Xylem Lowara Servitec Degassing Unit OMI User Manual
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General description
’Servitec 30’ is a degassing and make-up station. It can be
used in a wide range of system conditions. The main field
of application is heating and cooling circuits and wherever
air problems in the form of dissolved or free gases cause
problems in systems.
The ’servitec’ vacuum spray-tube degassing system re-
moves up to 90 % of the dissolved gases from the system
water.
Vacuum degassing of a part flow of the circuit water takes
place according to an optimized schedule using selectable
degassing programs.
A part flow of the circuit water is sprayed through the
nozzle (7). The vacuum is created by the pump (6).
The large surface area of the sprayed water and the
intense vacuum result in the extremely high degassing
performance. The degassed water is returned to the
system. There the water is again able to dissolve gases.
The gases separated in the pump (6) are expelled using
the dipstick-tube degassing unit (5). This degassing
interval is repeated and free as well as dissolved gases
are removed from the circuit water.
Degassing interval
The degassing interval is a time-controlled, pre-pro-
grammed process that consists of the degassing time,
expulsion time, and idle time. The time periods can only
be changed in the service menu by Reflex Service.
The degassing intervals are repeated according to the
continuous degassing mode (standard = 5 h a day) or
interval degassing mode (standard = 16 x a day).
Injection time
The pump (6) starts. A vacuum (dependent on temperature) can be read off the displaY after a short time. This is
possible because the pump (6) draws more water from the pump casing than is able to flow in via the pressure supply
port with nozzle (7). Spraying via the nozzle commences as soon as the vacuum begins to be established.
The water level in the pump casing (6) drops continuously while the pump (6) is running. The timing program and pres-
sure setting have been selected so that the pump does not become low in water.
Expulsion time
The pump (6) switches off. The water continues to be sprayed into the pump casing by the system pressure (at least 0.5
bar). The water column in the pump casing rises gradually during the expulsion time.
The vacuum is still maintained during this phase of the interval. At the end of the expulsion phase, the rising water
column compresses the removed gas within a few seconds, expelling it into the atmosphere via the dipstick-tube
degassing unit (5)
Idle time
This is followed by the idle time during which redegassing takes place.
Make-up
In the case of the ’servitec 30’, the pressure in the heating or cooling system is registered and monitored with the help of
the pressure transducer (8). If the fill pressure drops below pF = p0 + 0.2 bar, make-up degassing is activated until
pF = p0 + 0.3 bar has been reached. Time (20 min default setting), cycle (3 in 2 hours) and volume monitoring are active
during this process.
The motorized ball valve (2) opens during make-up. During pump operation, a pressure of approx. - 0.6 bar is set in the
pump casing (pressure indicator display). In the event of a cyclical pump stop, the system pressure is checked and made
up if necessary.
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5
6
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Mode of Operation