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Safety valve is mounted on the cold water inlet identified with a blue ring. Each hot service water pressure
heater must have a safety valve with a membrane spring. Nominal clearance of safety valves is defined in the
ČSN 0 60830 standard. The safety valve must be well accessible, as near 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. 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 manual moving of the
membrane from the seat, turning the make-and-break device button always in the direction of the arrow.
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 draining valve. First,
close water input into the heater
Find necessary pressure values in the following table - Table 2.
ADMISSIBLE OPERATING
SAFETY VALVE STARTING
MAX PRESSURE IN THE
WATER HEATER PRESSURE
PRESSURE [MPa]
COLD WATER PIPE [MPa]
[MPa]
0.6
0.6
up to 0. 48
Table 2
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.
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