GP-1000 IOM

GP-1000 IOM
Bulletin No. AY-114-A
Model GP-1000
Pressure Reducing Valve
For Steam Service
Installation and Maintenance Instructions
This bulletin should be used by experienced personnel as a guide to the installation of the Model GP-1000 Pressure Reducing
Valve. Selection or installation of equipment should always be accompanied by competent technical assistance. You are
encouraged to contact Armstrong International, Inc. or its local representative for additional information.
Installation Hints
Step 1. An Armstrong inverted bucket steam trap is
recommended to drain condensate at the inlet of the pressure reducing valve (PRV).
Step 2. An Armstrong 100 mesh Y strainer with blowdow
valve should be installed before the PRV to reduce the chance of dirt fouling.
Step 3. Pressure gauges should be installed before and after the PRV.
Step 4.
Step 5. Do not install quick opening or closing valves
downstream of PRV.
Step 6. Install the PRV with the flow in the direction of the
arrow on the body.
Step 7. Piping immediately downstream of PRV should be expanded to account for low pressure expansion of steam. (Reference Catalog 326)
Piping a by-pass line with a globe valve around the PRV will allow system operation while the PRV is being serviced. It is also recommended to flush out system prior to start-up.
GP-1000 Startup and Adjustment Procedures
Improper adjustment of the pressure reducing valve may cause hunting, improper control and possible damage to the valve itself.
Adjust the valve as follows:
Step 1.
Close the gate valves before and after the pressure
reducing valve and blowdown the strainer. If strainer
blowdown valve is not available blowdown can be
done through the bypass line, adjusting the
opening ofthe bypass globe valve so as not to blow
the safety relief valve. After draining, be sure to close
the bypass globe valve.
Step 4. Slowly open the inlet side gate valve to the full open position, and open the outlet side gate valve enough so that a little fluid can flow through.
Step 5. Slowly turn the adjusting screw clockwise until
desired pressure is obtained while watching the
pressure gauge at the outlet side.
Step 2. Loosen the lock nut and adjusting screw to relieve the tension on the adjusting spring.
Step 6. Slowly open the outlet side valve to the full
open position.
Step 3: Adjustment must be made while steam is being
consumed at least 1/2 to 3/4 of maximum flow
for best results.
Step 7. After adjustment, tighten the lock nut to secure
the adjusting screw.
Troubleshooting Guide
The desired
pressure cannot
be obtained.
The outlet
pressure rises
higher than the
specified pressure.
Abnormal noise
is heard
The inlet pressure is too low or too high.
Change the pressure to the appropriate level.
The strainer (28) in the pilot body is clogged by foreign matter.
Disassemble and clean the strainer.
The piston-cylinder, clearance is clogged by foreign matter.
Disassemble and clean the piston and the cylinder. If a flaw is found,
refinish the surface by usinf a file or sand paper.
The valve is smaller than what is required.
Change to the appropriate valve size.
The adjustment is not appropriate.
Readjust according to the adjustment procedure.
The inlet strainer is clogged by foreign matter.
Disassemble and clean the strainer.
The pressure gauge is not functioning properly.
Replace the gauge.
The main valve or valve seat is contaminated by foreign matter.
Disassemble and clean the valve or seat.
The pilot valve or pilot valve seat is contaminated by
foreign matter.
Disassemble and clean the valve or seat.
The piston-cylinder clearance is clogged by foreign matter.
Disassemble and clean the piston and cylinder.
The by-pass valve is leaking.
Repair or replace the bypass valve.
The valve size is larger that what is required.
Install the correct size valve.
The reducing ratio is greater than 20:1.
Reduce pressure by staging with second PRV.
Water hammer.
Install a steam trap at the reducing valve inlet.
There is a fast closing valve near the PRV.
Provide as long a distance as possible between the two valves.
Spring or diaphragms are damaged.
Replace damaged springs or diaphragms.
Caution: Be sure that the isolation valves at inlet and outlet side of pressure reducing valve are closed and all internal
pressure has been relieved before disassembly of the valve.
Pilot Valve Disassembly
1. Loosen the lock nut (10) and turn the adjusting
screw (9) to release the spring (8) no compression.
2. Remove the bolts (33) of the spring chamber (4). Remove the spring chamber, spring, top spring plate (6), bottom spring plate (7), and diaphragm (5).
3. Remove the pilot valve assembly (19 and 20).
Main Valve Disassembly
1. Remove the bolts (35) of the bottom cover (3). Remove the bottom cover, main valve spring (13), and main valve (11).
2. Make sure the sliding movement of piston and cylinder
is smooth.
Piston Disassembly
1. Remove the bolts (34) of the pilot body (2). Pick up the spindle (18), and remove the piston ring (16) and the inner ring (17).
1. Make sure that the main valve and seat, pilot valve and seat have no flaws. Even a small flaw on the valve or
seat may cause leaking.
3. Be sure to replace all gaskets and diaphragms.
4. Reassemble in the reverse order of disassembly.
Armstrong Pressure/Temperature Control Group, 221 Armstrong Blvd., P.O. Box 408, Three Rivers, Michigan 49093 - USA Ph: (269) 279-3600 Fax: (269) 273-8656
5/09 Printed in U.S.A.
Bulletin AY-114-A
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