TLV COSPECT User manual

172-65254M-03 (A-COS-10) 27 October 2008
Pressure Reducing Valve for Air
COSPECT
A-COS-10
Copyright © 2008 by TLV CO., LTD.
All rights reserved
ISO 9001/ ISO 14001
Manufacturer
Kakogawa, Japan
is approved by LRQA LTD. to ISO 9001/14001

172-65254M-03 (A-COS-10) 27 Oct 2008
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Contents
Introduction .......................................................................... 1
Safety Considerations.......................................................... 2
Specifications....................................................................... 4
Acceptable Operating Range............................................... 4
Correct Usage of the COSPECT Pressure Reducing Valve 5
Configuration........................................................................ 7
Installation............................................................................ 8
Adjustment ......................................................................... 11
Maintenance ...................................................................... 12
Disassembly....................................................................... 13
Reassembly ....................................................................... 17
Troubleshooting ................................................................. 18
Product Warranty ............................................................... 21
Introduction
Thank you for purchasing the COSPECT pressure reducing valve for
air.
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.
Air-using equipment can achieve its intended efficiency only if the air being
used is very dry. 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 COSPECT pressure reducing valve for air, model A-COS, is a new
reducing valve that eliminates these problems and makes possible the supply
of very dry air at a constant pressure.
If detailed instructions for special order specifications or options not contained
in this manual are required, please contact 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 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.
Safety considerations are 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 trap 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.
* Valve No. is displayed for products with options. This item is omitted from the nameplate when
there are no options.
Acceptable Operating Range
Use Model
Primary
Pressure
Range
(MPaG)
Secondary
Pressure
Adjustable Range
(MPaG)
Minimum
Differencial
Pressure
(MPa)
Maximum
Operating
Temperature (°C)
Minimum
Adjustable Flow
Rate
For Air A-COS-10 0.1 - 0.9 0.05 - 0.7 0.05 100 10% of rated flow
rate
Primary Pressure Range
Model
Serial Numbe
r
Nominal Diamete
r
Maximum Operating
Temperature
Valve No.*
Secondary Pressure
Adjustable Range

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Correct Usage of the COSPECT 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 COSPECT should be operated only within its specifications.
2. Installing an ON / OFF Valve (Solenoid Valve or Motorized Valve)
減圧弁
電動弁
入口側
出口側
電磁弁
減圧弁
If an on-off valve, such as a motorized valve, is required, install it at the inlet side
of the COSPECT. If a solenoid valve is installed at the outlet of the reducing
valve, 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 reducing valve 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.)
3. Installing a Safety Valve
減圧弁
安全弁
制御弁
エア使用装置
安全弁
エア使用装置
制御弁
減圧弁
When installing a safety valve to protect the air equipment, be sure to install it on
the air equipment or directly before the inlet of the air equipment. If the safety
valve is installed on the outlet side of the COSPECT between the COSPECT and
a control valve, an eventual pressure rise could activate the safety valve.
Motorized
Valve COSPECT
Inlet Side
Safety
Valve
Equipment
COSPECT
Outlet Side
Solenoid
Valve
Equipment
Safet
y
Valve
Control
Valve
Control
Valve
COSPEC
T
COSPEC
T

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4. Precautions for the Installation of Additional Fittings Before or After the Reducing
Valve
In order to ensure stable air flow, the piping upstream and downstream of the
reducing valve must be straight runs. If a pressure reducing valve 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 pressure reducing valve be
installed on straight runs of piping, as illustrated below.
①Inlet (primary side) of the pressure reducing valve 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, have 250 mm or more)
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, have 750 mm or more)
②Outlet (secondary side) of the pressure reducing valve
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, have 375 mm or more)
Maintain a straight piping
run of 30 d or more when a
safety valve is installed.
(Example: if nominal size is 25
mm, have 750 mm or more)
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, have 750 mm or more)
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, have 750 mm or more)
Valve, strainer,
elbow, etc.
COSPECT
10 d or
more
COSPECT
Less
than
10 d
COSPECT
Automatic
Valve
30 d or more
Automatic
Valve
Less than
30 d
COSPECT
15 d or more
COSPECT
COSPECT
30 d or more
Safety
Valve COSPECT
Safety
Valve
COSPECT
30 d or more
Second
Reducing
Valve
Control or
Automated
Valve
30 d or more
COSPECT
COSPECT
COSPECT
Less than
15 d
Less than
30 d
Less than
30 d
Second
Reducing
Valve
Control or
Automated Valve
COSPECT
Valve, strainer,
elbow, etc.
Less than
30 d

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Configuration
No. Name
1 Main Body
2 Trap 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 Valve 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
Plug (option)

