Instruction Manual 

For 

Vacuum Drying Oven 

Model 

ADP21 

ADP31

Ver.3 

Yamato Scientific America, Inc. 

Santa Clara, CA 

(800)292-6286 
Contents

 Cautions in Using with Safety................................................................1

• Explanation.................................................................................................................... 1

 Cautions in Using with Safety................................................................2

• Table of Illustrated Symbols .......................................................................................... 2

 Cautions in Using with Safety................................................................3

• Fundamental Matters of “WARNING!” and “CAUTION!” ............................................... 3

 Before Using this unit.............................................................................4

• Requirements for Installation......................................................................................... 4

 Before Using this unit.............................................................................5

• Requirements for Installation......................................................................................... 5

 Before Using this unit.............................................................................6

• Requirements for Installation......................................................................................... 6

 Description and Function of Each Part.................................................7

• Main Unit ....................................................................................................................... 7

 Description and Function of Each Part.................................................8

• Control Panel................................................................................................................. 8

 Description and Function of Each Part.................................................9

• Characters of Thermo Controller................................................................................... 9

 Operation Method .................................................................................10

• Preparation for Operation............................................................................................ 10

 Operation Method ................................................................................. 11

• Operation Mode and Function List .............................................................................. 11

 Operation Method ................................................................................. 11

 Operation Method .................................................................................13

• Operation Mode, Function Setting Key, and Characters ............................................. 13

 Operation Method .................................................................................14

• Setting of Overheating Prevention Device .................................................................. 14

 Operation Method .................................................................................15

• Fixed Temperature Operation...................................................................................... 15

 Operation Method .................................................................................16

• Quick Auto Stop Operation.......................................................................................... 16

 Operation Method .................................................................................17

• Auto Stop Operation.................................................................................................... 17

 Operation Method .................................................................................18

• Auto Stop Operation.................................................................................................... 18

 Operation Method .................................................................................19

• Auto Start Operation.................................................................................................... 19
 Operation Method .................................................................................20

• Auto Start Operation.................................................................................................... 20

 Operation Method .................................................................................21

• Other Functions........................................................................................................... 21

 Handling Precautions ...........................................................................22

 Maintenance Method.............................................................................23

• Daily Inspection and Maintenance .............................................................................. 23

 Long storage and disposal...................................................................24

• When not using this unit for long term / When disposing ............................................ 24

 In the Event of Failure... .......................................................................25

• Safety Device and Error Code..................................................................................... 25

 In the Event of Failure... .......................................................................26

 In the Event of Failure... .......................................................................26

• Trouble Shooting ......................................................................................................... 26

 After Service and Warranty ..................................................................27

 Specification..........................................................................................28

 Wiring Diagram......................................................................................29

 Replacement Parts Table......................................................................30

 Reference...............................................................................................31

• List of Dangerous Substances .................................................................................... 31
Cautions in Using with Safety 

Explanation 

MEANING OF ILLUSTRATED SYMBOLS

Various symbols are used in this safety manual in order to use the unit without

danger of injury and damage of the unit. A list of problems caused by ignoring

the warnings and improper handling is divided as shown below.Be sure that you

understand the warnings and cautions in this manual before operating the unit.

WARNING! If the warning is ignored, there is the danger of a problem that

may cause a serious accident or even fatality.

CAUTION! If the caution is ignored, there is the danger of a problem that may

cause injury/damage to property or the unit itself.

Meaning of Symbols

This symbol indicates items that urge the warning (including the caution).

A detailed warning message is shown adjacent to the symbol.

This symbol indicates items that are strictly prohibited.

perform.

This symbol indicates items that should be always performed.

A detailed message with instructions is shown adjacent to the symbol.

Illustrated Symbols

1 
Cautions in Using with Safety 

Table of Illustrated Symbols 

Warning

Warning, 

generally 

Warning, 

high voltage

Warning, 

high temperature 

Warning, 

drive train 

Warning, 

explosive 

Caution 

Caution, 

generally 

Caution, 

electrical shock 

Caution, 

scald 

Caution, 

no road heating 

Caution, 

not to drench 

Caution, 

water only 

Caution, 

deadly poison 

Prohibit 

Prohibit, 

generally 

Prohibit, 

inflammable 

Prohibit, 

to disassemble 

Prohibit, 

to touch 

Compulsion 

Compulsion, 

generally 

Compulsion, 

connect to the 

grounding 

terminal 

Compulsion, 

install on a flat 

surface 

Compulsion, 

disconnect the

power plug 

Compulsion, 

periodical 

inspection 

2 
Cautions in Using with Safety 

Fundamental Matters of “WARNING!” and “CAUTION!” 

