SMC Networks VQC4000 User manual

Doc. No.VQC4000V-OMX0001
Solenoid Valve
PRODUCT NAME
VQC4000Series
(Pilot Valve:V100)
MODEL / Series / Product Number

No.VQC4000V-OMX0001
Contents
Safety Instructions ----------------------------------------------------------------------------2,3
Design / Selection ---------------------------------------------------------------------------- 4 to 6
Mounting ---------------------------------------------------------------------------------------- 6
Piping -------------------------------------------------------------------------------------------- 6
Wiring -------------------------------------------------------------------------------------------- 7
Lubrication -------------------------------------------------------------------------------------- 7
Air Supply --------------------------------------------------------------------------------------- 7
Operating Environment ---------------------------------------------------------------------- 8
Maintenance ------------------------------------------------------------------------------------ 8
Specific Product Precautions --------------------------------------------------------------- 9,10
Manifold option / Assembly Part No.--------------------------------------------------------- 11
Construction ------------------------------------------------------------------------------------- 12
List of valves,options,and Mounting Bolts-------------------------------------------------- 13
Electrical Wiring Specifications---------------------------------------------------------------- 14 to 18
F kit --------------------------------------------------------------------------------------- 14
P kit --------------------------------------------------------------------------------------- 15
T kit --------------------------------------------------------------------------------------- 16
L kit --------------------------------------------------------------------------------------- 17
M kit --------------------------------------------------------------------------------------- 18
Trouble shooting -------------------------------------------------------------------------------19,20
-1-

No.VQC4000V-OMX0001
Safety Instructions
These safety instructions are intended to prevent hazardous situations and/or equipment damage.
These instructions indicate the level of potential hazard with the labels of “Caution,” “Warning” or “Danger.”
They are all important notes for safety and must be followed in addition to International Standards
(ISO/IEC)*1) , and other safety regulations.
*1) ISO 4414: Pneumatic fluid power -- General rules relating to systems.
ISO 4413: Hydraulic fluid power -- General rules relating to systems.
IEC 60204-1: Safety of machinery -- Electrical equipment of machines .(Part 1: General requirements)
ISO 10218: Manipulating industrial robots -Safety.
etc.
Caution
Caution indicates a hazard with a low level of risk which, if not avoided, could result
in minor or moderate injury.
Warning
Warning
indicates a hazard with a medium level of risk which, if not avoided, could
result in death or serious injury.
Danger
Danger
indicates a hazard with a high level of risk which, if not avoided, will result
in death or serious injury.
Warning
1. The compatibility of the product is the responsibility of the person who designs the equipment or
decides its specifications.
Since the product specified here is used under various operating conditions, its compatibility with specific
equipment must be decided by the person who designs the equipment or decides its specifications based on
necessary analysis and test results.
The expected performance and safety assurance of the equipment will be the responsibility of the person who
has determined its compatibility with the product.
This person should also continuously review all specifications of the product referring to its latest catalog
information, with a view to giving due consideration to any possibility of equipment failure when configuring the
equipment.
2. Only personnel with appropriate training should operate machinery and equipment.
The product specified here may become unsafe if handled incorrectly.
The assembly, operation and maintenance of machines or equipment including our products must be
performed by an operator who is appropriately trained and experienced.
3. Do not service or attempt to remove product and machinery/equipment until safety is confirmed.
1.The inspection and maintenance of machinery/equipment should only be performed after measures to
prevent falling or runaway of the driven objects have been confirmed.
2.When the product is to be removed, confirm that the safety measures as mentioned above are implemented
and the power from any appropriate source is cut, and read and understand the specific product precautions
of all relevant products carefully.
3. Before machinery/equipment is restarted, take measures to prevent unexpected operation and malfunction.
4. Contact SMC beforehand and take special consideration of safety measures if the product is to
be used in any of the following conditions.
1. Conditions and environments outside of the given specifications, or use outdoors or in a place exposed to
direct sunlight.
2. Installation on equipment in conjunction with atomic energy, railways, air navigation, space, shipping,
vehicles, military, medical treatment, combustion and recreation, or equipment in contact with food and
beverages, emergency stop circuits, clutch and brake circuits in press applications, safety equipment or
other applications unsuitable for the standard specifications described in the product catalog.
3. An application which could have negative effects on people, property, or animals requiring special safety
analysis.
4.Use in an interlock circuit, which requires the provision of double interlock for possible failure by using a
mechanical protective function, and periodical checks to confirm proper operation.
-2-

