Drazice 250, Operating And Installation Manual

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The heater’s cold water inlet must be fitted with a T-fitting with a discharge valve for any
discharge of water from the heater
Each individually lockable heater must also be equipped at the hot water inlet with a test
cock, check valve, safety valve and level gauge.
2.3
PLUMBING FIXTURE
Power water connects to pipes with 3/4” thread in the bottom part of the heater. Blue - cold
water supply, red – hot water outlet. For potential disconnection of the heater, the service
water inlets and outlets must be provided with screw coupling Js 3/4”. Safety valve is
mounted on the cold water inlet identified with a blue ring.
Each hot service water pressure heater must have a membrane spring loaded with a safety
valve. Nominal clearance of safety valves is defined in the Standard. The heaters are not
equipped with a safety valve. The safety valve must be easily accessible, as close to the
heater as possible. The input pipes must have at least the same clearance as the safety valve.
The safety valve is placed high enough to secure dripping water drain by gravity. We
recommend mounting the safety valve onto a branch pipe. This allows easier exchange
without having to drain the water from the heater. Safety valves with fixed pressure settings
from the manufacturer are used for the assembly. Starting pressure of a safety valve must be
identical to the maximum allowed heater pressure, and at least 20% higher than the
maximum pressure in the water main (Table 3). If the water main pressure exceeds such
value, a reduction valve must be added to the system. No stop valves can be put between
the heater and the safety valve. During the assembly, follow the guide provided by the safety
equipment manufacturer.
It is necessary to check the safety valve each time before putting it into operation. It is
checked by manually moving of the membrane from the seat, turning the make-and-break
device button always to the right. After being turned, the button must click back into a
notch. Proper function of the make-and-break device results in water draining through the
safety valve outlet pipe. In common operation, such a check needs to be implemented at
least once a month, and after each heater shutdown for more than 5 days. Water may be
dripping off the drain pipe of the safety valve; the pipe must be open into the air, pointed
down; environment temperatures must not drop below zero.
When draining the heater, use a recommended drain valve. First, close water input into the
heater. Find necessary pressure values in the following table. For proper safety valve
operation, a backflow valve must be mounted on the inlet pipes, preventing spontaneous
heater draining and hot water penetrating back into the water main. We recommend that
the hot water distribution from the heater was as short as possible to minimise heat losses.