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© STULZ GmbH – all rights reserved EN/04.2021
steam humidifier iNstruCtiONs
11.1 Steam humidifier
The steam humidifier is an optional extra for your A/C unit. It is installed complete and integrated within the
function and method of operation of the A/C unit. Details concerning the connection assignment for the pow
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er supply can be found in the electrical diagrams in the appendix.
Steam generation
Any time steam is requested, the electrodes (2) are supplied with voltage via
main contactor (1). Simultaneously, the inlet valve (7) opens and water enters
the steam cylinder (3) from the bottom via water cup (4) and supply line (5). As
soon as the electrodes come in contact with the water, current begins to flow
between the electrodes, eventually heating and evaporating the water. The
more the electrode surface is exposed to water, the higher is the current con
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sumption and thus the steam capacity.
Upon reaching the requested steam capacity, the inlet valve closes. If the
steam generation decreases below a certain percentage of the required
capacity, due to lowering of the water level (e.g. because of the evaporation
process or drainage), the inlet valve opens until the required capacity is availa
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ble again.
If the required steam capacity is lower than the actual output, the inlet valve
is closed until the desired capacity is achieved by lowering of the water level
(evaporation process).
Level monitoring
A sensor provided in the steam cylinder cover detects when the water level
gets too high. The moment the sensor comes in contact with water, the inlet
valve closes.
Drainage
As a result of the evaporation process, the conductivity of the water increases
due to an escalating mineral concentration. Eventually, an inadmissibly high
current consumption would take place if this concentration process were per
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mitted to continue. To prevent this concentration from reaching a value, unsuit
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ably high for the operation, a certain amount of water is periodically drained
from the cylinder and replaced by fresh water.
During the drainage process, the drain valve (6) is opened. Following a prede
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termined time of drainage, the drain valve is closed again.
Control
With the ECCM/S control unit either On/Off control or proportional control can
be employed for steam production.
Below a minimum controllable steam output, proportional control will work in
two-point operation (on/off control).
11.1.1 Description
The steam humidifier OEM2 is a pressureless steam generator that utilizes an electrode heating and is desi
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gned for air humidification via a steam distributor (steam distribution pipe, steam nozzle).
On/Off control
Proportional control
X = steam capacity in %
Y = Output signal controller
