Watts LF909 - Manual (Page 5)

5
Servicing First and Second Checks
Sizes: 2 1 ⁄
2
" – 10" (65-250mm)
1. Remove the hatch cover bolts. NOTE: The 909 is designed so
that when the bolts are backed off 1 ⁄
2
", all the spring load is
re leased from the cover and retained by the check module.
CAUTION !
Be sure to verify this before removing all the bolts.
2. Lift the check valve module straight out taking care not to hit
and damage the seating.
3. The seat ring may be removed and replaced by pulling out the
two wire retainers on sizes 4" – 10" (100 – 250) while on sizes
2 1 ⁄
2
" – 3" (65 – 80mm), one quarter turn twist removes seat. The
wire retainers are 10” long. One is drawn out clockwise and the
other is drawn out counterclockwise.
4. With the retainer wires removed, the seat ring can be lifted
straight up and removed.
CAUTION !
5. The check valve spring is in compression. The spring load is
captured by the two spring retainers and the stem. The spring
re tainers are not to be removed for servicing. If there is a need
to re place the spring, spring retainer or stem, an assembled
module must be obtained from the factory. These modules are
not interchangeable, be sure to replace the first check with a
first check mod ule and the second check with a second check
module.
6. To replace the disc on sizes 2 1 ⁄
2
" – 4" (65 – 100mm) simply
remove the re tain ing nut or for sizes 6” – 10” (150 – 250mm)
remove the allen head socket screws. Reverse this procedure to
install the new disc.
*Disc & Spring
As sem bly
seat
seat O-ring
cover O-ring
2 1 ⁄
2
" – 3" (65 – 80mm)
*disc & spring
as sem bly
Retainer wire
seat O-ring
cover O-ring
4" – 10" (100 – 250mm)
lower stem
O-ring (6” only) seat
disc
For further details contact your tech ni cal sales representative, see back page.
No special tools
required to service
Series 909
First and second checks
are not interchangeable
First
check
second
check Relief
Valve
909OSY/
LF909OSY
WARNING !
*Spring as sem bly is factory assembled. DO NOT DIS AS SEM BLE