No.VQC4000V-OMX0001
Safety Instructions
Caution
The product is provided for use in manufacturing industries.
The product herein described is basically provided for peaceful use in manufacturing industries.
If considering using the product in other industries, consult SMC
beforehand and exchange
specifications or a contract if necessary.
If anything is unclear, contact your nearest sales branch.
Limited warranty and Disclaimer/Compliance Requirements
The product used is subject to the following “Limited warranty and Disclaimer” and “Compliance
Requirements”.
Read and accept them before using the product.
Limited warranty and Disclaimer
1.The warranty period of the product is 1 year in service or 1.5 years after the product is
delivered,whichever is first.
∗
2)
Also, the product may have specified durability, running distance or replacement parts. Please
consult your nearest sales branch.
2. For any failure or damage reported within the warranty period which is clearly our responsibility,
a replacement product or necessary parts will be provided.
This limited warranty applies only to our product independently, and not to any other damage
incurred due to the failure of the product.
3. Prior to using SMC products, please read and understand the warranty terms and disclaimers
noted in the specified catalog for the particular products.
∗
2) Vacuum pads are excluded from this 1 year warranty.
A vacuum pad is a consumable part, so it is warranted for a year after it is delivered.
Also, even within the warranty period, the wear of a product due to the use of the vacuum
pad or failure due to the deterioration of rubber material are not covered by the limited
warranty.
Compliance Requirements
1.
The use of SMC products with production equipment for the manufacture of weapons of mass
destruction(WMD) or any other weapon is strictly prohibited.
2. The exports of SMC products or technology from one country to another are governed by the
relevant
security laws and regulation of the countries involved in the transaction. Prior to the
shipment of a SMC product to another country, assure that all local rules governing that export
are known and f
ollowed.
Caution
SMC products are not intended for use as instruments for legal metrology.
Measurement instruments that SMC manufactures or sells have not been qualified by type approval tests
relevant to the metrology (measurement) laws of each country.
Therefore, SMC products cannot be used for business or certification ordained
by the metrology
(measurement) laws of each country.
-3-

