Cashco 31-N - Manual (Page 4)

IOM-31-N 4
1 Product of Fisher Scientifi c Company
SECTION VI
VI. MAINTENANCE
A. General:
1. Maintenance procedures hereinafter are based
upon removal of the regulator from the pipeline
where installed.
2. Owner should refer to owner’s procedures for
re mov al, handling and cleaning of re us able
parts, the dis pos al of non-reusable parts, i.e.
gaskets, suitable sol vents, etc.
3. If desired, gaskets may be oiled, or coated with
gasket sealant or thread sealing com pound,
provided the sealant is compatible with the fl u-
id. (See below for “oxygen cleaned” valves.)
4. Valves originally supplied as “special cleaned”
(Opt-56) are assembled using special seal ant,
Fluorolube GR-362
1 , or equivalent. Cash co,
Inc., rec om mends fol low ing factory cleaning
specifi cation #S-1542, or equiv a lent. Contact
factory for details.
5. When directions such as upwards, down wards,
leftwards or rightwards are given, they are with
respect to Figures 5 and 6.
When counter clockwise (CCW) or clock wise
(CW) ro ta tions are indicated, they are with
respect to:
a. Spring Chamber – as viewed from above
looking down towards the closing cap or
its normal location.
b. Body – as viewed looking into the body
cavity with the upper case assembly re-
moved.
B. Diaphragm Replacement:
1. Install the body (1) in a vise with the spring
chamber (4) directed upwards.
2. Remove closing cap (5). Relax range spring
(17) by turning adjustment screw (18) CCW
until removed from spring cham ber (4); count
number of full revolutions and record below.
No. of revolutions to remove ad just ment
screw (18) ____________________ .
3. Paint or embed a match mark between lower
case (3) and spring chamber (4) at fl ange
O.D.
4. Remove all diaphragm fl ange nuts (10) and
screws (9).
5. Remove spring chamber (4) and range spring
(17).
6. Pry up the edges of the diaphragm (12) from
around the pe rim e ter of the lower case (3)
diaphragm fl ange to assure that the diaphragm
(12) is not “sticking” to the lower case.
7. Grasp stop post (19) and with hand carefully
lift up wards and to the right to disengage link-
age lever (21) from cir cu lar opening of lower
di a phragm plate (20). Fully remove diaphragm
sub-assembly (DSA) from lower case.
8. Place the “ear” of the lower diaphragm plate
(20) into a soft jawed vise and fully secure,
with stop post (19) pointed upwards. Place a
wrench on the hex surface of stop post (19)
and loosen by rotating CCW (viewed from
above).
9. Grasp upper diaphragm plate (13) with fi n gers
and continue to loosen stop post (19) until re-
moval. Finger remove washer (16), and nylon
bushing (15). Lift upper diaphragm plate (13),
together with stuck-on diaphragm (12) away
from lower diaphragm plate (20), and place
on bench top.
WARNING
SYSTEM UNDER PRESSURE. Prior to performing any
maintenance, isolate the regulator from the system and
relieve all pressure. (Including the External Sensing
line when specifi ed.) Failure to do so could result in
personal injury.
WARNING
SPRING UNDER COMPRESSION. Prior to re mov ing up-
per case, relieve spring compression by removing the
ad just ing screw. Failure to do so may result in fl ying parts
that could cause personal injury
.