WARNING!

Do not use this unit in an area where there is flammable or explosive gas 

Never use this unit in an area where there is flammable or explosive gas. 

This unit is not explosion-proof. An arc may be generated when the power switch is turned on or off, 

and fire/explosion may result. (Refer to page31 “List of Dangerous Substances”.) 

Always ground this unit

Always ground this unit on the power equipment side in order to avoid electrical shock due to a power

surge. 

If a problem occurs

If smoke or strange odor should come out of this unit for some reason, turn off the power key right 

away, and then turn off the circuit breaker and the main power. Immediately contact a service

technician for inspection. If this procedure is not followed, fire or electrical shock may result. Never

perform repair work yourself, since it is dangerous and not recommended. 

Do not use the power cord if it is bundled or tangled

Do not use the power cord if it is bundled or tangled. If it is used in this manner, it can overheat and

fire may be caused. 

Do not process, bend, wring, or stretch the power cord forcibly

Do not process, bend, wring, or stretch the power cord forcibly. Fire or electrical shock may result. 

Substances that can not be used

Never use explosive substances, flammable substances and substances that include explosive or 

flammable ingredients in this unit. Explosion or fire may occur.

Do not disassemble or modify this unit

Do not disassemble or modify this unit. Fire or electrical shock or failure may be caused. 

Do not touch high-temperature parts 

The inside of the body or the door may become hot during and just after operation. It may cause burns. 

CAUTION!

During a thunder storm

During a thunderstorm, turn off the power key immediately, then turn off the circuit breaker and the main

power. If this procedure is not followed, fire or electrical shock may be caused. 

3 
Before Using this unit 

Requirements for Installation 

WARNING!

1. Always ground this unit

• 

• 

• 

Connect the power plug to a receptacle with grounding connectors. 

Do not forget to ground this unit, to protect you and the unit from electrical shock in case of 

power surge. Choose a receptacle with grounding connectors as often as possible. 

Do not connect the grounding wire to a gas pipe, or by means of a lightning rod or telephone 

line. A fire or electrical shock will occur. 

2. Choose a proper place for installation

• 

♦ 

♦ 

♦ 

♦ 

♦ 

♦ 

♦ 

Do not install this unit in a place where:

Rough or dirty surface. 

Flammable gas or corrosive gas is generated. 

Ambient temperature exceeds 35°C. 

Ambient temperature fluctuates violently. 

There is direct sunlight. 

There is excessive humidity and dust. 

There is a constant vibration. 

• Install this unit on a stable place with the space as shown below.

More than 

20cm

More than 

20cm

More than 15cm

Front side

Main Unit

More than 50cm

3. Do not use this unit in an area where there is flammable or explosive gas

• Never use this unit in an area where 

there is flammable or explosive gas. 

This unit is not explosion-proof. An 

arc may be generated when the 

power switch is turned ON or OFF, 

and fire/explosion may result. 

ADP31

4 
Before Using this unit 

Requirements for Installation 

4. Do not modify

• Modification of this unit is strictly prohibited. This could cause a failure. 

5. Installation on horizontal surface 

• Set this unit to the flattest place. Setting this unit on rough or slope place could cause the 

vibration or noise, or cause the unexpectible trouble or malfunction. 

5 
Before Using this unit 

Requirements for Installation 

CAUTION!

6. Choose a correct power distribution board or receptacle

• Choose a correct power distribution board or receptacle that meets the unit’s rated electric 

capacity. 

Electric capacity: ADP21: 115V AC, 6A 

ADP31: 115V AC, 10A 

NOTE) 

There could be the case that the unit does not run even after turning ON the power. Inspect 

whether the voltage of the main power is lowered than the specified value, or whether other 

device(s) uses the same power line of this unit. If the phenomena might be found, change the

power line of this unit to the other power line. 

7. Handling of power code

• 

• 

• 

• 

Do not entangle the power cord. This will cause overheating and possibly a fire. 

Do not bend or twist the power cord, or apply excessive tension to it. This may cause a fire

and electrical shock. 

Do not lay the power cord under a desk or chair, and do not allow it to be pinched in order to 

prevent it from being damaged and to avoid a fire or electrical shock. 

Keep the power cord away from any heating equipment such as a room heater. The cord's 

insulation may melt and cause a fire or electrical shock. 