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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 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
Installation, inspection, maintenance, repairs, disassembly, adjustment and valve
opening/closing should be carried out only by trained maintenance personnel.
1. Blowdown
Before installing the COSPECT unit, 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
Install the COSPECT vertically, so that the arrow
mark on the body points horizontally in the direction
of air flow.
Allowable inclination is 10 degrees in the fore-aft
direction and 15 degrees in the plane perpendicular
to the air flow line.
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 COSPECT
outlet and the pipe flange. Fasten
with bolts and nuts.
C
orrect
S
pacer
Location
Incorrect
S
pacer
Location
Blowdown Using
Bypass Valve
Blowdown
Piping Before
Installation

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5. Piping Support
Install the COSPECT, 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.
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 COSPECT and a
blowdown valve on the main body.
1. Remove the plug from the main body.
2. Install the 10 mm blowdown valve.
3. Open the blowdown valve and blow any residual
dirt and scale off of the screen.
4. Periodically activate the blowdown valve to keep
the system free of dirt and scale.
Small Hole
Remove the ⅜”
plug (optional)
and install the
blowdown valve
(
Unit: mm
)
approx.

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9. Piping Size
If it is expected that the secondary air flow velocity will be more than 30 m/s,
install a diffuser in order to keep the flow velocity below 30 m/s.
ディフューザ
減圧弁 減圧弁
0.2m以上
減圧弁
Straight-run Piping Lengths: Upstream = 10 d or more; Downstream = 15 d or more
(d = pipe diameter)
10. 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 ½ of the size of the inlet
(primary side) pipe.
COSPECT has a built-in strainer, however in case an external strainer is installed,
it should be installed ahead of COSPECT and the strainer should be installed
horizontally with the basket at the 3 or 9 o’clock position in order to prevent
condensate accumulation.
ボールバルブ ボールバルブ
ボールバルブ
減圧弁
減圧弁 減圧弁
Diffuser
Ball Valve
Pressure Reducing Valve
More than 0.2 m
Pressure Reducing Valve
Ball Valve
Ball Valve
Pressure Reducing Valve
Pressure Reducing Valve

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Adjustment
The COSPECT reducing valve should be properly adjusted for protection of the air
equipment.
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 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 COSPECT are completely closed.
3. Remove the spanner cap, loosen the locknut and turn the adjustment screw
counterclockwise to reduce tension on the coil spring.
4. Slowly, fully open the shut-off valve at the inlet of the COSPECT. Allow sufficient
time for condensate remaining at the inlet of the COSPECT to be discharged.
5. Slightly open the shut-off valve at the outlet of the COSPECT.
6. Turn the adjustment screw until the desired outlet pressure is obtained. Wait
several minutes.
7. Slowly, fully open the shut-off valve at the outlet of the COSPECT.
8. After setup, retighten the locknut and replace the cap.
9. When shutting down the system, always close the outlet shut-off valve first and
then the inlet valve.
Loosen the locknut Loosen the adjustment screw
Loosen the Adjustment Screw
Decrease Pressure
Counterclockwise
Clockwise Counterclockwise
Tighten the Adjustment Screw
Increase Pressure

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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 COSPECT, the following inspection and
maintenance should be performed regularly.
Part Inspection and Maintenance Frequency
Screens
(Separator and Pilot)
(For Main Valve and
Pilot Valve Areas)
Disassemble and clean annually.
If there is substantial blockage, install a strainer
(approximately 60 mesh) ahead of the COSPECT.
Main Valve, Main Valve
Seat, Pilot Valve and
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 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 COSPECT 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 COSPECT.
Secure the COSPECT 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 retainer, coil spring and spring
retainer. Check for seizure or any damaged screw threads.
Nameplate
A
djustment
Screw
Locknut
Spring
Housing
Hex
Bolt
Coil Spring
Diaphragm
Support
Ball
Spring Retaine
r
Spanner Cap

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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 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.
Disassembling the Piston
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.
Inspect the interior of the cylinder, the exterior of the piston rings, the small hole on
the piston and the gasket for any fault or abnormality.
Diaphragm
Pilot Valve
S
eat
& Gasket
Pilot Valve
Pilot Valve Spring
Pilot Valve
Body
Notch
Pilot Screen
Pilot
S
creen Holder
& Gasket
Hex Bolt
Gasket
Piston Ring
Tension Ring
Cylinder & Gasket
Gasket
Piston
Connecting Tubes
Hex Bolt
Piston Ring
Tension Ring

