Westric DW Series, Installation, Operation And Maintenance Manual

Page: 37 / 48

76-1002-00 Page 37 of 48
Operation Devices
When steam production is required, the electronic control closes the contactor by applying voltage to the
electrodes inmersed in water.
The electrical current flowing through the electrodes is measured with a current transformer.
When steam production drops below the preset value, and this is followed by a drop of water level, the control will
send a signal to the filling electro-valve, which sends water to the charging tray; gravity then causes water to enter
into the cylinder.
The charging tray is equipped with two electrodes for measuring the conductivity of feed water, which is a
reference used by the electronic control to optimize the operation of the humidifier, depending on the chemical
characteristics of feed water.
There are two small high-level electrodes in the upper part of the cylinder. These electrodes control water level so
that it will not exceed the maximum allowed level. Any water above this level will be rained through the drain tube.
The drain electro-valve is actuated by means of the control, with a frequency depending on the characteristics of
feed water, in order to keep the optimal salt concentration inside the cylinder.
The operating principle is the same in all humidifiers. However, humidifiers with more than one cylinder only have a
single control sending a command signal to an interface card, to allow the simultaneous operation of individual
cylinders, regarding the filling electro-valve, drain pump connection.
CAUTION:
Before connecting the water line to the unit, open the tap and let water run for a few minutes to clean
the tube from all impurities that may clog the filling or drain valves, or which may damage the electrodes.
The humidifier is controlled by a system which automatically loads water into a drum, measures water conductivity
and, based on the current flowing through the electrodes, adds or drains water to work with the required electric
current. In case water is not adequate, some lights will flash (see failure box) indicating which the problem is.
This control is also responsible for cleaning the electrodes by circulating water (at this time the humidifier function
is switched off).
Electrodes will deteriorate with use. This will depend on the frequency of use and the type of water used, Working
with good quality water, as explained below, will extend the working life of the electrodes.
For the correct operation of the humidifier, water parameters must be as follow:
From 15 to 40 French degrees 1**
From 125 to 1,250 micro Siemens 2**
Caution must ne exercised with treated water, since calcium and magnesium are replaced with sodium upon water
treatment, which makes water less hard but is not good for the conductivity of the electrodes. Quite on the contrary,
this may cause quick wear-out and even failure of electrodes within a few hours.
We recommend well water or tap water.
Do not use demineralized water.
1** The French degree is used to measure water hardness, it is equivalent to 10 mg/L of calcium carbonate in
water
2** The
siemens (electrical conductance)
, symbol (S), is the unit for measuring electrical conductivity. This unit
is also called
mho
, derived from spelling ohm backwards, because the conductance is the reciprocal of electrical
resistance.