IOM-POSR-1
9
5. Close needle valve at outlet connection of main
valve (MV). Crack open the needle valve at
the pilot valve (PV) outlet.
6. Rotate adjusting screw (19) of pilot valve (PV)
CW (viewed from above adjusting screw) until
a point of high resistance occurs; this should
correspond to the diaphragm (12) pushing
against the body's (1) down trav el stops.
Record the number of rev o lu tions the ad just ing
screw was rotated in the box below:
No. of revolutions the adjusting screw
was ro tat ed ______________.
7. Slowly pressurize the inlet of the main valve
(MV) and pilot valve (PV) to 100 psig (6.9
Barg).
NOTE:
If the pilot valve (PV) has any other
range spring (15) above 5–15 psig (.34–1.03
Barg), the test pressure can be raised to 200
psig (13.8 Barg).
8. Using a solution of leak detection fluid and
water, apply a liberal amount of the solution
to cover each external joint, in clud ing the
thread ed fittings (20), tub ing (21) and the
interconnecting pipe nipple (19) threaded
con nec tions. Wait a minimum of five minutes to
allow sufficient time for a leak to form bubbles.
Repeat this procedure with a second five
minute wait.
9. Identify and mark any observed leakage.
Dis as sem ble down to the point of leakage
and determine the cause of the leak. Repair
and reassemble per instructions in Section
VI. Retest per Section VII.
10. Shut off pressure to inlet con nec tion of
main valve (MV) and re move all leak testing
equip ment. Reset the adjusting screw (19)
back to its normal setpoint by rotating the
screw (19) CCW (viewed from above) the
same num ber of revolutions re cord ed in Ar ti cle
6. pre vi ous, this sub-section.
6. Relax the range spring (15) by rotating the
ad just ing screw (19) CCW (viewed from above
ad just ing screw until fully loose. Keep track
of the num ber of rev o lu tions in the box below:
No. of Revolutions adjusting screw ro tat ed:
__________________.
7. Connect temporary air supply with in-line
ad just able airset regulator to P
2
outlet of pilot.
Slow ly pres sur ize the pilot valve (PV) while
ob serv ing the jar with water. Bring pres sure
to 50 psig (3.4 Barg). Wait a minimum of five
min utes. Observe for leak age of bubbles in the
water jar. If the number of bubbles is greater
than one (1) per minute, the leakage is at the
point where trim re place ment is rec om mend ed.
(Rec om mend pres sure in teg ri ty test per Sub-
Section D. here in.)
8. Remove leak test apparatus. Re in stall brass
fit tings (20) using suitable thread sealant.
Reinstall all tubing (21).
C. Seat Leakage – Main Valve (MV):
Seat leakage rate for main valve cylinder
(3.1) and piston (3.2) should be equiv a lent
to ANSI/FCI 70-2, Class IV (approaches
0.1% of rated valve capacity).
D. Pressure Integrity Leak Test:
1. Test pilot valve (PV) and main valve (MV)
assembled together with all interconnecting
pipe (19), tubing (21) and fittings (20).
2. Insert tapped pipe plugs with hose fittings to
both inlet and outlet body (1) connections.
3. Install temporary hoses with tight shutoff
in stru ment needle valves at outlet connection
of main valve (MV) and of the pilot valve (PV).
4. Connect temporary air supply with in-line
adjustable airset regulator to inlet connection
of main valve (MV).
VIII. TROUBLE SHOOTING GUIDE
SECTION VIII
Possible Causes
Remedies
A.
Wet steam or condensate at the inlet.
A.
Install a steam trap on the inlet side of the regulator.
B.
Clogged pilot valve screen.
B.
Clean or replace. Blowdown inlet drip leg. Install upstream strainer, if
severe.
C.
Regulator oversized for flow conditions.
C.
Install correct size.
D.
Insufficiently sloped line.
D.
Move tap from top of pipe to side; or, increase sensing tube to 3/8" OD.
1. Erratic or Noisy Operation.
