User Guide

Table Of Contents

FEBCO Model 850 / 850U (

" - 2") Page 3

FLOW á

Test Cock

Check Module

CUT-A-WAY DRAWING

Note: Union End Ball Valves Not Shown

GENERAL SERVICE PROCEDURES

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.

Suggested Tool Kit Model 850 (

" - 2")

• 1 crescent wrench • 1 medium Phillips screw driver

• 1 medium standard screw driver • Box/open end wrench

• Differential pressure test kit

2. The most common cause of check fouling is dirt and debris in the seating areas. The line should be flushed

clean of debris before installation of the assembly. To flush the line after installation of the assembly, slowly

close the inlet shut-off valve, remove the cover and spring assemblies of both check valves and open the

inlet shut-off valve to allow sufficient flow of water through the assembly to clear all sand, debris, etc. from

the line. If debris in the water continues to cause fouling, a strainer may be installed upstream of the

assembly (check local codes).

3. Rinse all parts with clean water before reassembly.

4. Carefully inspect seals, and seating surfaces for damage or debris. If the check valve seat disc has been

severely cut at the seat ring diameter, the assembly has been subjected to extremely high and repeated

back pressure. Either thermal water expansion or water hammer are the most likely causes. If back pres-

sure persists, consider installation of a pressure relief valve downstream of the assembly.

5. Use caution to avoid damaging any guiding surfaces while handling parts. Do not force parts together. The

o-ring seals used in FEBCO assemblies require only a small tightening force to insure a positive seal.

6. Test unit after servicing in accordance with locally approved test methods to insure proper operation (see

page 9 for more details).

7. Refer to applicable exploded drawings and parts lists (pages 6-8) for visual aid information.

8. Use food grade petroleum jelly as a lubricant as instructed in this manual.