Water Pressure Safety Relief Valve- Series 740
¾" to 2" (20 - 50mm)
Iron body with expanded outlets for hot water space heating boilers. Pressure range 30 to 75 psi (2 to 5 bars) with corresponding high ratings from 925,000 to 10,700,000 BTU/hr.
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.
FEATURES
SPECIFICATIONS
MATERIALS
STANDARDS
ASME
Tested and rated by A.S.M.E. National Board of Boiler and Pressure Vessel Inspectors.
Meets Military Spec. MIL-V-18634B, Type I, Class 3A, Style B (Iron Body).
CAPACITY
PRESSURE-TEMPERATURE
DIMENSIONS - WEIGHT
- 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 740 Series.
- Iron body construction
- Nonmetallic disc-to-metal seating
ASMETested and rated by A.S.M.E. National Board of Boiler and Pressure Vessel Inspectors.
Meets Military Spec. MIL-V-18634B, Type I, Class 3A, Style B (Iron Body).
BTU/hr Steam Pressure Discharge Capacities
As tested and rated by the National Board of Boiler and Pressure Vessel Inspectors
| Set Pressure | ¾^" x 1" 20 x 25mm Model M1 |
1" x 1 ¼" 25 x 32mm Model M |
1 ¼" x 1 ½" 32 x 40mm Model M1 |
1 ½" x 2" 40 x 50mm Model M |
2" x 2 ½" 50 x 65mm Model M |
|
|---|---|---|---|---|---|---|
| psi | bars | |||||
| 30 | 2.07 | 925,000 | 1,300,000 | 2,105,000 | 2,900,000 | 5,525,000 |
| 33 | 2.27 | 989,000 | 1,390,000 | 2,250,000 | 3,125,000 | 5,600,000 |
| 35 | 2.41 | 1,032,000 | 1,450,000 | 2,345,000 | 3,235,000 | 5,850,000 |
| 36 | 2.48 | 1,053,000 | 1,500,000 | 2,395,000 | 3,325,000 | 5,975,000 |
| 40 | 2.76 | 1,139,000 | 1,600,000 | 2,590,000 | 3,569,000 | 6,440,000 |
| 45 | 3.10 | 1,245,000 | 1,750,000 | 2,830,000 | 3,903,000 | 7,067,000 |
| 50 | 3.45 | 1,352,000 | 1,899,000 | 3,075,000 | 4,237,000 | 7,672,000 |
| 55 | 3.79 | 1,459,000 | 2,049,000 | 3,315,000 | 4,572,000 | 8,300,000 |
| 60 | 4.13 | 1,566,000 | 2,200,000 | 3,560,000 | 4,907,000 | 8,875,000 |
| 65 | 4.58 | 1,672,000 | 2,375,000 | 3,800,000 | 5,241,000 | 9,500,000 |
| 70 | 4.82 | 1,779,000 | 2,525,000 | 4,045,000 | 5,575,000 | 10,100,000 |
| 75 | 5.17 | 1,886,000 | 2,649,000 | 4,285,000 | 5,909,000 | 10,700,000 |
Pressure range: 30 PSI to 75 psi (2 to 5 bars) with corresponding high ratings from 925,000 to 10,700,000 BTU/hr.
Maximum Temperature: 250°F (121°C).
| Size(DN) | Model | Height | Length | Weight | ||||
|---|---|---|---|---|---|---|---|---|
| in. | mm | in. | mm | in. | mm | lbs. | kg | |
| ¾ x 1 | 20 x 25mm | M1 | 5 5/8 | 143 | 3 | 76 | 1.88 | .9 |
| 1 x 1 ¼ | 25 x 32mm | M | 7 ¼ | 184 | 3 ½ | 89 | 3.13 | 1.4 |
| 1 ¼ x 1 ½ | 32 x 40mm | M | 8 ¾ | 222 | 4 5/8 | 117 | 6.13 | 2.8 |
| 1 ½ x 2 | 40 x 50mm | M | 9 ¼ | 235 | 5 ¼ | 133 | 7.50 | 3.4 |
| 2 x 2 ½ | 50 x 65mm | M | 11 5/8 | 295 | 6 ¾ | 171 | 16.50 | 7.5 |