- 4 -
No.VQC4000V-OMX0001
Design / Selection
1. Confirm the specifications
Products represented in this catalog are designed only
for use in compressed air systems (including vacuum).
Do not operate at pressures or temperatures, etc.,
beyond the range of specifications, as this can cause
damage or malfunction. (Refer to the specifications.)
Please contact SMC when using a fluid other than
compressed air (including vacuum).
We do not guarantee against any damage if the
product is used outside of the specification range.
2. Actuator drive
When an actuator, such as a cylinder, is to be driven
using a valve, take appropriate measures (cover
installation or approach prohibition) to prevent potential
danger caused by actuator operation.
3. Intermediate stops
For 3-position closed center or double check valve type,
it is difficult to make a piston stop at the required
position accurately due to the compressibility of air.
Furthermore, since valves and cylinders are not
guaranteed for zero air leakage, it may not be possible
to hold a stopped position for an extended period of
time. Please contact SMC if it is necessary to hold a
stopped position for an extended period of time.
4. Effect of back pressure when using a
manifold.
Use caution when valves are used on a manifold,
because an actuator may malfunction due to
back-pressure. For 3-position exhaust center valve of
single acting cylinder, take appropriate measures to
prevent the malfunction by using it with an individual
exhaust spacer.
5. Holding pressure (including vacuum).
Since the valve are subject to air leakage, they cannot
be used for applications such as holding pressure
(including vacuum) in a pressure vessel.
6. Not suitable for use as an emergency
shut-off valve, etc.
The valves listed in this instruction manual are not
designed for safety applications such as an emergency
shutoff valve. If the valves are used for the mentioned
applications, additional safety measures should be
adopted.
7. Release of residual pressure
For maintenance purposes install a system for
releasing residual pressure. Especially in the case of
3-position closed center valve or double check valve
type, ensure that the residual pressure between the
valve and the cylinder is released.
8. Operation in a vacuum condition
When a valve is used for switching a vacuum, take
measures to install a suction filter or similar to prevent
external dust or other foreign matter from entering
inside the valve. In addition, at the time of vacuum
adsorption, be sure to supply a constant supply of
vacuum. Failure to do so may result in foreign matter
sticking to the adsorption pad or air leakage, causing
the workpiece to drop.
9. Regarding vacuum switch valves and
vacuum release valves
If a non-vacuum valve is installed in the middle of a
piping system that contains a vacuum, the vacuum
condition will not be maintained. Use a valve designed
for use under vacuum conditions.
10. Double solenoid type
When using the double solenoid type for the first time,
actuators may travel in an unexpected direction
depending on the switching position of the valve.
Implement measures to prevent any danger from
occurring when operating the actuator.
11. Ventilation
Provide ventilation when using a valve in a confined
area, such as in a closed control panel. For example,
install a ventilation opening, etc. in order to prevent
pressure from increasing inside of the confined area
and to release the heat generated by the valve.
12. Extended periods of continuous
energization
･If a valve will be continuously energized for an
extended period of time, the temperature of the valve
will increase due to the heat generated by the coil.
This will likely adversely affect the performance of the
solenoid valve and any nearby peripheral equipment.
Therefore, when it is continuously energized or the
energized period per day is longer than the
de-energized period use either: DC specification,
power-saving type. Also, please contact SMC
because depending on the application, there may be
additional valves not mentioned above that may be
used.
･For applications such as mounting a valve on a
control panel, incorporate measure to limit the heat
radiation so that it is within the operation temperature
range. For example, the temperature will be high
when a 3 station manifold.
13. Do not disassemble the product of
make any modifications, including
additional machining.
It may cause human injury and/or an accident.
14. Resumption after a long period of
holding time
When resuming operation after a long period of
holding time, there are cases in which, regardless of
whether the product is in an ON or OFF state, there is
a delay in the initial response time due to adhesion.
Conducting several cycles of running-in operation will
solve this problem. Please consider implementing this
before resumption.
Warning
Be sure to read before handling. Refer to main text for detailed precautions on every series.
VQC4000 Series
Precautions for 5 Port Solenoid Valve 1

- 5 -
No.VQC4000V-OMX0001
Design / Selection
1. Precautions on 2-position double
solenoid valve
If a double solenoid valve is operated with momentary
energization, it should be energized for at least 0.1
second. However, depending on the piping conditions,
cylinder may malfunction even when the double
solenoid valve is energized for 0.1 second or longer. In
this case, energize the double solenoid valve until the
cylinder is exhausted completely.
2. Leakage voltage
Take note that the leakage voltage will increase when a
resistor is used in parallel with switching element or a
C-R circuit (surge voltage suppressor) is used for
protecting a switching device because of the passing
leakage voltage through the C-R circuit.
The suppressor residual leakage voltage should be as
follows. Should be 3% or less of rated voltage.
3. Surge voltage suppressor
1) A surge voltage suppressor built into the valve is
intended to protect the output contacts so that the
surge generated inside valve does not adversely
affect the output contacts. Therefore, if an
overvoltage or overcurrent is received from an
external peripheral device, the surge voltage
protection element inside the valve is overloaded,
causing the element to break. In the worst case, the
electric circuit enters the short-circuit status by the
breakage. If the energizing continues in this status,
a large current flows. This may cause secondary
damage to the output circuit, external peripheral
device, or valve, and may also cause fire accident.
So, take appropriate protective measures, such as
installation of an overcurrent protection circuit in the
power supply or drive circuit to maintain the
sufficient safety.
2) If a surge protection circuit contains nonstandard
diodes, such as Zener diodes or varistor, a residual
voltage that is in proportion to the protective circuit
and the rated voltage will remain. Therefore, take
into consideration the surge voltage protection of
the controller.In the case of diodes, the residual
voltage is approximately 1 V.
4. Surge voltage intrusion
With non-polar type solenoid valves, at times of
sudden interruption of the loading power supply, such
as emergency shutdown, surge voltage intrusion may
be generated from loading equipment with a large
capacity (power consumption), and the solenoid
valve in a deenergized state may switch over (see
Figure 1).
When installing a breaker circuit for the loading
power supply, consider using a solenoid valve with
polarity (with polarity protection diode), or install a
surge absorption diode between the loading
equipment COM line and the output equipment COM
line (see Figure 2).
Caution
VQC4000 Series
Precautions for 5 Port Solenoid Valve 2
Be sure to read before handling. Refer to main text for detailed precautions on every series.

