hajdu HB300C Manuel De Mise En Service, D'opération Et D'entretien page 92

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panel. Before setting the clock and other parameters or programs, please follow the
instructions of chapter 4.
FOR PERSONNEL AUTHORIZED TO PERFORM MAINTENANCE
10. MAINTENANCE INSTRUCTIONS
WARNING!
Please follow the general warnings and safety precautions listed in the
previous chapter and please comply with them strictly.
Any operations and activities has to be performed by qualified personnel (so
they have to possess expertise as required by effective regulations).
WARNING!
Before repair or maintenance, the appliance always must be switched off and
the external switch must be turned into "OFF" position.
10.4. Appliance discharge
Water drainage can be performed through the blow off button (faucet) mounted in front
of the hot water tank or through the combined safety valve, turning the button in the
direction indicated by the arrow, through the water outlet tube. Before water drainage,
the valve closing pipeline connection and the cold water faucet have to be closed, while
the hot water faucet has to be kept opened during water drainage.
ATTENTION! HOT WATER MAY OUTFLOW DURING WATER DRAINAGE!
If you perceive water leaking or any malfunctioning from the interior of the appliance,
switch it off from the water pipeline system immediately with the help of the closing
valve.
10.5. Storing and combined safety valve
In order to ensure safe operation, it is rational to turn to a plumber to check the
appliance and the correct operation of the combined safety valve every now and then
(in every year). Furthermore, it is recommended to blow off the valve every month or
every second month through turning the blow off button of the safety valve in the
direction indicated by the arrow. This way, the valve seat is cleaned from any possible
pollution (sand grains, scale, etc.)
10.6. Active anode
The internal surface of the tank covered by enamel made of steel sheet, which
represents complementary protection against corrosion, is supported by active anode.
The life-cycle of the active anode depends on the quality and temperature of the water.
In case of water of lower temperature, the extent of active anode diminution is less.
IN CASE OF NEGLECTING THE ABOVE INSTRUCTIONS THAT CAUSES
DAMAGE TO SAFETY AND USAGE FEATURES OF THE APPLIANCE, YOU LOSE
YOUR GUARANTEE AND WARRANT RIGHTS.
10.7. Scale removal
Depending on the quality of the water, scale deposition may occur on the heater
exchanger or on the tank. The scale deposited on the heater decreases heating
efficiency. So, it is necessary to clean the hot water tank from scale every second year.
It is strictly forbidden to apply any sharp metal object or acid to remove scale
deposited on the heat exchanger, the close cover and its fittings. Please use cleaning
and scale removal supplies available in commerce.