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Manual ENA 7-30
9
8
ENG
3.2. Controller SCU
NO. Description
1
Control panel for the controller, graphical
display, LED for error display, selector switch
(click and roll)
2
Power switch, ON: flashes red
3
Internal fuse F1: T 16 A 250 V
4
Internal fuse F2: T 3,5 A 250 V
5
Hardware release, service menu E2
6
Terminal bars for
• Electric supply;
• Sensors;
• Impulse water counter;
• External activation for refilling process;
• Collective malfunction message;
• Pump.
7
Interface RS485.
1
2
3
4
5
6
7
3.3. Working principle
The automat serves primarily as an active deaerating device. In addition as a make-up device for
re-filling the water
losses in a system.
3.3.1. Deaeration
For deaerating the water, the system water is drawn
in via a bypass from the return line of the system
(H). The water is run through a flow regulator (G)
and the strainer (F) into the deaeration tank (C). It is
subjected to a vacuum during the cyclic running of
the pump (D) and passed through a Pall-ring (E). As a
result of the lowered pressure, and the large surface
of the Pall-ring, air dissoleves from the water.
When the pump switches off, the replenishing medium flowing into the tank causes the pressure in
the tank to increase to the level of the system pressure so that the air which has accumulated above
the water level is discharged via the vent. device (A). While the pump is running, the water quantity
supplied into the tank is returned via a bypass line to the return branch (B) of the system.
P
P
H
F
G
C
A
B
E
D
Fast deaeration mode (Fast = Turbo):
An interval during which the pump is running (vacuum is
forming) alternates with an interval during which the air
is discharged (pump is stopped).
Normal deaeration mode:
An additional pause is added between the end of the
evacuation interval and the starting of the pump. This
additional interval can be selected via a parameter within
fixed limits. Upon expiry of the deaeration interval, the
system changes to the normal deaeration mode, which
then takes place continuously. The normal deaeration
mode is interrupted by a selectable pause (by default
06.00 p.m. - 08.00 a.m.). The beginning of the next
deaeration cycle taking place in the normal deaeration
mode is indicated via a countdown in the Process menu.
3.3.2. Make-up operation
The make-up water is supplied in a pressure-controlled or level-controlled mode. The automat is set
by default to pressure-controlled refilling (if a diaphragm expansion vessel is used).
Pressure-controlled supply:
The system is equipped with a pressure sensor (P) for
sensing the pressure. The make-up activating pressure
should be Po* + 0.2 bar. The make-up deactivating
pressure must be at least 0.1 bar higher than the make-
up activating pressure. The make-up water flow rate or
feed time can be monitored, if the system is fitted with
a litres counter. The pump (D) must be automatically
stopped cyclically during pressure-controlled refilling,
and the actual system pressure must be checked and, if
necessary, additional water must be supplied until the
make-up deactivating pressure is reached.
Level-controlled supply:
In this case, make-up water is supplied as long as the
external make-up request is active and the flow-rate and
time monitoring feature of the automat allows making up
to take place.
It is possible to deactivate the make-up function. Refer to chapter 6.1.
* Po = P P Steam