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Disassembling the Separator and Main Valve
Turn the COSPECT upside down for easy dismantling of the separator and main
valve. Loosen the hex bolts and remove the trap body. Be careful, as the separator
may drop off when the COSPECT 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 shut-down for a long period, always blow down the piston
section of the body through the plug (option).
Disassembling the Air Trap
Loosen the hex bolts and remove the trap cover. Be careful, as hot condensate may
splash out.
Remove the hex bolts from the trap cover and the float cover to reveal the float.
Remove the float, then loosen the trap valve seat with a box wrench and remove it.
Check to determine that there is no deformation of the float, abnormality in the trap
valve seat or dirt accumulation in the trap cover.
Separator Screen Body
Plug
(option)
Trap Body
Gasket
Hex Bolt
Sleeve
Separato
r
Main Valve Seat & Gasket
Main Valve
Main Valve Spring
Corrugated
Spring Washer
Protective
Bushing
Hex Bolt
Spring Washer
Float Cover
Float
Gasket
Trap Cover
Guide Pin
Hex Bolt
Trap Valve Seat
& Gasket

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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 Ring
Float Cylinder
Trap Valve Seat Separator Screen
Pilot Screen Pilot Valve
Main Valve Seat Pilot Valve Seat
Main Valve and Valve Holder Adjustment Screw
Piston
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
retainer, 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 to tools be
used are as follows:
Part
COSPECT
Connection Size
(mm)
Width Across
Flats (mm)
Tightening Torque
(N⋅m)
Bolts (Spring Housing) All 17 40
Pilot Valve Seat All 19 70
Screen Holder All 24 40
15 – 40 17 60
Bolts
(Pilot Body) 50 19 70
15 – 40 17 60
Bolts
(Trap Cover /Trap Body) 50 19 70
15, 20 36 100
25 41 125
32, 40 60 250
Valve Seat
50 70 300
15, 20 8 7
25 – 40 10 10
Bolts
(Float Cover) 50 13 20
15, 20 11 10
25 – 40 13 15
Trap Valve Seat
50 17 40
1 N⋅m ≈10 kg⋅cm
Caution: If a torque greater than that recommended is applied, the COSPECT or
components may be damaged.
Tension Ring
Assembling the Piston Ring
Ring Gaps
Piston Ring

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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 COSPECT, 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 COSPECT Pressure
Reducing Valve” and “Adjustment” sections be reviewed.
Troubleshooting Chart
Problem Symptom Cause Remedy
No air is being supplied
or the inlet valve is
closed
Check the valves and
piping
The secondary
pressure does
not rise
The pressure
does not increase
The entrance to the
screens or strainer is
clogged
Clean or blow down
The pilot screen is
clogged
Clean
There is insufficient air
flow
Check the flow, replace
the COSPECT if
necessary
The piston is clogged
with dirt
Clean
Check the piston ring
The piston ring is worn Replace with a new
piston ring
The secondary
pressure
cannot be
adjusted or
increases
abnormally
Adjustment is
difficult, and set
pressure varies
There is a build-up of
dirt on the sliding
surfaces of the pilot,
piston or main valve
Clean
Troubleshooting continued on next page

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Troubleshooting Chart (continued)
Problem Symptom Cause Remedy
The adjustment screw
has seized
Replace with a new
adjustment screw
The small hole on the
piston is clogged
Clean
The diaphragm is
distorted or damaged
Replace with a new
diaphragm
There is fluctuation in
air consumption
Check the flow rate,
replace the COSPECT if
necessary
Adjustment is
difficult, and set
pressure varies
The selected model is
inappropriate for the
service conditions
(specifications)
Check the model
selection, replace the
COSPECT if necessary
The bypass valve is
leaking
Check, clean, and
replace with a new valve
if necessary
The secondary
pressure
cannot be
adjusted or
increases
abnormally
(continued)
Upon closing the
valves on the
secondary side,
the secondary
pressure abruptly
rises as high as
the primary
pressure
There is a build-up of
dirt on or damage to
the pilot valve seat or
main valve seat
Clean
Align
Replace if necessary
Occurs at low air
demand
It is being operated
below the lower flow
rate limit
Check the volume of air
supply, replace with a
smaller diameter valve
There is too high a
reduction ratio
Change to an
acceptable operating
range
Hunting never
stops
The selected model is
inappropriate for the
service conditions
(specifications)
Check the model
selection, replace the
COSPECT if necessary
Condensate is
contained, or the trap is
blocked
Check the trap
Check the piping
Hunting or
chattering
occurs
Chattering never
stops
The selected model is
inappropriate for the
service conditions
(specifications)
Check the model
selection, replace the
COSPECT if necessary
Troubleshooting continued on next page