TLV A-COS-10 User manual

172-65254MA-04 (A-COS-10) 22 April 2020
Pressure Reducing Valve for Air
A-COS-10
Copyright © 2020 by TLV CO., LTD.
All rights reserved

172-65254MA-04 (A-COS-10) 22 Apr 2020
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Contents
Introduction......................................................................... 1
Safety Considerations ........................................................ 2
Specifications ..................................................................... 4
Acceptable Operating Range.............................................. 4
Correct Usage of the A-COS Pressure Reducing Valve..... 5
Configuration...................................................................... 7
Installation .......................................................................... 8
Adjustment ....................................................................... 12
Maintenance..................................................................... 13
Disassembly..................................................................... 14
Reassembly...................................................................... 18
Troubleshooting................................................................ 19
Product Warranty.............................................................. 22
Introduction
Thank you for purchasing the TLV pressure reducing valve for air, A-COS.
This product has been thoroughly inspected before being shipped from the
factory. When the product is delivered, before doing anything else, check the
specifications and external appearance to make sure nothing is out of the
ordinary. Also be sure to read this manual carefully before use and follow the
instructions to be sure of using the product properly.
Using air in which matter such as condensate, scale or types of oil is
entrained can not only result in problems with the air-using equipment and in
lowered productivity, but can also lead to shortened service life for and
malfunction of the reducing valves.
The TLV pressure reducing valve for air, model A-COS, is a new reducing
valve that eliminates these problems and makes possible the supply of high-
quality air at a constant pressure.
If detailed instructions for special order specifications or options not
contained in this manual are required, please contact TLV for full details.
This instruction manual is intended for use with the model(s) listed on the
front cover. It is needed not only for installation, but also for subsequent
maintenance, disassembly/reassembly and troubleshooting. Please keep it in
a safe place for future reference.

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Safety Considerations
Read this section carefully before use and be sure to follow the instructions.
Installation, inspection, maintenance, repairs, disassembly, adjustment and valve
opening/closing should be carried out only by trained maintenance personnel.
The precautions listed in this manual are designed to ensure safety and prevent
equipment damage and personal injury. For situations that may occur as a result
of erroneous handling, three different types of cautionary items are used to
indicate the degree of urgency and the scale of potential damage and danger:
DANGER, WARNING and CAUTION.
The three types of cautionary items above are very important for safety: be sure
to observe all of them as they relate to installation, use, maintenance and repair.
Furthermore, TLV accepts no responsibility for any accidents or damage
occurring as a result of failure to observe these precautions.
Symbols
Indicates a DANGER, WARNING or CAUTION item.
DANGER
Indicates an urgent situation which poses a threat of death or
serious injury
WARNING
Indicates that there is a potential threat of death or serious injury
CAUTION
Indicates that there is a possibility of injury or equipment / product
damage
WARNING
NEVER apply direct heat to the float.
The float may explode due to increased internal pressure, causing
accidents leading to serious injury or damage to property and
equipment.
CAUTION
Install properly and DO NOT use this product outside the
recommended operating pressure, temperature and other
specification ranges.
Improper use may result in such hazards as damage to the product
or malfunctions that may lead to serious accidents. Local
regulations may restrict the use of this product to below the
conditions quoted.
DO NOT use the product in excess of the maximum operating
pressure differential.
Such use could make discharge through the air trap impossible
(blocked).
Use hoisting equipment for heavy objects (weighing
approximately 20 kg (44 lb) or more).
Failure to do so may result in back strain or other injury if the object
should fall.
Take measures to prevent people from coming into direct
contact with product outlets.
Failure to do so may result in burns or other injury from the
discharge of fluids.
Continued on the next page

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CAUTION
When disassembling or removing the product, wait until the
internal pressure equals atmospheric pressure and the surface
of the product has cooled to room temperature.
Disassembling or removing the product when it is hot or under
pressure may lead to discharge of fluids, causing burns, other
injuries or damage.
Be sure to use only the recommended components when
repairing the product, and NEVER attempt to modify the
product in any way.
Failure to observe these precautions may result in damage to the
product and burns or other injury due to malfunction or the
discharge of fluids.
Do not use excessive force when connecting threaded pipes to
the product.
Over-tightening may cause breakage leading to fluid discharge,
which may cause burns or other injury.
Use only under conditions in which no freeze-up will occur.
Freezing may damage the product, leading to fluid discharge, which
may cause burns or other injury.
Use only under conditions in which no water hammer will
occur.
The impact of water hammer may damage the product, leading to
fluid discharge, which may cause burns or other injury.

