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AHU Resistors Humidifier - REH
Inside the hydraulic units are arranged longitudinally the heaters (special stainless steel resistor with protec-
tion) connected to the electrical power supply phases and easily removable.
On top cover are present longitudinal slits that allow the output of the produced steam. Due to the positioning
of the unit inside the AHU, the steam can mix with air flow along the unit section.
This solution prevents the formation of condensate in the piping and also prevents any increase of the steam
pressure in the boiler due to obstructions in the steam conveying tubes.
On one side of the kettle (the easiest to access once installed) you have:
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Level switch
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Drain block
5 Working Principle
When switched on, the humidifier performs a complete drain of kettle, thus ensuring to operate with clean
water. If the humidistat requires steam production, the humidifier starts to fill with water until it reaches the
level of exercise. If the time required to reach that level is greater than a predetermined value, the humidifier
stops and indicates an alarm (possible causes are lack of power or breaking of level switch). Upon reaching the
water level, the control unit switches the control system of the heater elements (resistors).
The resistors are connected to three contactors so as to allow the production to be proportional to the request.
The control unit will maintain production at the set value with additions or discharges of water.
The maximum temperature of the boiler is controlled by NTC sensors (max value set at 125°C) with humidifier
stop and signalling in case of alarm. Each heater element has an intrinsic supplementary safety system consti-
tuted by a thermistor fuse that opens when the resistor temperature exceeds 150°C.
At regular intervals, the humidifier makes also small purges, so as to ensure that the salt content in the water
is not too high and thus avoiding an excessive deposit of limestone.
At much longer intervals (default value 4h) the control system will make complete draining of the boiler to
remove limestone deposits.
If the humidistat request is zero for a long period, the control unit provides to empty all the water contained
in the kettle so as to avoid health problems due to rotting in the water tank.
6 Characteristics
Elsteam S.r.l - via E. Fermi, 496 - 21042 Caronno Pertusella (va) - Tel.+39 02 9659890 - Fax +39 02 96457007
21.2.EN
Figura 2 – heaters elements inside kettle
The drain block has been specially designed to empty the tank from water
and limestone pieces without having to block and having to be able to work
without pressure.
It is essentially constituted by a valve having a free passage of 32 mm in
diameter, closed by a damper operated by an electric motor and a cam.
Grafted rigidly on the pivot motor is an electronics rotation sensor, which,
communicating with the microprocessor control is able to manage the cor-
rect operation of the system and communicate any faults that appear in the
display.
E-mail: info@elsteam.it Web: http://www.elsteam.com
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