YAMADA NDP-25 series User manual

Doc. No. NDP431U-00
OPERATION MANUAL
YAMADA AIR-OPERATED DIAPHRAGM PUMPS
(for powder material)
NDP-25 series
NDP-40 series
NDP-50 series
NDP-80 series

1
- Introduction
Thank you for purchasing a Yamada Diaphragm Pump. This product is a positive-displacement pump
that transfers materials by movement of diaphragms driven by compressed air through a unique
switching mechanism. The casing that comes in contact with the material is made of aluminum, stainless
steel depending on the model you have selected according to the type of material to be pumped. The
diaphragms are made of a thermoplastic elastomer material suitable for the Application.
- For safe operation
This document contains information vital for safe and efficient operation of this product. Before using the
pump, be sure to read this document carefully, particularly the "warnings and cautions", and be fully
familiar with the operating procedures. Be sure to keep this document handy for future reference.

2
- Warnings and cautions
For safe use of this product, be sure to NOTE the following: In this document, warnings and cautions are
indicated by symbols. These symbols are for those who will operate this product and for those who will be
nearby, for safe operation and for prevention of personal injury and property damage.
The following warning and caution symbols have the meanings described below. Be sure to remember
their meanings.
WARNING:This indicates the existence of potential hazard which, if not avoided,
will result in death or serious injury.
CAUTION : This indicates the existence of potential hazard which, if not avoided,
may result in bodily injury or in physical damage.
To indicate the contents of danger and damage, the following symbols are used together with the above
indications.
This symbol indicates an act that is prohibited (prohibition). The concrete contents of
prohibition are indicated by the side of the indication.
This symbol indicates the contents that must be observed. The concrete contents of
observance are indicated by the side of the indication.
- Operating caution
Before using this product
WARNING
- When using compressed gas (hereinafter called "compressed air") to drive this pump, be
sure it is one of the following:
* Compressed air supplied from an air compressor
* Nitrogen (N2) gas
Use of compressed air other than the above may cause air pollution, damage to the pump,
or even an explosion.
- The maximum allowable operating pressure for compressed air and powder material being
pumped is shown in [9.1 Main specifications] as Operating Air Pressure.
Use of compressed air or powder material which exceeds the operating air pressure can
cause material leaks, damage to the pump casings and diaphragms, or even fatal accidents.
- When moving this product, make sure that the internal pressure is released. If the pump is
moved while under pressure, any shock imparted by droppage, etc. may damage the pump
or even cause an explosion.
- Hazardous material (strongly-acid or -alkaline, flammable, or toxic) and its atmosphere
may cause serious injury or even death if it comes in contact with your eyes or skin or if it
is inhaled or ingested. Therefore, the following precautions are strongly advised.
*Be fully familiar with the properties of the material to be pumped and work in strict
accordance with the operating instructions provided by the suppliers of such materials
(such as wearing goggles, gloves, mask or work clothes).
*When storing a hazardous material, strictly comply with the regulatory procedures
(such as using proper containers, storage conditions, etc.).
*Always install the piping and exhaust port of this pump away from human and animal
traffic.
- When a diaphragm is damaged, material will gush out together with air through the
exhaust port. Also when pump has positive suction head, material will be forced out from
exhaust port due to positive inlet pressure. Make sure to provide protective measures in
consideration of possible leakage of material (see ＜NOTE＞Arranging outside exhaust on
P.9). For example using a hose and pit etc., also be sure you are using a model with
appropriate corrosion resistance for the material to be pumped.

