Series 174A, 374, 740 - Watts

1 For Pressure Protection of Hot Water Heating BoilersSizes: 3 4" 2" (20 - 50mm) Series 174 ABronze body safety relief valves for pressure protection only of all types of hot water heating boiler equipment. Pressure range 30 to 150psi ( - 10 bar) with corresponding high rat-ings from 650,000 to 14,370,000 BTU/hr. Female inlet and outlet connections. Sizes 3 4" - 2" (20 - 50mm). Series 374 AIron body with forged brass inlet, 550,000 BTU/hr rating. 3 4" (20mm) 740 Iron body with expanded outlets for hot water space heating boilers. Pressure range 30 to 75psi (2 to 5 bar) with corre-sponding high ratings from 925,000 to 10,700,000 Seat located above drain; water can t be trapped and sediment can t foul seat.

2 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.*SpecificationsBoiler Relief ValvesAn 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 boiler s 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.

3 * Valve shall be a Watts Series 174A, 374A or 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. NOTICEThe discharge line must be the same size as the valve outlet, and must pitch downward from the valve to a safe place for lever must be tripped at least once a year to ensure that waterways are clear. This device is designed for emergency safety relief and shall not be used as an operating Hot Water Boiler ApplicationsES-174A-740 Series 174 ASeries 740 Series 174A, 374, 740 ASME Water Pressure Relief ValvesJob Name Contractor Job Location Approval Engineer Contractor s No.

4 Approval Representative Watts product specifications in customary units and metric are approximate and are provided for reference only. For precise measurements, please contact Watts Technical Service. Watts reserves the right to change or modify product design, construction, specifications, or materials with-out prior notice and without incurring any obligation to make such changes and modifications on Watts products previously or subsequently is illegal to use this product in any plumbing system providing water for human consumption, such as drinking or dishwashing, in the United States.

5 Before installing standard material product, consult your local water authority, building and plumbing !The information contained herein is not intended to replace the full product installation and safety information available or the experience of a trained product installer. You are required to thoroughly read all installation instructions and product safety information before begin-ning the installation of this product.* Does not apply to 374 ANOTICEM aterialsSeries 174A Bronze body construction Nonmetallic disc-to-metal seatingSeries 740 Iron body construction Nonmetallic disc-to-metal seatingPressure TemperatureSeries 174 APressure range: 30psi to 150psi (2 to 10 bar) with correspond-ing high BTU/hr ratings from 650,000 to 14,370,000 BTU/hr.

6 Maximum Temperature: 250 F (121 C) Series . 374 APressure range: rated up to 550,000 BTU/hr at a 30psi (2 bar) setting. (Other settings available) Series 740 Pressure range: 30psi to 75psi (2 to 5 bar) with corre-sponding high ratings from 925,000 to 10,700,000 BTU/hr. Maximum Temperature: 250 F (121 C)StandardsTested and rated by the National Board of Boiler and Pressure Vessel Inspectors to the requirements of ASME. Meets Military Spec. MIL-V-18634B, Type I, Class 3A, Style A (Bronze Body), Style B (Iron Body).ASMED imensions WeightsCapacity*BTU/hr Steam Pressure Discharge CapacitiesAs tested and rated by the National Board of Boiler and Pressure Vessel InspectorsSERIES 174 ASize (Dn)

7 4 x 3 420 x 20 31 29021 4 x 3 420 x 20M341 211623 x 125 x 25M153 4 x 11 432 x 32M181 221341 2 x 11 240 x 40M91 423243 x 250 x 50M111 229061 7407403 4 x 120 x 25M155 x 11 425 x 32M71 418431 4 x 11 232 x 40M83 422245 2 x 240 x 50M91 423551 x 21 250 x 65M115 829563 174 ASet Pressure3 4 x 3 4 1 x 1 11 4 x 11 4 11 2 x 11 2 2 x 2 20 x 20mm25 x 25mm32 x 32mm40 x 40mm50 x 50mmpsibarModel M3 Model M1 Model M1 Model M Model ,0001,005,0001,682,0002,020,0003,815, ,0001,075,0001,788,0002,150,0004,080, ,0001,125,0001,877,0002,250,0004,250, ,0001,145,0001,916,0002,310,0004,344, ,0001,240,0002,071,0002,490,0004,690, ,0001,355,0002,265,0002,720,0005,130, ,0001,470,0002,459,0002,950,0005,575, ,025,0001,590,0002,653,0003,190,0006,010 , ,100,0001,702,0002,847,0003,425,0006,450 , ,170,0001,820,0003,041,0003,660,0006,890 , ,245,0001,935,0003,325,0003,890,0007,330 , ,320,0002,055,0003,429,0004,125,0007,770 , ,400,0002,166,0003,605,0004,360,0008,215 , ,470,0002,285,0003,817,0004,590,0008,650 , ,545,0002,400,0004,011,0004,825,0009,090 , ,620,0002,520,0004,205,0005,060,0009,530 , ,695,0002,635,0004,399,0005,290,0009,970 , ,770,0002,750,0004,593,0005,525,00010,41 0, ,845,0002,865,0004,787,0005,760,00010,85 0, ,920,0002,980,0004,981,0005,990,00011,29 0, ,995,0003,100,0005,175,0006,225,00011,73 0, ,070,0003,215,0005,370,0006,460,00012,17 0, ,145,0003,330,0005,564,0006,690,00012,61 0, ,220.

8 0003,445,0005,758,0006,925,00013,050, ,295,0003,565,0005,952,0007,160,00013,49 0, ,370,0003,680,0006,146,0007,390,00013,39 0, ,445,0003,795,0006,340,0007,630,00014,37 0,000 Series 740 Set Pressure3 4 x 1 1 x 11 4 11 4 x 11 2 11 2 x 2 2 x 21 2 20 x 25mm25 x 32mm32 x 40mm40 x 50mm50 x 65mmpsibarModel M1 Model MModel MModel M Model ,0001,300,0002,105,0002,900,0005,250, ,0001,390,0002,250,0003,100,0005,613, ,032,0001,450,0002,345,0003,235,0005,855 , ,053,0001,480,0002,395,0003,300,0005,975 , ,139,0001,600,0002,590,0003,569,0006,461 , ,245,0001,750,0002,830,0003,903,0007,067 , ,352,0001,899,0003,075,0004,237,0007,672 , ,459,0002,049,0003,315,0004,572,0008,277 , ,566,0002,200,0003,560,0004,907,0008,883 , ,672,0002,349,0003,800,0005,241,0009,488 , ,779,0002,499,0004,045,0005,575,00010,09 3, ,886,0002,649,0004,285,0005,909,00010,70 0,000ES-174A-740 1552 2015 WattsUSA: Tel: (978) 689-6066 Fax: (978) 975-8350 : Tel: (905) 332-4090 Fax: (905) 332-7068 America: Tel: (52) 81-1001-8600 Fax: (52) 81-8000-7091 Watts Water Technologies Company