ECOSAIRE EN Series, Owner'S Manual

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OEM
CAREL code +030221791 - rel. 2.1 – 21/09/07 30
7. OPERATING PRINCIPLE, CONTROL AND OTHER FUNCTIONS
7.1 Operating principle
In an electrode humidifier the production of humidity is obtained inside a cylinder (boiler) containing water that is heated to and then held
at boiling temperature. The water that evaporates over time is automatically replaced with water from the mains supply.
The heat
required to boil the water is produced by passing an electrical current through the cylinder. This is done by connecting the
electrodes immersed inside the cylinder to the mains power supply.
The quantity of current that initially flows depends greatly on the type of water supplied from the mains. Normally, a recently-started
cylinder has low current; nonetheless, over time the quantity of salts inside the water increases (evaporation in fact does not carry the salts
with it). This allows the level of current required by the unit to provide the quantity of steam requested to be reached.
In stable operating conditions, the level of production required is automatically achieved using the water level control on the cylinder.
This is in fact reflected in higher or lower levels of current.
The salts introduced by the automatic refilling of the water are partly deposited as lime scale inside the cylinder, contributing to the
progressive depletion of the cylinder, and partly remain dissolved in the water. To avoid excessive accumulation of salts, a quantity of
water is periodically and automatically drained and then replaced with fresh water.
7.2 Control principles
The range of humidifiers includes the following control options.
7.2.1 ON/OFF control - CP controllers
The action is all or nothing, activated by an external contact that consequently determines the control set point and differential.
7.2.2 Proportional control - CP controllers
The steam production (quantity per hour) is proportional to the value
of a signal Y coming from an external device; the type of signal can
be selected – programmed via RS485 – from the following standards:
0 to 10 V (default), 2 to 10 V, 0 to 1 V. The entire range is indicated
as BP (proportional band).
The maximum production, Pmax, corresponding to the maximum
value of the Y external signal, and can be programmed between 20%
and 100% of the rated humidifier value (dip A3-A4).
The minimum production, Pmin, is set to 20% of the rated value, with
an activation hysteresis, given by the value hy, corresponding to 2%
of the entire BP interval of the external signal Y.
PRODUZIONE
DI VAPORE
hy
OFF ON
Pmax
P
min
hy
Y
BP
Fig. 6.2.2.1