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Specifications
Install properly and DO NOT use this product outside the recommended
operating pressure, temperature and other specification ranges.
Improper use may result in such hazards as damage to the product or
malfunctions which may lead to serious accidents. Local regulations
may restrict the use of this product to below the conditions quoted.
CAUTION
DO NOT use the product in excess of the maximum operating pressure
differential; such use could make discharge impossible (blocked).
CAUTION
Use only under conditions in which no freeze-up will occur. Freezing
may damage the product, leading to fluid discharge, which may cause
burns or other injury.
CAUTION
Refer to the product nameplate for detailed specifications.
Model
Nominal Diameter
Maximum Operating
Temperature
Valve No.*
Secondary Pressure
Adjustable Range
Primary Pressure
Range
Production Lot No.
* Valve No. is displayed for products with options. This item is omitted from the nameplate
when there are no options.
Acceptable Operating Range
Model
A-COS-10
Applicable Fluid
Air
Primary Pressure Range
0.1 to 0.9 MPaG (15 to 130 psig)
Secondary Pressure Adjustable Range
0.05 to 0.7 MPaG (7 to 100 psig)
Minimum Differencial Pressure
0.05 MPa (7 psi) and larger
Maximum Operating Temperature
100 °C (212 °F)
Minimum Adjustable Flow Rate
10% of rated flow rate and larger
(1 MPa = 10.197 kg/cm2)

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Correct Usage of the A-COS Pressure Reducing Valve
Install properly and DO NOT use this product outside the recommended
operating pressure, temperature and other specification ranges.
Improper use may result in such hazards as damage to the product or
malfunctions which may lead to serious accidents. Local regulations
may restrict the use of this product to below the conditions quoted.
CAUTION
1. The product should be operated only within its specifications.
2. Installing an ON-OFF Valve (Solenoid Valve or Motorized Valve)
If an on-off valve, such as a motorized valve, is required, install it at the inlet side
of the product. If a solenoid valve is installed at the outlet of the product, its
opening and closing will cause heavy chattering and may lead to damage of the
piston and main valve. (When the on-off valve opens, the secondary pressure of
the product changes from zero to the set pressure. Passing through an area of
the reducing ratio of less than 10:1, where adjustment is impossible, chattering
occurs momentarily.)
NOTE: To prevent water hammer, it is recommended that a slow-acting
motorized on-off valve be used. In particular, if a fast-acting on-off
solenoid valve is used for frequent temperature control, the potential
water hammer effect can damage the air-using equipment and the
product.
Inlet Side
Motorized
Valve A-COS
Outlet Side
A-COS Solenoid
Valve
3. Installing a Safety Valve and a Control Valve
Safety
Valve
A-COS
Control
Valve
Air-using
Equipment
A-COS
Control
Valve
Safety
Valve
Air-using
Equipment
When installing a safety valve to protect the air-using equipment, be sure to
install it on the air-using equipment or directly before the inlet of the air-using
equipment. If the safety valve is installed on the outlet side of the product
between the product and a control valve, an eventual pressure rise could
activate the safety valve.