- 6 -
No.VQC4000V-OMX0001
Design / Selection
5. Operation in a low temperature
condition
It is possible to operate a valve in extreme
temperature, as low as -10 oC. Take appropriate
measures to avoid freezing of drainage, moisture etc.
in low temperature.
6. Operation for air blowing
When using a solenoid valve for air blowing, use an
external pilot type. Use caution because the pressure
drop caused by the air blowing can have an affect on
the internal pilot type valve when the internal pilot type
valves and external pilot type valves are used on the
same manifold.
Additionally, when compressed air within the pressure
range of the established specifications is supplied to
the external pilot type valve’s port, and a double
solenoid valve is used for air blowing, the solenoids
should normally be energized when air is being
blown.
7. Mounting orientation
Rubber seal : Mounting orientation is free.
Metal seal : Mounting orientation of a single solenoid
is universal.No specific orientation is
necessary. When installing a double
solenoid or a 3-position configuration,
mount the valve so that spool valve is
horizontal.
8. Initial lubrication of main valve
The following initial lubricant has already been applied
to the main valve.
Rubber seal, spool valve: Grease Please consult
with SMC, as there are some standard valve
products that use fluorine grease for food
processing equipment (NSF H-1).
Metal seal, spool valve: Turbine oil
Turbine oil is applied to the spool valve of a metal
seal type. Therefore, turbine oil may seep out when
a new product is delivered, or while the valve is
stored.
9. For the pilot EXH(PE) port
If the solenoid valve and the manifold’s pilot EXH (PE)
port is restricted extremely or blocked, abnormal
operation of the solenoid valve may occur.
Mounting
1. Operation manual
Install the products and operate them only after
reading the operation manual carefully and
understanding its contents. Also, keep the manual
where it can be referred to as necessary.
2. Ensure sufficient space for maintenance
activities.
When installing the products, allow access for
maintenance.
3. Tighten threads with the proper
tightening torque.
When installing the products, follow the listed torque
specifications.
4. If air leakage increases or equipment
does not operated properly, stop
operation.
Check mounting conditions when air and power
supplies are connected. Initial function and leakage
tests should be performed after installation.
5. Painting and coating
Warnings or specifications printed or affixed to the
product should not be erased, removed or covered up.
Please consult with SMC before applying paint to
resinous parts, as this may have an adverse effect due
to the solvent in the paint.
Piping
1. Refer to the Fittings and Tubing
Precautions for handling one-touch
fittings.
2. Preparation before piping
Before piping is connected, it should be thoroughly
blown out with air (flushing) or washed to remove chips,
cutting oil and other debris from inside the pipe.
3. Wrapping of pipe tape
When screwing piping or fittings into ports,
ensure that chips from the pipe threads
or sealing material do not enter the piping.
Also, if pipe tape is used,
leave 1 thread ridges exposed
at the end of the threads.
4. Closed center and double
check valve types
For closed center or double check valve types,
check the piping to prevent air leakage from the
piping between the valve and the cylinder.
5. Connection of piping and fittings
When screwing piping or fittings into the valves,
tighten them as follows.
Excessive tightening may damage the thread portion
or deform the gasket and cause air leakage.
Insufficient tightening may loosen the threads or
cause air leakage.
When using a fitting other than an SMC fitting, follow
the instructions given by the fitting manufacturer.
For the tightening torque, refer to the table below.
Connection thread
size (Rc)
Proper tightening torque
(N
･
m)
1/8
3 to 5
1/4
8 to 12
3/8
15 to 20
1/2
20 to 25
6. Piping to products
When piping to a product, refer to the operation
manual to avoid mistakes regarding the supply port,
etc.
Warning
Caution
Caution
VQC4000 Series
Precautions for 5 Port Solenoid Valve 3
Be sure to read before handling. Refer to main text for detailed precautions on every series.