3
WARNING
- When installing this product, be sure to connect a ground wire from the specified position of
this product. When this product is installed and operated without the ground wire properly
connected, friction between parts, as well as abrasion caused by the flow of some materials
inside the casing, may generate static electricity. Also, depending on the type of material
being pumped and the installation environment (such as gases in the air and type of
surrounding fixtures), static electricity could become a cause of fire or electric shock.
- Improper grounding, poor ventilation, or unshielded fire or spark can create a danger of fire
or explosion. Therefore, the following precautions are strongly advised.
*All peripheral equipment and piping connected to this product should be properly
grounded.
*Whenever you notice any spark while operating this product, immediately stop its
operation, and do NOT start using it again unless you are sure of the cause and corrective
actions have been taken.
*Depending upon the type of material being pumped, bubbles of flammable gas may be
generated. Make sure that ventilation is satisfactory.
*This product itself, its piping and exhaust ports should be kept away from unshielded fire,
spark and other causes of ignition. If a diaphragm is damaged, material will gush out
together with air from the exhaust port.
*Do NOT leave gasoline or solvent etc. that contains waste at the work site.
*Machinery and other equipment near the place of installation of this product should be
properly insulated to prevent conduction with each other.
*Do NOT operate heating devices that create flames or have heating filaments anywhere
near the pump or its piping.
*If there are flammable gases in the air while the pump is operating, do NOT switch
electric appliance on and off.
*Do NOT operate a gasoline engine at the work site.
*Restrict smoking at the work site.
- Remove residual material from the pump and piping before disconnecting or storing. Even
when not in operation, the pump and piping may contain residual material inside. Also, if
the pump is not in use for a long period of time, residual material may stick to the inside of
the pump and piping, resulting in damage to the pump or material leaks when the pump is
restarted.
- Always use genuine Yamada parts when replacing component parts of this product. Do NOT
attempt to modify the components parts or replace them with other than genuine Yamada
parts.
- Torque of all tightening parts must be inspected before operation. Designated torque are
mentioned in maintenance manual.

4
WARNING
- When pumping a hazardous material (hot, flammable, strong acid, etc.) with this product,
provide protective measures (install a pit, a protection box, sensors, etc.) in consideration of
possible leakage of material, and post warning signs at necessary places.
Make the warning symbols in [12.Warning symbols], and attach them to the casing and
piping, etc.
Leakage of material may cause fire,
air pollution or a serious accident.
When pumping a hot material, the
casing and piping will become hot,
which may burn the skin when
touched.
- Before use, be sure you are familiar with the precautions regarding the powder material to
be pumped and verify the material compatibility for the pump parts that will come into
contact with the powder material. NEVER use the pump with any powder material which is
not compatible with the pump parts or poses a risk of explosion. If you are unsure of the
material compatibility for the pump parts, contact your dealer or our regional office.
Use of the powder material which is not compatible with the materials used in the pump
parts may result in damage to the pump or material leaks.
- When working in the vicinity of pumping of material with this product, be sure to wear
protective gear (goggles, mask, etc.).
- When using this product, observe the relevant regulatory rules concerning fire prevention,
labor safety standards, etc.
- If you have any questions on the operation of this product (method of connection or
installation), contact your dealer or our regional office.
CAUTION
- When operating this product, it may generate loud operating noise, depending upon the
condition of use (material pumped, supply air pressure and discharge pressure). If
regulatory rules apply, provide appropriate acoustic measures where necessary. (For the
noise value of this product, see [9.1 Main specifications].)
- To drive this product, use supply air with minimum moisture content.
- If a diaphragm is damaged, the powder material may be exposed to supply air or flow into
the main body. Considering this, do not use the pump if the powder material can be affected
by supply air or air dust or if the powder material is incompatible with the material use in
the main body.
- While operating this product, do NOT cover the intake port by hand.
- If the pump remains unused for a long period of time, or you have misgivings about running
the pump, please consult with the dealer where you purchased it or our Sales office.
Fig.0.1

5
Table of Contents
- Introduction ·············································································· 1
- For safe operation ······································································ 1
- Warnings and cautions································································ 2
- Operating caution ······································································ 2
- Table of Contents ······································································· 5
1. Names of parts and materials
1.1 NDP-25 series ···································································· 6
1.2 NDP-40, 50, 80 series ·························································· 7
2. Installation
2.1 Method of transport ···························································· 8
2.2 Installing the pump ···························································· 8
2.3 Connecting the ground wire·················································10
3. Connection
3.1 Connecting material piping ·················································11
3.2 Connecting air piping ·························································12
4. Operation
4.1 Method of operation ···························································13
4.2 Shutdown·········································································13
5. Method of cleaning ·································································14
6. Daily check ···········································································15
7. Troubleshooting
7.1 Pump does not run ·····························································15
7.2 Pump runs, but material does not come out· ···························15
7.3 Flow (discharge volume) decreased ·······································15
7.4 Material leaks from exhaust port (silencer) ····························16
7.5 High air consumption during in operation ······························16
7.6 Irregular noise ··································································16
7.7 Irregular vibration·····························································16
8. Returning the product for servicing
8.1 How to use the FAX sheet ···················································16
8.2 Before returning the product ···············································16
9. Main body specifications
9.1 Main specifications ····························································17
9.2 Appearance and dimensions·················································17
10. Trouble-Reporting FAX Sheet ····················································20
11. Limited warranty ····································································21
12. Warning symbols·····································································22

