Product Overview

70
McDonnell & Miller
• For tanks and hydronic heating systems
• Protects against over-pressure
• Minimizes hammering with flash steam
• Low differential pressure – 3 psi (.21 kg/cm
2
) between
opening and closing
• Meets ASME Pressure Vessel and Boiler Code,
Section IV
• Sizes and material
–
3
⁄
4
" - 1" NPT – bronze body and seat
– 2" NPT – cast iron body, brass seat
• EPDM rubber diaphragm and seat disc
• Maximum temperature 250°F (121°C)
• Maximum operating pressure range
30 - 125 psig (2.1 - 8.8 kg/cm
2
)
Series 250
3/4" - 1" (20-25mm) NPT
Series 250
2" (50mm) NPT
Va l v e s
Series 250
Pressure Relief Valves
Size A B C D E F
NPT
3
⁄
4
2
9
⁄
1 6
( 6 5 ) 1
1
⁄
2
(38)
3
⁄
4
(20) 4
9
⁄
16
(116) 1
1
⁄
32
(26) 2
3
⁄
32
(53.2)
1 2
7
⁄
8
( 7 3 ) 1
3
⁄
4
(45)
7
⁄
8
(22) 4
15
⁄
16
(125) 1
1
⁄
32
(26) 2
1
⁄
4
(57)
2 6 (152) 2
7
⁄
8
(73) 3
1
⁄
4
(83) 11 (279) — —
Dimensions, in. (mm)
• For water tanks and hydronic heating systems
• Protects against over-pressure
• Minimizes hammering with flash steam
• Low differential pressure – 3 psi (.21 kg/cm
2
) between
opening and closing
• Meets ASME Pressure Vessel and Boiler Code,
Section IV
• Sealed spring chamber prevents scale or sediment
build-up around seal
• 1
1
⁄
2
" NPT Inlet and 2" NPT Discharge
• Cast iron body, brass seat
• Maximum temperature 250°F (121°C)
• Maximum operating pressure range
30 - 50 psig (2.1 - 3.5 kg/cm
2
)
Series 260
Series 260
Pressure Relief Valves
Size
NPT NPT
Inlet Outlet A B C D
1
1
⁄
2
2 6 (152) 2
7
⁄
8
(73) 3
1
⁄
4
(83) 11 (279)
Dimensions, in. (mm)
Boiler Controls
08. Water Feeders 70-76• 3/6/07 1:48 PM Page 70