- 7 -
No.VQC4000V-OMX0001
Wiring
1. The solenoid valve is an electrical
product. For safety, install an appropriate
fuse and circuit breaker before use.
1. Applied voltage
When electric power is connected to a solenoid valve,
be careful to apply the proper voltage. Improper
voltage may cause malfunction or coil damage.
2. Check the connections
Check if the connections are correct after completing
all wiring.
3. External force applied to the lead wire
If an excessive force is applied to the lead wire, this
may cause faulty wiring. Take appropriate measures
so that a force of 30 N or more is not applied to the
lead wire. When instructions are given in the Specific
Product Precautions, follow these specifications.
Lubrication
1. Lubrication
[Rubber seal]
1) These valves can be used without lubrication.
2) If a lubricant is used in the system, use class 1
turbine oil (no additive), ISO VG32. For details about
lubricant manufacturers’ brands, refer to SMC
website.
Additionally, please contact SMC for details about
class 2 turbine oil (with additives) ISO VG32. Once
lubricant is utilized within the system, since the
original lubricant applied within the product during
manufacturing will be washed away, please continue
to supply lubrication to the system. Without continued
lubrication, malfunctions could occur.
If turbine oil is used, refer to the Safety Data Sheet
(SDS) of the oil.
[Metal seal]
1) These valves can be used without lubrication.
2) If a lubricant is used in the system, use class 1
turbine oil (no additive), ISO VG32. For details
about lubricant manufacturers’ brands, refer to SMC
website.
Additionally, please contact SMC for details about
class 2 turbine oil (with additives) ISO VG32.
2. Lubrication amount
If the lubrication amount is excessive, the oil may
accumulate inside the pilot valve, causing malfunction
or response delay. So, do not apply a large amount of
oil. When a large amount of oil needs to be applied,
use an external pilot type to put the supply air on the
pilot valve side in the non-lube state. This prevents
accumulation of oil inside the pilot valve.
Air Supply
1. Type of fluids
Please consult with SMC when using the product in
applications other than compressed air.
2. When there is a large amount of drainage.
Compressed air containing a large amount of drainage
can cause the malfunction of pneumatic equipment. An
air dryer or water separator should be installed
upstream from filters.
3. Drain flushing
If condensation in the drain bowl is not emptied on a
regular basis, the bowl will overflow and allow the
condensation to enter the compressed air lines. It
causes malfunction of pneumatic equipment. If the
drain bowl is difficult to check and remove, installation
of a drain bowl with an auto drain option is
recommended.
For compressed air quality, refer to SMC’s Best
Pneumatics catalog.
4. Use clean air
Do not use compressed air that contains chemicals,
synthetic oils including organic solvents, salt or
corrosive gasses, etc., as it can cause damage or
malfunction.
1. When extremely dry air is used as the fluid,
degradation of the lubrication properties
inside the equipment may occur, resulting
in reduced reliability (or reduced service
life) of the equipment. Please consult with
SMC.
2. Install an air filter.
Install an air filter upstream near the valve. Select an
air filter with a filtration size of 5 μm or smaller.
3. Take measures to ensure air quality, such
as by installing an aftercooler, air dryer, or
water separator.
Compressed air that contains a large amount of
drainage can cause the malfunction of pneumatic
equipment, such as valves. Therefore, take
appropriate measures to ensure air quality, such as by
providing an aftercooler, air dryer, or water separator.
4. If an excessive amount of carbon powder
is present, install a mist separator on the
upstream side of the valve.
If excessive carbon dust is generated by the
compressor, it may adhere to the inside of a valve and
cause it to malfunction.
For compressed air quality, refer to SMC’s Best
Pneumatics catalog.
Warning
Caution
Warning
VQC4000 Series
Precautions for 5 Port Solenoid Valve 4
Be sure to read before handling. Refer to main text for detailed precautions on every series.
Warning
Caution

