
For Commercial and Institutional Applications
ES-77F-DI-250
Job Name  
Job Location 
Engineer  
Approval  
LEAD FREE
 –––––––––––––––––––––––––––––––––––––––––––
 –––––––––––––––––––––––––––––––––––––––––
 –––––––––––––––––––––––––––––––––––––––––––––
 –––––––––––––––––––––––––––––––––––––––––––––
*
Series 77F-DI-250
Flanged, Wye Pattern, Ductile Iron 
Strainers
Sizes: 2" – 12" (50 – 300mm)
Series 77F-DI-250 Flanged, Wye Pattern, Ductile Iron Strainers 
feature a one-piece cast body, bolted cover flange with flat gasket 
seal, 304 stainless steel perforated screens and a drain/blow-off 
connection plug. 
Features
•    Flanges conform to American Cast Iron Flange Standard, Class  
250 (ANSI B16.1)
•   Body meets ASME standards
•   One-piece lead free* cast body
•   Equipped with bolted cover flange that utilizes a flat gasket seal
•   Upper and lower machined seats
•   304 Stainless steel perforated screens
•   Drain/Blow-off connection furnished with plug
•   Generous screen area and properly proportioned straining  
chamber to minimize initial pressure drop while maximizing time 
between cleanings
Specifications
A flanged, wye pattern, ductile iron strainer to be installed as indicated on the plans.  The strainer must have a one-piece cast body,  
bolted cover flange, machined seats, 304 stainless steel perforated 
screens and a drain/blow-off plug. Pressure rating no less than 
500psi (34.47 bars) WOG non-shock and 250psi (17.2 bars) WSP.   
Strainer body and flanges shall conform to American Cast Iron  
Flange Standard, Class 250 (ANSI B16.1).  Strainer shall be a Watts 
Series 77F-DI-250.
  Contractor  
  Approval  
  Contractor’s P.O. No.  
  Representative  
 ––––––––––––––––––––––––––––––––––––––––––––
 –––––––––––––––––––––––––––––––––––––––––––––
 ––––––––––––––––––––––––––––––––––––––––
77F-DI-250
Pressure – Temperature
Temperature Range: -20°F (-28.9°C) - 406°F (208°C) 
Maximum Operating Pressure:  
  500psi (34.47 bars) WOG, non-shock, @ 150°F (66°C) 
  250psi (17.2 bars) WSP @ 406°F (208°C) 
Standard Screens
2" – 3" (50 – 75mm): 3/64" perforation 
4" – 12" (100 – 300mm): 
 ––––––––––––––––––––––––––––––––––
1
/8" perforation
*The wetted surface of this product contacted by consumable 
water contains less than 0.25% of lead by weight.
Watts product specifications in U.S. 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 without prior notice and without incurring any obligation to make such changes and modifications on Watts products previously or subsequently sold.

Materials
C
E
A Body  Ductile Iron A395 
B Cover  Ductile Iron A395 
C Screen  304 Stainless Steel 
D Plug  Cast Iron, A126-B 
E Bolt/Stud  A307-B 
F Nut  A563
Pressure Drop vs. Flow
”
2
 kPa psi
A
 69 10
Pressure Drop
B
 7 1.0
D
F
 1 0.1
10  100  1000  10000 gpm
38  380  3800  38000 lpm
2”
Flow
⁄
1
2
4”
3”
5”
8”
10”
6”
12”
Dimensions 
— Weights
A
D 
Clearance 
B
for screen 
removal
C NPT
  SIZE (DN)  DIMENSIONS  WEIGHT
  A B  C D
 in. mm  in. mm in. mm  in. mm  in. mm  lbs. kgs
 2 50 87⁄8 226 61/2 165 1/2 15 91/8 232  28 13 
 2 
 3 75 11 
 4 100 14 
 5 125 17 
 6 150 18 
 8 200 21 
 10 250 27 
 12 300 31
1
⁄2 65 111⁄4 289  7 178  1 25  97/8 251  38 17
5
⁄8 295  8 203  1 25  111/4 286  54 24
1
⁄2 368 103⁄4 273  1 25  15 381  110 50
3
⁄8 441 131/2 343  11/4 32  19 483 160 73
3
/4 476 161/4 413  11/2 40 223/4 578  224 102
7
/8 556 191/2 495  11/2 40 273/4 692  468 212
1
/4 692 211/4 540  2 50  293/4 756  590 268
3
/8 797 25 635  2 50  35 889  890 404
A Watts Water Technologies Company
USA: Tel: (978) 688-1811 • Fax: (978) 794-1848  • www.watts.com
Canada: Tel: (905) 332-4090 • Fax: (905) 332-7068  • www.watts.ca 
ES-77F-DI-250    1307  © 2013 Watts