Klingenburg CERTO, Documentation, Page: 40 / 52

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Operation instructions controller
Switching contact for alternating between inlet and outlet air humidifier mode
The CERTO controller can use a potential-free contact (control terminals 5 and 6) to alternate between operating
two humidifiers with different settings. In the menu, set the 2 sets of parameters (P1 and P0) for the maximum
frequency and the control range extension, one for an inlet air humidifier and one for an outlet air humidifier.
If the switching contact at control terminals 5 and 6 is open, then parameter set P1 is active and the
3/2 way valve (valve output 38) is not triggered.
If the other humidifier is to be activated, switch control terminals 5 and 6 to potential-free before start-up. This
will switch on parameter set P0 and the 3/2 way valve is switched over via the valve output (38).
If the switching contact is opened again while the machine is shut down, the other humidifier will be active again.
When operated for half a year, the switching contact must be open or closed during the entire run time.
7. Fault and error messages
Controller disabled
When this message appears in the display, the control unit is
externally disabled via terminals 11 and 12. That is to say, the
DDC has not enabled the control unit or the connection is faulty e.g. due to loose terminals etc. Generally, the
message “Controller disabled” is not a fault, the controller has merely not been enabled because, for example,
the fan was switched off.
Line pressure
Message appears when the line pressure drops below 1.6 bar.
When this message appears on the display, the primary pressure (flow pressure) of the feedwater pipe has drop-
ped below 1.6 bar. The pressure switch sends an enabling signal to the control unit when the pressure reaches 2
bar. If the pressure drops below the minimum limit for a maximum of 30 seconds, the message “Line pressure?”
is displayed.
If the pressure rises above 2 bar again during this time, the humidifier starts automatically. If the pressure drops
below the minimum limit for more than 30 seconds, a fault message is displayed. This fault can be caused by
several factors. The water supply may be switched off or restricted. The water supply pressure drops below 2 bar.
The water filter is heavily contaminated. The supply pressure can also drop due to increased flow rate.
C o n t r . b l o c k e d !
R I s t f r e q . : 0 0 H z
W a t e r p r e s s u r e ?
R I s t f r e q . : 0 0 H z