- 8 -
No.VQC4000V-OMX0001
Operating Environment
1. Do not use in an atmosphere having corrosive
gases, chemicals, sea water, water, water steam, or
where there is direct contact with any of these .
2. Products with IP65 and IP67 enclosures (based on
IEC60529) are protected against dust and water.
However, these products cannot be used in water.
however, these products cannot be used in water.
3. Products compliant with IP65 and IP67 satisfy the
product specifications when mounted properly. Be
sure to read the precautions for each product.
4. Do not use in an environment where flammable
gas or explosive gas exists. Usage may cause a
fire or explosion. The products do not have an
explosion proof construction.
5. Do not use in a place subject to heavy vibration
and/or shock.
6. The valve should not be exposed to prolonged
sunlight. Use a protective cover. Note that the
valve is not for outdoor use.
7. Remove any sources of excessive heat.
8. If it is used in an environment where there is
possible contact with oil, weld spatter, etc.,
exercise preventive measures.
9. When the solenoid valve is mounted in a control
panel or it’s energized for a long period of time,
make sure the ambient temperature is within the
specifications of the valve.
1. Temperature of ambient environment
Use the valve within the range of the ambient
temperature specification of each valve. In addition,
pay attention when using the valve in environments
where the temperature changes drastically.
2. Humidity of ambient environment
When using the valve in environments with low
humidity, take measures to prevent static.
If the humidity rises, take measures to prevent the
adhesion of water droplets on the valve.
Maintenance
1. Perform maintenance inspection
according to the procedures indicated in
the operation manual.
If handled improperly, human injury and/or
malfunction or damage of machinery and equipment
may occur.
2. Removal of equipment, and
supply/exhaust of compressed air
Before components are removed, first confirm that
measures are in place to prevent workpieces from
dropping, run-away equipment, etc. Then, cut off the
supply air and electric power, and exhaust all air
pressure from the system using the residual pressure
release function.
For 3-position closed center type, exhaust the
residual pressure between the valve and the actuator.
When the equipment is operated after remounting or
replacement, first confirm that measures are in place
to prevent lurching of actuators, etc. Then, confirm
that the equipment is operating normally.
In particular, when a 2-position double solenoid valve
is used, releasing residual pressure rapidly may
cause the spool valve to malfunction, depending on
the piping conditions, or the connected actuator to
operate.
3. Low frequency operation
Valves should be operated at least once every 30
days to prevent malfunction. (Use caution regarding
the air supply.)
4. Manual override
When a manual override is operated, connected
equipment will be actuated. Operate only after safety
is confirmed.
5. If the volume of air leakage increases or
the valve does not operate normally, do
not use the valve. Perform periodic
maintenance on the valve to confirm the
operating condition and check for any air
leakage.
1. Drain flushing
Remove drainage from the air filters regularly.
2. Lubrication
In the case of rubber seals, once lubrication has been
started, it must be continued.
Use class 1 turbine oil (with no additives), VG32. If
other lubricant oil is used, it may cause a malfunction.
Please contact SMC for information on the suggested
class 2 turbine oil (with additives), VG32.
3. Manual override operation
When switching a double solenoid valve via the
manual override operation, instantaneous operation
may cause the malfunction of the cylinder. It is
recommended that the manual override be held until
the cylinder reaches the stroke end position.
Warning Warning
Caution
Caution
VQC4000 Series
Precautions for 5 Port Solenoid Valve 5
Be sure to read before handling. Refer to main text for detailed precautions on every series.

- 9 -
VQC4000V-OMX0001
Continuous Duty
When the product is continuously energized for a long
period of time (10 minutes or longer), select the low
wattage type (DC specification).
Manual Override
Since connected equipment will operate when the
manual override is activated, confirm that
conditions are safe prior to activation.
Push type(Tool required)
Push down the manual
override button
with a small screwdriver, etc.,
until it stops. The manual override
will return when released.
Locking type (Tool required)
Push down the manual
override button with a small flat head screwdriver
until it stops, and turn it clockwise 90°
to lock it. Turn it counterclockwise
to release it.
Locking type (Manual)
Push down the manual override button with a small flat
head screwdriver or with your finger until it stops, and
turn it clockwise 90° to lock it. Turn it counterclockwise
to release it.
Do not apply excessive torque when turning the manual
override. [0.1 N·m or less]
Valve Mounting
After confirming that the gasket is installed correctly,
securely tighten the mounting screws according to
the tightening torque shown below.
Replacement of One-touch Fittings
Cylinder port fittings are available in cassette type
and can be replaced easily. Fittings are secured with a
retaining clip that is inserted from the top side of the
valve. After removing the valve, remove the clip with a
flat head screwdriver to replace the fittings. To mount
a fitting, insert the fitting assembly until it stops and
reinsert the retaining clip to its designated position.
Lead Wire Connection
Plug-in sub-plate (With terminal block)
VQC4000 Series
Specific Product Precautions 1
Be sure to read before handling. Refer to main text
for detailed precautions on every series.