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4. Precautions for the Installation of Additional Fittings Before or After the product
In order to ensure stable air flow, the piping upstream and downstream of the
product must be straight runs. If the product is installed either directly before or
after an elbow or control valve, unevenness in air flow may result in chattering
and unstable pressure.
To ensure stable air flow, it is recommended that the product be installed on
straight runs of piping, as illustrated below.
①Inlet (primary side) of the product NOTE: d = pipe diameter
Maintain a straight piping run
of 10 d or more when a
manual valve, a strainer or
an elbow, etc. is installed.
(Example: if nominal size is
25 mm (1 in), have 250 mm
(10 in) or more)
Valve, Strainer,
Elbow, etc. A-COS
10 d or more
Valve, Strainer,
Elbow, etc. A-COS
Less
than
10 d
Maintain a straight piping run
of 30 d or more when an
automated valve (on-off
valve) is installed.
(Example: if nominal size is
25 mm (1 in), have 750 mm
(30 in) or more)
Automated
Valve A-COS
30 d or more
Automated
Valve A-COS
Less than
30 d
Maintain a straight piping run
of 30 d or more when
another pressure reducing
valve is installed. (Two-stage
pressure reduction)
(Example: if nominal size is
25 mm (1 in), have 750 mm
(30 in) or more)
30 d or more
A-COS
Second
Reducing
Valve
Less
than
30 d
A-COS
Second
Reducing
Valve
②Outlet (secondary side) of the product
Maintain a straight piping run
of 15 d or more when a
manual valve, a strainer or
an elbow, etc. is installed.
(Example: if nominal size is
25 mm (1 in), have 375 mm
(15 in) or more)
A-COS
15 d or more
Valve, Strainer,
Elbow, etc.
A-COS
Less than
15 d
Valve, Strainer,
Elbow, etc.
Maintain a straight piping run
of 30 d or more when a
safety valve is installed.
(Example: if nominal size is
25 mm (1 in), have 750 mm
(30 in) or more)
30 d or more
A-COS Safety
Valve
Less than
30 d
A-COS Safety
Valve
Maintain a straight piping run
of 30 d or more when a
control valve or an
automated valve (on-off
valve) is installed.
(Example: if nominal size is
25 mm (1 in), have 750 mm
(30 in) or more)
30 d or more
A-COS Control or
Automated
Valve
Less than
30 d
A-COS Control or
Automated
Valve

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Configuration
Plug (option)
No.
Name
1
Main Body
2
Separator Body
3
Trap Cover
4
Separator
5
Float
6
Float Cover
7
Trap Valve Seat
8
Separator Screen
9
Main Valve Seat
10
Main Valve
11
Piston
12
Cylinder
13
Pilot Screen
14
Pilot Screen Holder
15
Pilot Body
16
Pilot Valve
17
Pilot Valve Seat
18
Diaphragm
19
Diaphragm Support
20
Spring Housing
21
Coil Spring
22
Adjustment Screw
23
Spanner Cap
24
Plug –Sensing Line Port

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Installation
Install properly and DO NOT use this product outside the recommended
operating pressure, temperature and other specification ranges.
Improper use may result in such hazards as damage to the product or
malfunctions which may lead to serious accidents. Local regulations
may restrict the use of this product to below the conditions quoted.
CAUTION
Use hoisting equipment for heavy objects (weighing approximately
20 kg (44 lb) or more). Failure to do so may result in back strain or other
injury if the object should fall.
CAUTION
Take measures to prevent people from coming into direct contact with
product outlets. Failure to do so may result in burns or other injury from
the discharge of fluids.
CAUTION
Do not use excessive force when connecting threaded pipes to the
product. Over-tightening may cause breakage leading to fluid
discharge, which may cause burns or other injury.
CAUTION
Installation, inspection, maintenance, repairs, disassembly, adjustment and valve
opening/closing should be carried out only by trained maintenance personnel.
1. Blowdown
Before installing the product,
be sure to blow down all
piping thoroughly. If this is
not possible, perform a
blowdown using the bypass
valve.
Blowdown is especially
important for newly installed
piping or after the system
has been shut down for a
long period of time.
2. Removing Seal and Cap
Before installation, be sure to remove all protective seals and caps.
(Found in 3 locations, on the product inlet and outlets.)
3. Installation Angle
Make sure the product is installed on horizontal piping,
so that the arrow mark on the body matches the direction
of air flow and the adjustment section faces up.
Allowable inclination is 10 degrees in the fore-aft
direction and 15 degrees in the plane perpendicular to
the air flow line.
Open Close
A-COS
Open

