Febco 850 Series Maintenance Manual Download Page 1

IOM-F-DC/DCDA

I N S T A L L A T I O N ,   O P E R A T I O N ,   M A I N T E N A N C E

Maintenance Manual

Double Check and Double Check Detector Assemblies

Series 850, 856, 870V & 876V 

2

1

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

1

2

" - 10")  .  .  .  .  .  .  .6

Service Procedures for Model 805YB — 

3

4

" Bypass  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .7

Parts Selection Guide Model 850/856 (2

1

2

" - 10") .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .8

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

1

2

" - 10")  .  .  .  .  .  .  .  .  .9

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

Series 850

Series 876V

Summary of Contents for 850 Series

Page 1: ...cing 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 21 2 10 6 Service Procedures for Model 805YB 3 4 Bypass 7 Parts Selection Guide Model 850 856 21 2 10 8 Parts Selection Guide Model 870 870V 876 876V ...

Page 2: ...lled in the vertical orientation must include vertical support under the second check body section Double Check Detector Assemblies Bypass Operation All low flow demands up to a minimum of three GPM are to pass only through the bypass assembly All flows above three GPM will pass through both the bypass and main line valve without accurate meter registration How to Order Parts Repair Kits 1 Locate ...

Page 3: ...orrectly The assembly should be tested at time of ini tial installation after servicing or maintenance and at least annually there after Acceptable test procedures are published by Foundation for Cross Connection Control and Hydraulic Research at the University of Southern California USC The American Water Works Association AWWA The American Society of Sanitary Engineering ASSE Series 5000 and the...

Page 4: ... check module until all water inside valve drains back out through inlet drain 7 If you blowout the piping downstream of the backflow assembly using compressed air Connect the air supply to the outlet drain and close the outlet ball valve After clearing the system with air partially open the outlet ball valve Leave all drain valves testcocks and ball valves in half open half closed position for th...

Page 5: ...ng to help hold O ring in place during reassembly Series 870V and 876V Apply a thin coating of the lubricant supplied in the repair kit to the O ring groove in the 2 check body and position the O ring in the groove 5 Carefully inspect seals and seating surfaces for damage or debris If the check valve seat disc has been severely cut at the seat ring diam eter the assembly has been subjected to extr...

Page 6: ...heck disc stem threads Lift the arm and remove the check disc Item 6 Inspect sealing surface for debris or damage Replace check disc if necessary NOTE When jam nut Item 16 is tight check disc is designed to wobble 3 Seat Ring Assembly Removal NOTE Remove the seat ring assembly only if the seat ring Item 3 or arm Item 4 appear to be worn or damaged a Remove locknuts Item 3 4 See above drawing NOTE ...

Page 7: ...57 905158 905159 905160 Items 3 3 1 3 2 3 4 4 4 1 4 2 5 RUBBER PARTS KIT ALL Part 905249 905163 905164 905165 Items 2 1 3 1 6 15 26 35 35 1 45 45 1 COVER ASSEMBLY With Bulkhead Part 905167 905168 905169 905170 Items 2 2 1 15 Fitting TAPPED Part 905376 905377 905378 905379 BULKHEAD FITTING FOR COVER 850 Part 905275 905277 Items 43 1 45 1 46 1 47 1 856 Part 905275 905277 BULKHEAD FITTING FOR BODY 85...

Page 8: ...5 26 35 35 1 45 45 1 COVER ASSEMBLY Inlet Check ALL Part 905167 905168 905169 905170 905171 Items 2 2 1 15 COVER ASSEMBLY Outlet Check ALL Part 905244 905245 905246 905247 905248 Items 2 2 1 15 BULKHEAD FITTING FOR COVER 870 Part 905275 905277 Items 43 1 45 1 46 1 47 1 870V 876 Part 905275 905277 876V BULKHEAD FITTING FOR BODY 870 Part 905276 905277 Items 43 45 46 47 870V 876 Part 905277 876V Bulk...

Page 9: ...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 3 Check Seat Ring Replacement a The seat rings are threaded into the body with an O ring seal against the body Remove only if the sealing edge is damaged Using an inside pipe wrench 1 inch IPS size grip the inside surface of the seat ring and loosen the part b ...

Page 10: ...c Nitrile 11 Washer Stainless Steel 12 Screw Stainless Steel 13 Spring Stainless Steel 30 Test Cock Bronze 35 Seat Ring Bronze 36 O ring Buna N 40 Ball Valve Bronze 40 1 Ball Valve Bronze 40 2 Ball Valve w tap Bronze 40 3 Test Cock Bronze Item Description Materials 300 Water Meter 301 Nipple Brass 302 Nipple Brass 303 Nipple Brass 305 Nipple Brass 309 Elbow Bronze 311 Elbow Bronze 312 Fitting Bron...

Page 11: ...head loss Cast ductile iron bodies for lighter weight Lowest installed cost Saves on labor and material Choice of cost saving N Shape designs revolutionary vertical designs or conventional in line designs Contact a FEBCO representative today for product literature and technical specifications on FEBCO MasterSeries backflow prevention products MAINTENANCE MANUAL SERIES 850 856 870V 876V 21 2 10 65 ...

Page 12: ...he sole and exclusive remedy for breach of warranty and the Company shall not be responsible for any incidental special or consequential damages including without limitation lost profits or the cost of repairing or replacing other property which is damaged if this product does not work properly other costs resulting from labor charges delays vandalism negligence fouling caused by foreign material ...

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