- 10 -
VQC4000V-OMX0001
Installation and Removal of Light Cover
• Removal
Open the cover by inserting a small flat head screwdriver
into the slot on the side of the pilot assembly (see drawing
below), lift the cover out about 1 mm and then pull off. If it
is pulled off at an angle, the pilot valve may be damaged
or the protective Oring may be scratched.
• Installation
Place the cover straight over the pilot assembly so that
the pilot valve is not touched, and push it until the cover
hook locks without twisting the protective O-ring. (When
pushed in, the hook opens and locks automatically.)
Replacement of Pilot Valve
• Removal
Remove the mounting screw
that holds the pilot valve
using a small screwdriver.
• Installation
After confirming the gasket is
correctly placed under the
valve, securely tighten
the bolts
with the proper torque
shown in the table below.
Internal Wiring Specifications
How to Calculate the Flow Rate
For obtaining the flow rate, refer to the WEB catalog or
the Best Pneumatics No. 1.
VQC4000 Series
Specific Product Precautions 2
Be sure to read before handling. Refer to main text for detailed precautions on every series.

- 11 -
VQC4000V-OMX0001
Manifold Options
Manifold Assembly Part No.

- 12 -
VQC4000V-OMX0001
Construction

- 13 -
VQC4000V-OMX0001
List of Valves, Options, and
Mounting Bolts

- 14 -
VQC4000V-OMX0001

- 15 -
VQC4000V-OMX0001

- 16 -
VQC4000V-OMX0001

- 17 -
VQC4000V-OMX0001

- 18 -
VQC4000V-OMX0001

- 19 -
No.VQC4000V-OMX0001
Trouble
When the valve is failing, use this flow chart to
clarify the cause of the failure and take
countermeasures appropriate for the cause.
Possible cause Countermeasures
Operating
failure
The air
supply
does not
switch the
valve.
1) Sliding failure or stick of
main valve.
A foreign material included in
supplied air is caught by main
valve and makes the main
valv
e unable to slide smoothly
or sticky.
•Replace with new valve.
•Clean the supplied air.
2) Pressure drop.
The pressure of suppli
ed air
lowers the valve which can
operate the valve (min.
operating pressure).
Raise the pressure of supplied air up
to operating pressure of the valve.
1) Failure of electrical system
•Incorrect wiring
•Blow of fuse and breakage of
lead wire.
•Poor contact at contactor wire
or connection part
•Failure of sequencer
•Lack of supply voltage
Check these items and replace part
and re-wire positively.
1) Voltage drop
Even if the indicator light keeps
turning on, the valve can’t be
operated due to the voltage
drop.
•Check the voltage and if it is not
enough to operate the valve, take
appropriate measures.
2) Leakage current
When the power turns off, the
valve can’t be switched due to
residual voltage.
•Confirm the residual voltage is
follows.
•DC is 3% or less of rated voltage.
3) Failure of pilot valve
•Foreign matter caught in
core of pilot valve.
•Disconnection coil
wire of pilot valve
•Swelled out poppet
of pilot valve
•Burnt coil of pilot valve
(Higher voltage or wrong coil
used, Coil splashed by
water)
•Replace part or re-wire positively.
•Check voltage. Replace valve.
(Pilot valve)
•
Replace valve (pilot valve). Protect
the valve so that water does not
splash the coil.
Response
failure
The
operation
of the valve
is delay.
1) Current leakage
When the power turns off, the
valve can be switched late due
to residual voltage.
•Confirm the residual voltage is
follows.
•DC is 3% or less of rated voltage.
2) Clogging of filter element of
manifold.
•Clean the element or replace with
new element.
3) Sliding failure or stick of
main valve.
A foreign material included in
supplied air is caught by main
valve and makes the main
valve unable to slide smoothly
or sticky.
•Replace with new valve.
•Clean the supplied air.
Can manual
override move the
valve
NO
YES
Does the indicator
light keep turning on
during
energization?
NO
YES