User Guide

ManualsBrandsFebco ManualsBackflow Preventers6" Configurable Design Double Check Valve Assembly (Lead Free)

IOM-F -DC/DCDA

INSTALLATION, OPERATION, MAINTENANCE

Maintenance Manual

Double Check and Double Check Detector Assemblies

Series 850, 856, 870V & 876V

⁄2" - 10" (65 – 250mm)

Read and understand this manual prior to installing,

operating or servicing this equipment.

Table of Contents

Features and Operating Procedures ................................2

How to Order Parts .............................................2

Trouble Shooting Guide..........................................3

Vandalism.....................................................3

Testing .......................................................3

Freeze Protection Procedures.....................................4

General Service Procedures ......................................4

Service Procedures for Models 850, 856, 870V & 876V (2

⁄2" - 10") .......6

Service Procedures for Model 805YB —

⁄4" Bypass ...................7

Parts Selection Guide Model 850/856 (2

⁄2" - 10")......................8

Parts Selection Guide Model 870, 870V / 876, 876V (2

⁄2" - 10") .........9

Parts Selection Guide .......................................10-11

Series 850

Series 876V

Summary of content (12 pages)

PAGE 1
IOM-F -DC/DCDA INSTALLATION, OPERATION, MAINTENANCE Maintenance Manual Double Check and Double Check Detector Assemblies Series 850, 856, 870V & 876V 21⁄2" - 10" (65 – 250mm) Series 850 Series 876V Table of Contents Features and Operating Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 How to Order Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PAGE 2
MAINTENANCE MANUAL SERIES 850, 856, 870V & 876V 21⁄2"- 10" (65 – 250mm) Feature and Operating Procedures Double Check Valve Assembly Operation How to Order Parts/Repair Kits The FEBCO Double Check Valve Assemblies consist of two independently operating, spring loaded check valves. The pressure drop across the first check valve is approximately 1.0 psig with no flow. The pressure drop across the second check valve is also 1.0 psig with no flow.
PAGE 3
MAINTENANCE MANUAL SERIES 850, 856, 870V & 876V 21⁄2"- 10" (65 – 250mm) Troubleshooting Symptom #1 Check fails to hold 1.0 psid minimum Cause: A. Debris on sealing surfaces B. Leaking shutoff valve C. Damaged seat or seat disc D. Spring stem not moving freely Solution: Inspect and clean Inspect and clean, or repair Disassemble and replace Inspect for debris or damage Symptom #2 Chatter during flow conditions Cause: A.
PAGE 4
MAINTENANCE MANUAL SERIES 850, 856, 870V & 876V 21⁄2"- 10" (65 – 250mm) Freeze Protection The Double Check Backflow Prevention Assembly may be subject to damage if the internal water is allowed to freeze. The unit must be protected from freezing using a heated enclosure, insulation using heat tape, or other suitable means. The unit must always be accessible for testing and maintenance. If the system will be shut down during freezing weather, use the following procedures to drain internal passages.
PAGE 5
MAINTENANCE MANUAL SERIES 850, 856, 870V & 876V 21⁄2"- 10" (65 – 250mm) General Service Procedures 1⁄2" - 10" (15-250mm) 1. FEBCO backflow prevention assemblies can be serviced with standard tools and are designed for ease of maintenance. The assemblies are designed to be serviced in line, so the unit should not need to be removed from the line during servicing. NO special tools are required. 5. Carefully inspect seals and seating surfaces for damage or debris.
PAGE 6
MAINTENANCE MANUAL SERIES 850, 856, 870V & 876V 21⁄2"- 10" (65 – 250mm) Service Procedures for Series 850, 856, 870V & 876V 21⁄2"-10"(65-250mm) Check Valve Disassembly and Reassembly 1. Spring Module Removal a. Slowly close outlet shutoff valve and inlet shutoff valve. Bleed residual pressure by opening #4, #3, and #2 test cocks (See Page 11 for test cock location). b. Remove cover bolts, removing the two bolts last that are located next to the retainer pin. Remove cover.
PAGE 7
MAINTENANCE MANUAL SERIES 850, 856, 870V & 876V 21⁄2"- 10" (65 – 250mm) Repair Parts 850 / 856 21⁄2" – 10" (65 – 250mm) Double Check / Double Check Detector Assemblies #1 Inlet Shutoff Valve First Check Test Cock #3 Test Cock #1 #2 Outlet Shutoff Valve Second Check Test Cock #4 Test Cock #2 Test Cock #2 Item Description Style Size 21⁄2" & 3" (65 – 80mm) 4" (100mm) 6" (150mm) DISC ASSEMBLY N-Shape Part # 905182 905153 905154 Items 6, 16, 17 Only SINGLE SPRING MODULE 850 Part # 905142 905143 905144 I
PAGE 8
MAINTENANCE MANUAL SERIES 850, 856, 870V & 876V 21⁄2"- 10" (65 – 250mm) Repair Parts 870, 870V / 876, 876V 21⁄2" – 10" (65 – 250mm) Double Check / Double Check Detector Assemblies Test Cock #3 Test Cock #4 First Check Second Check Test Cock #2 Test Cock #1 #2 Outlet Shutoff Valve #1 Inlet Shutoff Valve Item Description DISC ASSEMBLY Items 6, 16, 17 (10", Item 6 only) SINGLE SPRING MODULE Items 5.1, 7, 8, 9, 9.1, 10, 11, 12, 12.1 CHECK REPLACEMENT KIT Items 2.
PAGE 9
MAINTENANCE MANUAL SERIES 850, 856, 870V & 876V 21⁄2"- 10" (65 – 250mm) Service Procedures for Series 805YB — 3⁄4" Bypass 1. Bypass Check Valve Inspection/Repair Series 805YB 3⁄4". c. If the seat disc has been severely cut along the seat ring diameter, the assembly is being subjected to extremely high back pressure from thermal water expansion, water hammer or other causes of excessive water pressure. Seat discs damaged in such a manner should be replaced and not turned over to be reused. a.
PAGE 10
MAINTENANCE MANUAL SERIES 850, 856, 870V & 876V 21⁄2"- 10" (65 – 250mm) Repair Parts 805YB and Bypass Item 1 7 8 9 10 11 12 13 30 35 36 40 40.1 40.2 40.3 Item 300 301 302 303 305 309 311 312 314 315 316 317 Part No. 905-042 Part No. 905-044 Part No.
PAGE 11
MAINTENANCE MANUAL SERIES 850, 856, 870V & 876V 21⁄2"- 10" (65 – 250mm) FEBCO Performance, Value and Quality FEBCO MasterSeries® 21⁄2" - 10"(65-250mm) Double Check Detector Assembly Reduced Pressure Assembly Series 870V Series 876V Series 880V Series 870V Series 876V Series 880V Series 850 Series 856 Series 860 Conventional In-Line Vertical "N" - Shape Double Check Assembly For nearly half a century, customers have looked to FEBCO for quality products, reliable low head-loss performance, and
PAGE 12
For additional information, visit our web site at: www.FEBCOonline.com Limited Warranty: FEBCO warrants each product to be free from defects in material and workmanship under normal usage for a period of one year from the date of original shipment. In the event of such defects within the warranty period, the Company will, at its option, replace or recondition the product without charge.