system. No stop valves can be put between the heater and the safety valve. During
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 the recommended drain valve. First, close the water supply 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.
Required pressures – Table 4. We recommend that the hot water distribution from the heater was as short
as possible to minimise heat losses.
SAFETY VALVE STARTING
PRESSURE (MPa)
0,6
0,7
1
Table 4
Heaters must be provided with a discharge valve mounted on the cold service water inlet to the heater
for potential disassembly or repair.
ACCEPTABLE OPERATING OVER-PRESSURE
OF THE WATER HEATER (MPa)
0,6
0,7
1
Figure 1
MAX COLD WATER
PRESSURE IN PIPING (MPa)
up to 0.48
up to 0.56
up to 0.8
O - Air outlet valve
U – Shut-off valve
P1 - Safety valve with backflow flap
P2 - Safety valve for heating circuit
M - Manometer
Z – Test valve
V - Drain valve
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