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Small Hole
4. Spacer Installation
If spacing adjustment is necessary to
accommodate installation, install a spacer on the
outlet flange. The spacer should consist of a
spacer, gaskets, bolts and nuts. Fit gaskets to
both sides of the spacer between the product
outlet and the pipe flange. Fasten with bolts and
nuts.
5. Piping Support
Install the product, paying
attention to avoid excessive
load, bending and vibration.
Support the inlet and outlet
pipes securely.
6. Maintenance Space
Leave sufficient space for maintenance, inspection
and repair.
(Unit: mm (in))
7. Trap Outlet Pipe
For ease of maintenance, installation of a union
connection is recommended for the trap outlet pipe.
Connect the outlet pipe to a condensate return line, or
extend it to a trench. In the case of the latter, make
sure the end of the pipe is above the waterline.
8. Blowdown Valve (requires optional plug)
In an environment of heavy dirt or scale, or when the
air equipment is used only periodically, be sure to
install a strainer at the inlet of the product and a
blowdown valve on the main body.
1) Remove the plug from the main body and install a
blowdown valve.
2) Open the 10 mm (3/8 in) blowdown valve and blow
any residual dirt and scale off of the screen.
3) Periodically activate the blowdown valve to keep
the system free of dirt and scale.
100 (4)
100
(4) 100 (4)
100 (4)
400
(16) 400
(16)
Apx.
300
(12)
Remove the 3/8 in
plug (optional)
and install the
blowdown valve.
Correct
spacer location
Incorrect
spacer location

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9. Piping Size/Diffuser
If it is expected that the secondary air flow velocity will be more than 30 m/s (100
ft/s), install a diffuser in order to keep the flow velocity below 30 m/s (100 ft/s).
If the distance between the product and the air-using equipment is great, a possible
drop in pressure should be taken into consideration when selecting the piping size. In
addition, when installing the strainer, the strainer screen should be either at the3
o’clock or 9 o’clock position to prevent condensate accumulation.
Bypass Valve
Pressure Gauge
Pressure Gauge A-COS
Ball Valve Ball Valve
Bypass Valve
Straight-run Piping Lengths: (d = pipe diameter)
Upstream: 10 d or more / Downstream: 15 d or more
Ball Valve
A-COS Bypass Valve Bypass Valve
Pressure Gauge
Pressure Gauge
Ball Valve
Diffuser
10. Two-stage Pressure Reduction
Two-stage pressure reduction should be performed whenever the pressure
cannot be reduced to the desired level with the product due to operating range
limitations, such as when the reduction ratio is greater than 10:1.
A-COS
Pressure
Reducing
Valve
Bypass valve
Pressure Gauge
Inlet Inlet Side Outlet Side
Pressure Gauge
Bypass valve Safety Valve
(Relief Valve)
Pressure Gauge
Outlet
Outlet SideInlet Side
A-COS
Bypass valve
Pressure Gauge
Safety Valve
(Relief Valve)
Pressure Gauge
OutletInlet Inlet Side Outlet Side

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11. Accessories
Always install a shut-off valve, pressure gauge and bypass lines at both inlet and
outlet.
Ball valves, which will not retain condensate, are recommended for inlet and
outlet shut-off valves. The bypass pipe should be at least 1/2of the size of the
inlet (primary side) pipe.
Bypass Valve
Ball Valve Ball Valve
A-COS
Safety Valve
(Relief Valve)
Pressure Gauge
Pressure Gauge
A-COS
Pressure
Gauge

