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1. General information
EJK maxi heaters are designed for heating water in open and closed
metal tanks, including enamelled domestic hot water tanks. In those tanks, in
which anti-corrosion cathodic protection system is using magnesium anode or
external current anode, heating elements should be partially insulated
electrically from tank walls. Thanks to this, the electrochemical potential
difference between heating elements made of copper or special stainless steel
and the tank made of carbon steel is partially equalized in a tank filled with
water. This way the durability of heating elements and the life of the
magnesium anode are increased significantly.
In the EJK heaters with metal head isolation of heating element was
achieved by mounting it in a housing made entirely of plastic. The heater is
placed in a metal head. A grounding resistor of a suitable resistance is used
for a partial connection of heating elements with the tank. The resistor
incorporates these elements in the tank anti-corrosion cathodic protection
system. This is an optimum solution to protect the electric heater inside the
enamelled tank from an accelerated electrochemical corrosion, maintaining
the tank cathodic protection and the magnesium anode life.
2. Structure and technical data
EJK type heaters are built of tubular heating elements with an internal
resistance wire, bezel elements isolating a heater, metal heads and casing
containing a three phase 400V power unit which includes a temperature
controller with stepless temperature adjustment and a non-automatic
temperature limiter to protect the heater from overheating. The temperature
controller knob and signal lamps are situated in the cover closing the upper
part of the casing body. The lower part of casing body ends with a metal head
that has a hexagonal socket for an S-60 wrench and a 1½” thread to screw the
heater to the tank connection. If the hexagonal wrench socket is not
accessible, the heater can be screwed in similarly to a car oil filter for
example, that is, by holding it by the casing which is made of a durable, heat-
resistant plastic. Heaters structure scheme and their technical data are shown
in fig. 1 and in table 1.
