Armstrong GP-2000 Manual de instalación, uso y mantenimiento - Página 4
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Before working on the valve, make sure that the inlet strainer is clean, bypass valve is closed and
upstream and downstream pressure gauges are working properly. Refer to Figure 3-1.
Problem
Cause
Outlet
Inlet pressure is not adequate for
desired results.
Pressure
does not
Adjustment is not proper.
reach
Orifice is too large in fitting
desired
(30B).
value.
Orifice of fitting (30C) is
plugged.
Pilot valve is clogged.
Main diaphragms are damaged. Close all valves and remove fitting (30C). Open bypass
Valve size is too small and
cannot supply enough capacity.
A) Adjustment is not proper.
Secondary
pressure
B) Orifice of fitting (30B or C) is
exceeds the
plugged.
pressure
C) Dirt is either caught between
setting.
the main valve and seat or pilot
valve and seat.
D) Dirt is between main spindle
(9) and guide (10).
E) By-pass valve is not shut or is
leaking.
F) Sensing line is plugged.
G) Sensing line is not
connected.
Operation is
Orifice fitting is partially plugged. Check (30B) and (30C).
unstable.
Sensing pipe is installed at a
point where there is too much
turbulence.
Liquid is collecting in sensing
line.
Quick opening/closing valve
located too close to the outlet or
inlet PRV.
Excessive
Valve size is larger than what
was required causing valve
noise is
chatter.
present.
Pressure reduction ratio exceeds
20:1.
Fluid velocity is too high.
Automatic valve (i.e., solenoid) is
too close to PRV.
Troubleshooting Guide
Test
Maximum outlet pressure is 85% of the inlet with a
minimum DP = 7 psi.
Turn adjusting screw (27) clockwise.
Remove and check.
Close inlet valve. Remove fittings (30A) and (30B). Turn
(27) adjusting screw counterclockwise until it is loose.
Open inlet steam valve and turn (27) adjusting screw
clockwise. If fluid does not appear at (30A), pilot valve is
clogged.
valve around PRV. If fluid appears out of diaphragm casing
at (30C), diaphragm has failed.
Throttle downstream valve located downstream of sensing
line. If desired pressure can be reached after throttling
valve PRV is too small.
Turn (27) adjusting screw counterclockwise.
Remove and check.
1) Close inlet and outlet steam valves.
2) Turn (27) adjusting screw counterclockwise until
loose.
3) Remove all copper tubing from the side of the valve.
4) Open inlet steam valve.
5) If fluid appears at (30A), proceed to solution #1.
6) If fluid appears at (30B), proceed to solution #2 and
.
also see 'D' below.
7) Fluid does not appear at either part, proceed to 'E'
.
below.
If valve fails test at (30B)
(as described above in item 6) check while assembled.
Close and listen with stethoscope.
Break union and open valve.
Refer to Drawings on Page 1.
Refer to Drawings on Page 1.
Recalculate load. Check for valve chatter.
Verify inlet and outlet pressure.
Verify with PRV software (consult factory).
Visual.
4
Solution
Raise inlet pressure if possible.
Dismantle and clean.
Install proper fitting.
Clean or replace fitting.
Disassemble and clean (18) pilot
valve seat. Also, check (15) screen.
Disassemble and replace (12) main
diaphragms.
Resize and install larger valve.
Readjust.
Clean or replace fitting.
1) Tighten or loosen adjusting
.
.
screw to flush out dirt. If pilot
.
valve still leaks, clean or
.
replace it.
2) Disassemble and remove main
.
valve (it will lift out easily). If it
.
appears shiny at one point,
.
apply lapping compound and
.
lap the valve and seat (see
.
bulletin AY-768 for lapping
.
instructions).
Clean.
Repair or replace.
Clean and replace.
Install sensing line as shown on
installation drawing on Page 1.
Remove and clean or replace.
Install sensing pipe at another
location.
Slant pipe away from PRV.
Relocate PRV.
Change valve or add orifice plate to
outlet of PRV.
Use two stage reduction.
Resize station using two stage
reduction or use sound silencer
down from PRV.
Relocate.