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Adjustment
Use only under conditions in which no water hammer will occur.
The impact of water hammer may damage the product, leading to fluid
discharge, which may cause burns or other injury.
CAUTION
The product should be properly adjusted for protection of the air-using equipment
against water hammer.
1. It is necessary to blow down all pipe lines thoroughly. The blowdown is especially
important if the line is new or has been shut down for a long period of time.
Take particular care to ensure that matter such as condensate and dirt does not
remain inside the air-using equipment.
(Stay clear of any pressurized blow-out from the safety valve.)
2. Make sure that the shut-off valve and the bypass valve located upstream and
downstream of the product are completely closed.
3. Remove the spanner cap, loosen the locknut and turn the adjustment screw
counterclockwise to reduce tension on the coil spring.
Loosen the locknut Loosen the
adjustment screw
Counterclockwise
4. Slowly, fully open the shut-off valve at the inlet of the product. Allow sufficient
time for condensate remaining at the inlet of the product to be discharged.
5. Slightly open the shut-off valve at the outlet of the product.
6. Turn the adjustment screw until the desired outlet pressure is obtained. Wait
several minutes.
Loosen the Adjustment Screw
Decrease Pressure
Tighten the Adjustment Screw
Increase Pressure
Counterclockwise
Clockwise
7. Slowly, fully open the shut-off valve at the outlet of the product.
8. After setup, retighten the locknut and replace the spanner cap.
9. When shutting down the system, always close the outlet shut-off valve first and
then the inlet valve.

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Maintenance
Take measures to prevent people from coming into direct contact with
product outlets. Failure to do so may result in burns or other injury from
the discharge of fluids.
CAUTION
Be sure to use only the recommended components when repairing the
product, and NEVER attempt to modify the product in any way. Failure to
observe these precautions may result in damage to the product or burns
or other injury due to malfunction or the discharge of fluids.
CAUTION
Operational Check
To ensure long service life of the product, the following inspection and maintenance
is recommended to be performed regularly.
Part
Inspection and Maintenance Frequency
Screens
(Separator and Pilot)
Disassemble and clean annually.
If there is substantial blockage, install a strainer
(approximately 60 mesh) ahead of the product.
Main Valve,
Main Valve Seat,
Pilot Valve,
Pilot Valve Seat
Replace after approximately 15,000 hours.
If there is chattering or dirt, premature wear may result.
Piston Ring
Replace after approximately 8,000 hours.
If there is chattering or if scale build-up is severe,
premature wear may result.
Piston
Replace after approximately 30,000 hours.
If hunting or chattering takes place, premature wear may
result.
Trap Valve Seat
Replace after approximately 40,000 hours.
If scale build-up is severe, blockage may occur in a short
period of time.
Diaphragm
Replace after approximately 30,000 hours.
If hunting or chattering takes place, cracks or fatigue may
develop in a short period of time.

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Disassembly
NEVER apply direct heat to the float. The float may explode due to
increased internal pressure, causing accidents leading to serious injury
or damage to property and equipment.
WARNING
Use hoisting equipment for heavy objects (weighing approximately
20 kg (44 lb) or more). Failure to do so may result in back strain or other
injury if the object should fall.
CAUTION
When disassembling or removing the product, wait until the internal
pressure equals atmospheric pressure and the surface of the product
has cooled to room temperature. Disassembling or removing the
product when it is hot or under pressure may lead to discharge of fluids,
causing burns, other injuries or damage.
CAUTION
It is a recommended practice to dismantle and inspect the product once a year for
preventive maintenance purposes. It is especially important to perform an inspection
immediately after the initial run of a new line or before or after equipment that is out
of service for a long period of time. (Installation, inspection, maintenance, repairs,
disassembly, adjustment and valve opening/closing should be carried out only by
trained maintenance personnel.)
Remove all pressure from the piping (both upstream and downstream). Then remove
inlet and outlet flange retaining bolts and nuts to permit removal of the product.
Secure the product in a vise to perform the inspection.
Disassembling the Adjustment Section
Loosen the adjustment screw completely and remove the hex bolts. Having removed
the spring housing, you will see the diaphragm support, coil spring and spring housing.
Check for seizure or any damaged screw threads.
Spanner Cap
Nameplate
Spring Housing
Diaphragm Support
Coil Spring
Spring Retainer
Ball
Adjustment Screw
Locknut
Hex Bolt

