A.O. Smith DURA-Power DRE-52, Инструкция по установке и эксплуатации

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2.2.4 Temperature Regulation
The device is continuously under
water pipe pressure (maximum 8 bar
(=800 kPa)). Cold water may be fed
if hot water is being consumed. The
regulating thermostat switches the feed
automatically. That means that if the
thermostat measures a temperature
lower than the set temperature, then it
closes the electrical circuit so that an
electrical current is conducted through
the heating element. As soon as the
desired temperature is reached the
thermostat breaks the contact once
again. When there are high water
temperatures, scaling in the device
occurs. Therefore it is recommended
to allow the temperature setting to stay
at 60°C so that less scale is formed.
A maximum thermostat is installed
above each regulating thermostat
which shuts off the current feed to the
element permanently (locking) at a
water temperature of 93°C. In order to
put the element back into operation the
reset button of the maximum thermostat
must be pressed in. If the temperature
climbs above 98°C the temperature and
pressure valve fitted open for safety
reasons.
2.3 Maintenance
The boiler must be tested and cleaned
by a recognised installation engineer
at least once per year so that good
operation can be guaranteed. During
maintenance the device must never be
under voltage.
2.3.1 Sacrificial anode
The life of the anodes is determined
by the quality and the quantity of water
flowing through the device. It is thus
recommended that the anodes are
checked every year.
1. Close the stop valve in the cold
water feed pipe.
2. Open up the nearest hot-water tap
so that the water pressure in the
boiler and pipeline drops.
3. Loosen the anode using a correct
spanner.
4. Check the anode and replace if this
is tarnished above 60%.
5. Replace the anode in a water-tight
way.
If it is necessary to replace the anode,
it must be replaced with one of the
same type. The type of anode can be
established via the device type and the
complete serial number.
2.3.2 Descaling
Scaling depends on the water condition
and the water demand. Besides, more
scale deposit will be formed in the device
at high temperatures than at lower
temperatures. A temperature setting of 60
ºC is recommended to ensure low scale
deposit. Descale using the appropriate
agents. A descaling instruction is available
for detailed information.
2.4 Steps When There is a
Fault
Warning:
Always ensure that the device is
completely free of voltage before the
door is opened!