Water Pressure Safety Relief Valve- Series 374A
OPERATION
As thermal expansion conditions develop, pressure builds up to the setting of the relief valve. this will cause discharging of small quantity of water.
Should operating controls fail, permitting runaway firing, the boiler water may reach steam temperatures. the valve will then open to discharge steam at the rate or faster than the boiler can generate it, thus restoring system pressure to a safer level.
Important: the discharge line must be the same size as the valve outlet, and must pitch downward from the valve to a safe place for disposal. Valve lever must be tripped at least once a year to insure that waterways are clear. this device is designed for emergency safety relief and shall not be used as an operating control.
- Seat located above drain; water can’t be trapped and sediment can’t foul seat.
- Non-mechanical seat-to-disc alignment will not stick or freeze.
- Water seal of high temperature resisting material isolates spring working parts from water during relief.
An ASME Section IV certified pressure relief valve shall be installed on each boiler as noted. The valve shall have a BTU rating in excess of the BTU rating of the boilers heating output. Each hot water space heating boiler shall be equipped with a pressure relief valve set to relieve below the maximum boiler working pressure. The valve shall feature a raised seat and non-mechanical disc alignment. Working parts and spring shall be isolated from any discharge by a high temperature resistant material. Valve shall be a Watts 374A Series.
- Iron body construction
- Bronze inlet
- Nonmetallic disc-to-metal seating
Pressure range: rated up to 550,000 BTU/hr at a 30 psi (2 bars) setting only.
Maximum Temperature: 250°F (121°C).
ASME
| Size(DN) | Height | Length | Weight | ||||
|---|---|---|---|---|---|---|---|
| in. | mm | in. | mm | in. | mm | lbs. | kg |
| ¾ x ¾ | 20 x 20mm | 3 5/8 | 92 | 2 ½ | 64 | 1.13 | .5 |