6
1. Names of parts and materials
1.1 NDP-25 series
A：Air Valve G：Discharge Port
B：Reset Button H：Intake Port
C：Out Manifold I：Lift Point
D：Out Chamber J：Ground Connection Point
E：In Manifold K：Needle Valve
F：Pump Base
NDP-25BA□, NDP-25BS□
- Aluminum type - Stainless-steel type
Type BAC BAN Type BSC BSN
Switching Portion ADC12 Switching Portion ADC12
Material Contact Portion ADC12 Material Contact Portion SCS14
Diaphragm CR NBR Diaphragm CR NBR
Ball/O Ring CR/NBR NBR Ball/O Ring CR/NBR NBR
Valve Seat SMS1025 Valve Seat SUS316
Center Disk SUS316 Center Disk SUS316
I
C
K
D
A
H
K
E
F
G
K
J
B

7
1.2 NDP-40, 50, 80 series
A：Air Valve G：Discharge Port
B：Reset Button H：Intake Port
C：Out Manifold I：Lift Point
D：Out Chamber J：Ground Connection Point
E：In Manifold K：Needle Valve
F：Pump Base
NDP-40BA□, NDP-40BS□
NDP-50BA□, NDP-50BS□
NDP-80BA□, NDP-80BS□
- Aluminum type - Stainless-steel type
Type BAC BAN Type BSC BSN
Switching Portion ADC12 Switching Portion ADC12
Material Contact Portion ADC12, AC4C-T6 Material Contact Portion SCS14
Diaphragm CR NBR Diaphragm CR NBR
Ball/O Ring CR/NBR NBR Ball/O Ring CR/NBR NBR
Valve Seat CR NBR Valve Seat CR NBR
Center Disk A5056 Center Disk SUS316
I
A
J
B
D
K
E
F
H
G
C
K

8
2. Installation
2.1 Method of transport
When lifting the pump using a chain hoist or crane before transporting it, be sure to lift it by the
specified lift point (see [1. Names of parts and materials]).
WARNING
- Be careful that nobody will pass under the pump when you lift it. It would be very
dangerous if the pump should fall.
CAUTION
- See [9.1 Main specifications]. Remember that the pump is heavy, so extreme care must be
taken when lifting it.
- When moving the pump with a forklift or truck, make sure that the pump will not fall. If it
does, it may be damaged and/or cause bodily injury.
- NEVER try to move the pump by pulling the hose connected to the pump. The hose or the
pump may be damaged.
2.2 Installing the pump
1) Decide where the pump should be installed and secure a suitable space (see Fig. 2.1 A to C).
2) Remove the pump from the package and install it in the designated location.
3) When fixing the pump in place, use the cushions on the pump base, and secure the pump by
tightening the tied-down bolts a little at a time.
Fig2.1

9
WARNING
- If using the pump with a flammable material or in a flammable environment, read the
applicable operating caution on P.3.
CAUTION
- Even if you do not use the cushions to secure the pump in place, mount it in such a way
that vibration generated by pump operation will be absorbed.
- When operating the pump, operation noise may be generated, depending upon conditions of
use (kind of material being pumped, supply air pressure and discharge pressure).
If any regulatory rules apply, provide appropriate acoustic measures. (For the noise level of
this product, see [9.1 Main specifications].)
- When pumping a hazardous material (hot, flammable, strong acid, etc.), provide protective
measures (installation of a pit or sensors, etc.) in consideration of possible leakage of
material, and post warning signs at necessary places. For details, see the applicable
operating caution on P.2 and P.4.
＜NOTE＞Arranging outside exhaust
- Remove the silencer.
- Connect a hose with a ground wire to the pump's exhaust
port, and attach the silencer to the tip of the hose. Use a
hose of the same diameter as the exhaust port. (If the
hose is longer than 5 meters, consult your dealer or our
regional office.)
- Have a pit, a protection box, etc. at the end of the hose.
WARNING
- Be sure to have a pit, a protection box, etc. at the end of the hose in preparation for the flow
of material in case of damage to a diaphragm. For details, see the applicable operating
caution on P.2.
- Pump exhaust should be directed to a safe place, away from people, animals and food.
＜NOTE＞
When air line operation is to be controlled by a solenoid valve, a three way type is recommended.
A three-way solenoid valve allows any trapped air to bleed off, in turn improving pump performance.
Fig2.2