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Disassembling the Pilot Section
The diaphragm is removed by utilizing the notch in the pilot body. Loosen the pilot
valve seat with a box wrench and remove it. Lift the pilot valve spring up and out with
a pair of tweezers. Then loosen and remove the screen holder to remove the screen.
Check for any fault on the pilot valve seat, the seat of the pilot valve, flaws on the
gaskets, and clogging of the screen. Check for deformation, corrosion or faults on
the diaphragm. The diaphragm should be convex (open downward), with the printed
UP mark on the top.
Diaphragm
Pilot Valve Seat
& Gasket
Pilot Valve
Pilot Valve Spring
Gasket
Pilot Body
Notch
Pilot Screen
Pilot Screen Holder
& Gasket
Plug
Hex Bolt
Disassembling the Piston Section
Remove the pilot body after loosening and removing the hex bolts (stud bolts).
During this process, pay attention not to lose the connecting tubes (2).
Remove the piston and the cylinder from the body. Then remove the piston rings and
the tension rings from the piston. Do not apply too much force when removing the
piston rings and tension rings.
Check for the interior of the cylinder, the exterior of the piston rings, the small hole
on the piston and the cylinder gasket for any fault or abnormality.
Piston Ring
Tension Ring
Piston Ring
Tension Ring
Piston
Cylinder
Cylinder Gasket
Gasket
Connecting TubeConnecting Tube

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Disassembling the Separator and Main Valve Section
Turn the product upside down for easy dismantling of the separator and main valve.
Loosen the hex bolts and remove the separator body. Be careful, as the separator
may drop off when the product is returned to the normal attitude.
Removal of the separator and pressed-in sleeve permits removal of the main valve
spring, the main valve and screen. Loosen the valve seat with a box wrench and
remove it from the body.
Check for damage on the seating and sliding surfaces of the main valve, the
seating surface of the valve seat, the gaskets, and for clogging of the screen.
At start-up following shutdown for a long period, always blow down the piston
section of the body through the plug (option).
Disassembling the Air Trap Section
Loosen the trap cover bolts and remove the trap cover. Be careful, as hot
condensate may splash out.
Remove the float cover
bolts from the float cover to
reveal the float. Remove
the float, remove the trap
valve seat with a box
wrench.
Check to make sure that
there is no deformation of
the float, abnormality in
the trap valve seat or dirt
accumulation in the trap
cover.
Float Cover Bolt
Spring Washer
Gasket
Trap Cover
Guide Pin
Trap Cover Bolt
Trap Valve Seat
& Gasket
Protective Bushing
Float
Float Cover
Body
Gasket
Valve Seat
Main Valve
Hex Bolt
Gasket
Screen
Sleave
Corrugated Spring Washer
Separator
Separator Body
Spring Retainer
Main Valve Spring

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Cleaning
After inspection and removal of any abnormality, clean and reassemble the parts.
The following parts will require cleaning before reassembly:
Trap Cover
Piston
Float
Piston Ring
Trap Valve Seat
Cylinder
Pilot Screen
Separator Screen
Main Valve Seat
Pilot Valve
Main Valve
Pilot Valve Seat
Main Valve Holder
Adjustment Screw
It is permissible to clean using water, however cleaning with a mild detergent is
recommended for more effective cleaning.
(Coat threaded position with anti-seize after cleaning.)
Exploded View
Adjustment
Section
Pilot
Section
Piston
Section
Separator / Main
Valve Section
Air Trap
Section