• 

• 

If the power cord becomes damaged (wiring exposed, breakage, etc.), immediately turn off the 

power at the rear of this unit and shut off the main supply power. Then contact your nearest 

dealer for replacement of the power cord. Leaving it may cause a fire or electrical shock. 

Connect the power plug to the receptacle which is supplied appropriate power and voltage. 

8. Before/after installing 

• 

• 

It may cause injure to a person if this unit falls down or moves by the earthquake and the 

impact. etc..To prevent, take measures that the unit cannot fall down, and not install to busy 

place. 

Touching the unit may cause a burn during and just after the operation. To prevent, take 

measures that putting up a notice of operating etc.. 

6 
Description and Function of Each Part 

Main Unit 

Purge valve 

Front view

Vacuum valve 

Door

Inspection

window

Vacuum meter

Control panel

Power switch

Rear view

Power cord

7 
Description and Function of Each Part 

Control Panel 

 

POWER

1 START/STOP Key: Starts/stops the operation. 

2 ▲▼ Key: Uses for rising UP/lowering DOWN the setting value. 

3 ENTER Key: Settles the inputted value.

4 FIXED TEMP Key: Chooses the fixed temperature operation. 

5 TIMER Key: Chooses the timer operation (Quick Auto Stop/Auto Stop/Auto Start). 

6 SUBMENU Key: Uses for setting the overheating prevention temperature, calibration

offset temperature, and key lock function. 

7 HEATER Lamp: Lights while the heater works. 

8 ALARM Lamp: Lights up when an error occurs. (Buzzer sounds simultaneously.) 

9 AUTO STOP Lamp: Blinks while setting quick auto stop timer or auto stop timer.

Lights while quick auto stop timer or auto stop timer is running. 

10 AUTO START Lamp: Blinks while setting auto start timer.

Lights while auto start timer is running. 

11 FIXED TEMP Lamp: Blinks while setting fixed temperature operation. 

Lights while fixed temperature operation is running. 

12 Measurement Temperature 

 Display:

Displays the measured temperature, setting character, alarm

information. 

13 Setting Temperature 

 Display:

Displays the setting temperature, setting value for timer mode,

remaining time. 

14 Overheating Prevention 

Temperature Display:

Displays the setting temperature for overheating prevention device. 

15 Power Switch: Turns ON/OFF the main power. 

15

12

13

14

1

4 6

5

2

3

11

10

9

8

7

8 
Description and Function of Each Part 

Characters of Thermo Controller 

The characters VS3 controller shows are as follows: 

Character Identifier Name Purpose

FiX Fixed Temperature 

Setting Mode 

Used for starting the fixed temperature

operation. 

Sv Temperature Setting Used for setting the temperature. 

AStP Timer Setting Mode 

Display 

Represents the setting of quick auto stop or 

auto stop operation. 

AStr Timer Setting Mode 

Display Represents the setting of auto start operation. 

tim Time Setting Used for setting the time. 

End Time Up Displays when the timer operation is 

completed. 

cAL Calibration Offset 

Setting 

Used for inputting the calibration offset 

temperature. (Refer to Page 21 "Use 

calibration offset function".) 

oH Overheating Prevention 

Setting 

Used for setting temperature for overheating 

prevention device. (Refer to Page 14 "Setting 

of Overheating Prevention Device ".) 

LocK Key Lock 

Locks the keys on control panel to protect from 

unnecessary operation. (Refer to Page 21 

"Use lock function".) 

* Also refer to Page 14 "Setting of Overheating Prevention Device". 

9 
Operation Method 

Preparation for Operation 

Set the shelf: Use the shelf of attached accessory. Permissible load of the shelf is 

approximately 15kg. Do not put too much sample. 

Set sample: Set samples with space between each of them. Make room more than

30% of the shelf in order to keep accuracy of temperature. 

Connect the power code: Connect the power code to a proper receptacle securely. 

Read the following without fail before using the vacuum pump 

Use a vacuum pump with air volume displacement of approximately 50 liters/min. 

The vacuum pump shall be connected to the main unit before starting operation. 

Check no vacuum air leakage exists before turning on the power of this unit.

Make bath to vacuum state: Close the purging valve to vacuum the bath. Turn on the power switch

of vacuum pump after opening the vacuum valve.

After the power switch of vacuum pump is turned on, the scale at the

front of the unit gradually slants to the left until it reaches to 

approximately 100 Pa. 

Vacuuming time is around seven minutes for ADP21 and around ten

minutes for ADP31under an ambient temperature. 