10
2.3 Connecting the ground wire
a) When installing the pump, be sure to connect the ground wire at the specified position. For the
specified position for connecting the ground wire, see [1. Names of parts and materials].
b) Also connect ground wires to peripheral equipment and piping.
c) Use 2.0mm2minimum ground wire.
WARNING
- Be sure to connect ground wires to the connected piping and any other connected
equipment. For details, see the applicable operating caution on P.3.
When the pump is operated without a ground wire or otherwise not properly grounded,
friction between parts and abrasion caused by some fluids flowing inside the casing may
generate static electricity. Also, depending on the type of fluid being pumped and the
installation environment (such as gases in the air or the surrounding fixtures), it may be a
cause of fire or electric shock.
Fig2.3
Position for
connecting
the ground

11
3. Connection
3.1 Connecting fluid piping
1) Connect a hose to the valve on the suction-port side and the valve of the discharge-port side of the
pump.
2) Connect a hose on the suction-side intake and the discharge-port side to the respective vessels.
CAUTION
- Use a flexible hose to absorb pump vibration, and ground the hose.
- Make sure that there will be no external force on any connection part of the pump. Be
especially careful not to have the pump support part of the weight of the hose and the
piping.
- Use a sturdy hose that will not collapse under the strong suction of the pump. Also, make
sure the hose is of more than sufficient pressure rating.
- Use a hose of a diameter the same as or larger than the pump's ports. If you use a hose of
smaller diameter, the pump's performance will be adversely affected, and it may even
malfunction.
- Verify that the particle size doesn’t exceed the particle size limitation (see [9.1 Main
specifications]).
If it exceeds the limitation, attach a strainer to the pump to prevent larger particle from
entering the pump. Failure to do so may cause damage to the pump.
- When testing the piping, either install a valve between the pump's suction inlet and the
discharge outlet and piping, or disconnect the pump from the piping and install plugs so
that there will be no pressure from outside.
- We have done the operation verification of the pump by air. To prevent dust into the
material to be pumped, run the pump dry to clean the inside before finishing installation
work.
Fig3.1

12
3.2 Connecting air piping
WARNING
- Before starting work, make sure that the air compressor is shut off.
1) Connect an air valve, air filter, regulator and if necessary lubricator (hereinafter called the
"peripheral equipment") to hose which connected to compressor. Refer <NOTE>for detail
information.
2) Install these peripheral items supported by brackets, etc., near the pump.
3) Connect the hose from the peripheral equipment to the air valve of the pump's supply port.
CAUTION
- Use a flexible hose to absorb pump vibration, and ground the hose.
- Make sure that there will be no external force on any connection part of the pump. Be
especially careful not to have the pump support part of the weight of the hose and the
piping.
- The piping and the peripheral equipment may become clogged with sludge. Clean the inside
of the piping for 10 to 20 seconds before connecting it to the pump.
- Be sure to sufficiently ground the piping and peripheral equipment.
- For air purging, use clean air such as N2because the purge air will come in contact with the
powder material being pumped.
＜NOTE＞
- Air piping size should be equal to the inlet port of the pump to supply enough air to run the pump.
The air compressor should be able to provide adequate air flow to the pump. Attach the compressor
as close as possible to the pump, considering operability and stability of air pressure.
- If you use a solenoid valve as the air valve, be sure it is a three-way valve. When the valve is closed,
the internal compressed air of the pump will be released, and this will switch the spool to its normal
position.
- Use of a coupler for the connection part of each hose will make operation and maintenance easier.
- If you use the pump intermittently the pump will not require lubrication. However lubrication is
recommended if running the pump continuously for long periods or using very dry air or at high
temperatures. This will guarantee the life of the pumps seals.
*Continuous operation: When the pump operates continuously for longer than 1 hour and is stopped
for less than 15 minutes.
*Lubrication: Use only turbine oil Class 1 grade oil (equivalent to ISO VG 32), under the following
conditions; Oil concentration at 50mg/m³, Absolute pressure at 0.1MPa. Maximum temperature of
20°C and Humidity at 65%.
Fig3.2