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Reassembly
Assemble the unit using the same procedure as used for disassebling it; but in
reverse order. Observe the following precautions:
1. The PTFE gaskets may be re-used if free from fault, crushing or deformation.
2. Apply anti-seize to the threaded portion of screws and bolts, the spring housing,
ball and adjustment screw. Apply a small amount of anti-seize to the threads of
the valve seat, pilot valve seat and screen holder. Apply anti-seize carefully to
ensure it does not come into contact with other parts.
3. Fasten the bolts one at a time in an alternating
diagonal pattern to provide uniform seating.
4. After assembly, make sure that the piston and the
pilot guide operate smoothly without binding.
1) Fit the piston ring to the outside of the tension
ring.
2) The ring gaps should be opposite each other.
5. Standard fastening torque and the width across
flats for the tools to be used are as follows:
Part
A-COS
Connection Size
Width Across Flats
Tightening Torque
mm
(in)
mm
(in)
Nm
(lbf·ft)
Spring Housing Bolt
All
17
(21/32)
40
(29)
Pilot Valve Seat
All
19
(3/4)
70
(51)
Screen Holder
All
24
(15/16)
40
(29)
Pilot Body Bolt
15 –40
(1/2–11/2)
17
(21/32)
60
(44)
50
(2)
19
(3/4)
70
(51)
Trap Cover Bolt
15 –40
(1/2–11/2)
17
(21/32)
60
(44)
50
(2)
19
(3/4)
70
(51)
Valve Seat
15, 20
(1/2, 3/4)
36
(17/16)
100
(73)
25
(1)
41
(15/8)
125
(92)
32, 40
(11/4, 11/2)
60
(23/8)
250
(185)
50
(2)
70
(23/4)
300
(220)
Float Cover Bolt
15, 20
(1/2, 3/4)
8
(5/16)
7
(5)
25 –40
(1 –11/2)
10
(3/8)
10
(7)
50
(2)
13
(1/2)
20
(15)
Trap Valve Seat
15, 20
(1/2, 3/4)
11
(7/16)
10
(7)
25 –40
(1 –11/2)
13
(1/2)
15
(11)
50
(2)
17
(21/32)
40
(29)
(1 Nm 10 kgcm)
NOTE: -If a torque greater than that recommended is applied, the body or its
components may be damaged.
-Coat all threaded portions with anti-seize.
-If drawings or any other special documentation were supplied for the product,
any torque given there takes precedence over the values shown here.
Piston Ring
Tension Ring
Ring Gaps
Assembling the Piston Ring

172-65254MA-04 (A-COS-10) 22 Apr 2020
19
Troubleshooting
NEVER apply direct heat to the float. The float may explode due to
increased internal pressure, causing accidents leading to serious injury
or damage to property and equipment.
WARNING
When disassembling or removing the product, wait until the internal
pressure equals atmospheric pressure and the surface of the product
has cooled to room temperature. Disassembling or removing the
product when it is hot or under pressure may lead to discharge of fluids,
causing burns, other injuries or damage.
CAUTION
This product is shipped after stringent checks and inspection and should perform
its intended function for a long period of time without failure. However, should there
be any problem encountered in the operation of the product, consult the
troubleshooting guide below.
Problems are classified as follows:
1. The secondary pressure does not increase.
2. The secondary pressure cannot be adjusted or increases abnormally.
3. Hunting (fluctuation of the secondary pressure) occurs.
4. Chattering (a heavy mechanical noise) occurs.
5. Air leaks from the air trap or condensate is not discharged.
6. Abnormal noises.
Major causes for the above problems are usage under non-specified conditions
(out of specification), insufficient pressure or flow rate, and clogs by dirt and scale.
To ensure performance for a long period of time, it is recommended that the
“Acceptable Operating Range”, “Correct Usage of the A-COS Pressure Reducing
Valve” and “Adjustment” sections be reviewed.
It is a recommended practice to dismantle and inspect the product once a year for
preventive maintenance purposes. It is especially important to perform an
inspection immediately after the initial run of a new line or before or after equipment
such as a heater is out of service for a long period of time. (Installation, inspection,
maintenance, repairs, disassembly, adjustment and valve opening/closing should
be carried out only by trained maintenance personnel.)
Problem
Symptom
Cause
Remedy
The secondary
pressure does
not rise
The pressure does
not increase
No air is being supplied or
the inlet valve is closed
Check the valves and
piping at the primary side
The entrance to the
screens or strainer is
clogged
Clean or blow down
The secondary
pressure
cannot be
adjusted or
increases
abnormally
Adjustment is
difficult, and set
pressure varies
The pilot screen is clogged
Clean
There is insufficient air
flow
Check the flow, replace
the product if necessary
The piston is clogged
with dirt
Clean
Check the piston ring
The piston ring is worn
Replace with a new piston
ring
Continued on the next page