6
Use the following procedure and accompanying illustration to inspect
the seat and clean the seat and clapper washer.
1. After removing the first check from the backflow valve body, place
it on a flat surface with the coil spring facing up.
2. To gain access to the seat and clapper rubber ring, compress the
spring (item 3) that surrounds the clapper shaft (item 1) by placing
the
3
⁄
8
" threaded rod through the two holes of the spring retaining
plate (item 2).
3. After placing the
3
⁄
8
" all-thread rod through the spring retain-
ing plate, screw the threaded rod into the holes (item 4) at the
base of spider (item 5, next to shaft). Be sure to use two nuts
on the threaded rod to tighten them into the holes. The depth of
the threaded holes should be approximately 1/2". This operation
requires the use of two pieces of threaded rod.
4. Compress the spring by loosening the top
3
⁄
8
" nut and back it off
without unscrewing the threaded rod from the spider. Place a
box end wrench or crescent wrench on the
3
⁄
8
" nut closest to the
spring retaining plate and tighten. Tighten the threaded rod and
nut evenly: put a few turns on one threaded rod nut and a few
turns on the other, repeat alternating between the two until finish.
5. During compression, the clapper slowly moves up, away from
the seat. To examine the seat, continue the spring compression
until the clapper has moved approximately 1" from the seat. This
allows debris to be removed and the seat to be examined.
6. To unload the spring compression, loosen the all-thread and then
double nut the all-thread and unscrew the rod from the spider and
shaft base.
1
2
3
4
5
6
3
⁄
8
- 16
var.
Threaded Rod
7
8
9
Check #1 Valve
8" – 10"
Inspecting and Cleaning the First Check
Tools required:
• Two pieces of
3
⁄
8
" threaded rod (approximately 14" long)
• Adjustable crescent wrench
• Pipe wrench or channel lock pliers
DANGER
!
Use extreme caution when servicing the first check!
ITEM
DESCRIPTION
1
Shaft
2
Spring retaining plate
3
Spring
4
3
⁄
8
" threaded hole (maintenance)
5
Spider
6
Spider retaining bolt
7
Seat ring
8
Clapper to shaft bolt
9
Seat ring retainer