13
4. Operation
4.1 Method of operation
CAUTION
- Before starting the pump, make sure that all piping is properly connected.
- Also, before starting the pump, make sure that all the bolts are securely tightened.
- Make sure that the air valve, regulator and the drain valve on the discharge side are closed.
Also, make sure that the valve on the suction side is opened.
1) Start the air compressor. Use dry compressed air.
2) Open the air valve in front of each piece of peripheral equipment, and adjust the supply air
pressure with a regulator to within the permissible range (0.4-0.7MPa).
3) Turn the closed needle valves (5 pcs) to the right about 30 degrees. Adjust the valves if the air
volume is not enough at this time.
4) Press the RESET button, and then slowly open the air valve of the pump.
5) First, verify that material is flowing inside the piping and is being pumped to the discharge side,
and then fully open the air valve.
4.2 Shutdown
- Close the air valve of the pump and shut off the supply air.
CAUTION
- After the pump shuts down, powder material will precipitate and get stuck in the out
chambers. Restarting the pump in such condition may result in damage to the diaphragms
or overload of the center disks, causing the center rod to bend.
Be sure to run the pump dry to remove the residual material from the inlet/outlet hoses, out
chambers, and piping at the end of work.

14
5. Method of cleaning
WARNING
- Before starting operation, make sure that compressed air is not supplied to the pump.
- Before starting operation, make sure that the pump is not pressurized.
1) Remove the hose from the suction side of the pump.
2) Close the flow valve on the discharge side, open the drain valve, and then operate a pump by
starting air pressure for a while to discharge any material remaining inside the pump as much as
possible.
3) Remove the hose from the discharge side, and attach different hoses to the suction side and the
discharge side for cleaning.
4) Remove the hose from the suction side of the pump, run the pump for a while and purge the pump
of remaining material as much as possible.
CAUTION
- Be careful when removing piping. Material will gush out.
- After cleaning by running the pump dry, hang the pump upside down to remove the residual
material.
- Using water or any other liquid to clean the pump may cause powder to absorb water and
stick to the inside of the pump, resulting in operation failure.

15
6. Daily check
- Before starting pump operation, be sure to conduct the following check every day. If any irregularity
is found, do NOT start running the pump until the cause of the irregularity has been found and
corrective measures have been taken.
a) Verify the drain flow through the air filter.
b) Make sure that there are no cracks in the pump casing or piping.
c) Check the tightness of every bolt of the pump.
d) Make sure that the connection parts of the piping and peripheral equipment are not loose.
e) Make sure that the time has not elapsed for replacing any parts of the pump that are to be
replaced at regular intervals.
7. Troubleshooting
7.1 Pump does not run
Cause
A
ction to be taken
The exhaust port (silencer) of pump is clogged
with sludge.
Check and clean the exhaust port and silencer.
Air is not supplied. Start the compressor, and open the air valve and air
regulator.
The supply air pressure is low. Check the compressor and the configuration of air
piping.
Air leaks from connection parts. Check the connection parts and tightness of bolts.
A
ir piping or peripheral equipment is clogged with
sludge.
Check and clean the air piping.
The flow valve on the discharge side is not open. Open the flow valve on the discharge side.
The spool stopped in neutral position. Press the RESET button.
The material piping is clogged with sludge. Check and clean the material piping.
The pump is clogged with sludge. Disassemble the casing, check and clean.
7.2 Pump runs, but fluid does not come out
Cause
A
ction to be taken
The suction lift or discharge head is long. Confirm the piping configuration and shorten the
length.
The discharge-side material piping (including the
strainer) is clogged with sludge.
Check and clean the material piping.
The valve on the suction side is not open. Open the valve on the suction side.
The pump is clogged with sludge. Disassemble the casing, check and clean.
The ball and valve seat are worn out or damaged. Disassemble the manifold, check and replace parts.
7.3 Flow (discharge volume) decreased
Cause
A
ction to be taken
The supply air pressure is low. Check the compressor and configuration of air
piping.
Air piping or peripheral equipment is clogged with
sludge.
Check and clean the air piping.
The discharge-side flow valve opens differently. Adjust the discharge-side flow valve.
Air is taken in together with material. Replenish material and check the configuration of
the suction-side piping.
Chattering occurs. Adjust the supply air pressure and discharge
pressure. Reduce inlet flow valve to adjusting
material pressure and volume.
Icing on air-switching portion. Eliminate ice from air-switching valve and check
and clean the air filter. Use external exhaust hose
to control exhaust air speed. (Refer Fig.2.2)
The material piping (including the strainer) is
clogged with sludge.
Check and clean the material piping and strainer.
The exhaust port (silencer) of the pump is clogged
with sludge.
Check and clean the exhaust port and silencer.
The pump is clogged with sludge. Disassemble the casing, check and clean.

