FEBCO Operation and Maintenance
805Y / 805YB / 805YS
Double Check Assembly (
3
/
4
" – 2")
FEATURES AND OPERATING PROCEDURES
This device consists of two independently operating poppet type check valves. Each check valve is spring loaded to maintain a minimum
of 1 PSIG differential pressure across the check in a no-flow condition. In a normal flow condition the checks open an amount correspond-
ing to the flow rate. During a backflow (backpressure) situation the seat discs close and seal to prevent any flow reversal. Sizes 3/4"
through 2" (805Y, 805YB, 805YS, 805YR) include two spring-loaded, Y-pattern bronze check valves, two bronze shut-off valves and four
testcocks for field testing. All valves are threaded type and the unit is shipped completely assembled.
GENERAL SERVICE PROCEDURES (General service instructions applicable to all sizes.)
1. Rinse all parts with clean water prior to assembly.
2. DO NOT USE ANY PIPE DOPE, OIL, GREASE OR SOLVENT ON ANY PARTS unless instructed to do so.
4. Do not force parts. Parts should fit freely together. Excess force may cause damage and render the device inoperable.
5. Carefully inspect seals, seating surfaces, etc. for damage or debris.
5. Test unit after servicing to insure proper operations.
6. Refer to applicable parts list and figures for more information.
7. A table on page 3 provides size and material information for standard parts (non-special design). These parts can usually be
purchased locally from parts distributors.
8. Some water conditions can cause a buildup of calcium or similar material deposits on some moving parts. Normally this condition
would not occur on devices used in systems with varying flow rates. The scraping action of moving parts helps to remove any deposits.
However, with devices used on static systems such as firelines, any deposits would not be scraped away and could interfere with the
check valve operation. Devices in these applications should be disassembled and inspected on a periodic basis depending on water
quality. Any deposits should be removed from the center guiding stem and bushings. Use care to avoid damage to guiding surfaces.
TROUBLESHOOTING GUIDE
Symptom #1
Check fails to hold 1.0 PSID min.
Symptom #2
Chatter during flow conditions.
Symptom #3
Low flows passing through the
mainline valve.
Cause:
A. Debris on sealing surfaces
B. Leaking shut-off valve
C. Damaged seat disc or seat ring
D. Damaged guide holding check open
E. Weak or broken spring
Cause:
A. Worn or damaged guide
Cause:
A. Mainline check fouled
Solution:
Disassemble and clean
Disassemble and clean or repair
Disassemble and replace
Disassemble and replace guide pin
and/or sleeve bushing
Disassemble and replace spring
Solution:
Disassemble and repair or replace guide
Solution:
Inspect and clean, or repair
®