure. After repairing locking
fault it is necessary to press the Reset-key to confirm, so the boiler can start again.
The failure will be shown on the display of the boiler. The failure code shows if it is a blocking or a locking,
and the type of the failure specified more detailed.
P xx Blocking -> constant indication of the failure code
E xx Locking -> blinking indication of the failure code
If there is a blocking or a locking the main / boiler pump is running permanently (HT-Mode).
Blocking:
P 17 Return > (Flow + 10K) for 30 Sec
If the return temperature is at least 5K higher than the flow temperature for at least 10 seconds it causes a
locking.
P 18 Flow temperature is too high
If the flow temperature is higher than 95°C (defined flow temperature limit), a blocking is caused. There is a
hysterises of 5K.
P 19 Return temperature is too high
If the return temperature is higher than 95°C (defined return temperature limit), a blocking is caused. There
is a hysterises of 5K.
P 25 Increasing of flow temperature is too high
If the defined gradient limiting curve (parameter 15 (2BE)) is exceeded, a blocking is caused. Before the
blocking occurs, the speed is minimised. There is also a limiting curve existing (parameter 16 (2BF).
P 26 Gas pressure is too low/ gas pressure key is broken/ external blocking
(p.e.: emergency-stop deflector)
Occurs, when the burner is demanded and the gas pressure is too low as well as there is an external block-
ing.
P 27 Water pressure is too low
If the water pressure is too low this will be signalised by the gas pressure switch. The boiler weill be block-
ed.
P 28 Blocking entry is open
If the blocking entry is opened the boiler occurs a blocking.
P 29 Flow rate control
When the flue gas temperature is higher as the flow temperature (more than 40°C) so a blocking of the
boiler occurs. A hysteresis of 10K needs to be extended before the blocking „Flow rate control“ is cancelled.
This control is both valid for heating and hot water operation.
P 30 Temperature difference flow - return too large
As soon as the difference between flow and return temperature is higher than the value of the parameter
59 plus 15K, a blocking occurs. The range between the value of parameter 59 und 5K before the shut-down
point will be modulated to the minimum speed linear. See drawing 6.
P 52 Flue gas temperature blocking
If the limiting temperature (parameter 58 (2GC) is exceeded, a blocking occurs. See drawing 5. Instead of
the flue gas temperature the boiler body is observed.