16
7.4 Material leakage from exhaust port (silencer)
Cause
A
ction to be taken
The diaphragm is damaged. Disassemble and check the pump and replace the
diaphragm.
The fastening nuts for the center disk are loose. Disassemble and check the pump, and tighten the
nuts.
7.5 High air consumption during operation
Cause
A
ction to be taken
The seal ring and sleeve are worn out. Disassemble the air-switch portion, check and clean.
Replace parts as necessary.
7.6 Irregular noise
Cause
A
ction to be taken
The supply air pressure too high. Adjust the supply air pressure.
The spool oscillates, and occur ball chattering. Adjust the supply air pressure and discharge
pressure. Reduce inlet flow valve to adjusting
material pressure and volume.
The pump is clogged with sludge with particles of
larger than the permissible diameter.
Disassemble the casing, check and clean.
7.7 Irregular vibration
Cause
A
ction to be taken
The supply air pressure is too high. Adjust the supply air pressure.
The spool oscillates, and occur ball chattering. Adjust the supply air pressure and exhaust
pressure.
Connection parts and pump mounting are loose. Check each connection part and tighten the bolts.
- If any of the above mentioned causes does not apply to your problem, contact your dealer or our
regional office.
8. Returning the product for servicing
8.1 How to use the FAX Sheet
- Copy the FAX Sheet on [10. Trouble-Reporting FAX Sheet], fill out the necessary details regarding
your problem and conditions of operation, and fax it to your dealer or our regional office.
8.2 Before returning the product
1) Purge the pump of material and clean (see [5. Method of cleaning]).
2) Return the product in the same package as when it was first shipped from the factory.
WARNING
- It will be the end-user responsibility to thoroughly wash a clean the pumps to prevent
accidents caused by material leaks.
CAUTION
- Be sure to prevent material leak from pump for safe transport.

17
9. Main body specification
9.1 Main specifications
Type NDP-25 NDP-40 NDP-50 NDP-80
BA□BS□BA□BS□BA□BS□BA□BS□
Nominal Diameter 1″
(25m)
1･1/2″
(40 mm)
2″
(50 mm)
3″
(80mm)
Material
Connection
Suction Port Rc 1 Equivalent to JIS
flange 10K40A
Equivalent to JIS
flange 10K50A
Equivalent to JIS
flange 10K80A
Discharge port
Air
Connection
Supply Port Rc 3/8 Rc 1/2 Rc 3/4
Exhaust Port Rc 3/4 Rc 3/4 Rc 1
Operating Air Pressure 0.2～0.7 MPa
Maximum Discharge
Volume approx. 200 kg/h approx. 500 kg/h approx. 1000 kg/h approx. 1500 kg/h
Maximum Air
Consumption 1600 L/min(ANR) 4000 L/min(ANR) 6000 L/min(ANR) 6000 L/min(ANR)
Operating Ambient
Temperature Range 0～70
°C
Operating Noise 97 dB 95 dB 94 dB 92 dB
Weight 13 kg 20 kg 29 kg 40 kg 37 kg 60 kg 65 kg 102 kg
9.2 Appearance and dimensions
9.2.1 NDP-25 series

18
9.2.2 NDP-40 series
9.2.3 NDP-50 series

19
9.2.4 NDP-80 series
CAUTION
- Concerning section size and the like, it differs depending upon pump body specification.
Please contact your distributor our regional office for detailed information.
＜NOTE＞Method of measurement of operating noise
- With a specified noise meter, the operating noise is measured at measurement points A, B and C, and
the maximum value is to be used.
- The display noise level is the maximum value at flow rate measurement condition.
- The noise level depends on the condition.