Return bath to 

atmospheric pressure: Close the vacuum valve and open the purge valve.

Turn off the power switch of the vacuum pump after returning the inlet side of pump to

atmospheric pressure. If not, oil inside the pump may flow back to the bath.

When using powder-type sample, open the purging valve gradually to avoid powder flying.

10 
Operation Method 

Operation Mode and Function List 

All the operation mode of this unit is as follows; 

No. Name Description Page

1. Fixed Temperature 

 Operation 

Pressing the FIXED TEMP key enters into the fixed

temperature operation setting mode. 

Pressing it again enters into the temperature setting mode.

The "▲▼" are used to set temperature. 

Pressing the START/STOP key starts or stops operation. 

15 

2. Quick Auto Stop 

 Operation 

This operation is used to specify the period up to automatic

stop during operation. 

The period up to operation stop can be set by pressing the 

TIMER key during fixed temperature operation. 

The "▲▼" are used to set the time. 

Pressing the START key starts the quick auto stop operation, 

activates the timer function and stops the operation

automatically after specified period. 

16 

3. Auto Stop Operation 

This operation is used to specify the automatic stop time in the 

fixed temperature operation. 

Pressing the TIMER key displays "AStp". 

The setting temperature "SV" can be set by pressing the

ENTER key.

The operation time "tim" can be set by pressing it again. 

Pressing the START/STOP key starts the auto stop operation. 

17 

4. Auto Start Operation 

This operation is used to specify the period up to automatic

start after power on. 

Pressing the TIMER key displays "AStr". 

The setting temperature "SV" can be set by pressing the

ENTER key.

The operation time "tim" can be set by pressing it again. 

Pressing the START/STOP key starts the auto start operation. 

19 

NOTE) This unit is impossible to be changed the mode during the operation. If the mode requires to be

changed, stop the operation. 

Operation Method 

11 
The operation function of this unit is as follows; 

No. Name Description Page

Auto overheating 

 prevention function 

This function is set to be automatically activated 

(auto reset) when the temperature exceeds the 

setting temperature by 12°C. 

1. 

Overheating

 prevention

 function Overheating

 prevention device 

Though the device shares power source, display,

and key input with the controller, it has independent

temperature measurement circuit, CPU, sensor and 

output circuit. Overheating prevention temperature 

can be set using the operation panel.

The unit stops operation when the device is 

activated. The unit starts operation again when the 

POWER switch is pressed again (manual reset). 

14 

2. Calibration offset function 

This calibration offset function is for calibrating the 

difference occurred between the required in- furnace 

temperature and control temperature (sensor 

temperature) of the controller. This unit can be 

calibrated toward either plus side or minus side of 

the whole temperature range. 

21 

3. 

Overheating prevention 

 temperature calibration 

 function 

The temperature of overheating prevention device is 

automatically corrected when the temperature of 

controller is collected. 

-

4. Recovery at power failure

The unit starts operation with the same condition as 

just before power failure if it occurs during operation. 

Press the START/STOP key to start the unit again. 

-

5. Setting value locking This function locks the established operation status. 

It can be set and cancelled with the SUBMENU key. 21 

12 
Operation Method 

Operation Mode, Function Setting Key, and Characters 

The operation mode setting and function setting use the key operation and characters show in the

following figure. 

13 
Operation Method 

Setting of Overheating Prevention Device 

The unit has the overheating prevention device (manual reset) that consists of independent temperature

measurement circuit, CPU, sensor and output circuit (it shares power source, display, and key input with 

the controller) in addition to the automatic overheating prevention function (auto reset) in the controller.

Setting range/function 

The unit has failsafe functions against overheating. One of them is built in the controller and previously

set at factory shipment so to be automatically activated when the temperature exceeds the setting 

temperature of temperature controller by 12°C, where the heater repeats on and off. 

The other is united with the controller, which can be set by operating the keys on the controller.

The setting range of latter is from 0°C to 1300°C. 

In case the temperature in furnace exceeds the setting temperature of controller to reach to that of 

overheating prevention device, the circuit is shut off and "Er19" is displayed with blinking on the screen of

controller with buzzer sound. 

If the device is once activated,"Er19"continues to be displayed until the power is newly turned on. 

Temperature setting procedure 1. Turn on the power (turn on the breaker in front) 

• The default value is displayed for about four seconds after 

turning on the power. The screen then displays the initial 

setting. The current temperature in furnace, operation

mode character and setting temperature of overheating

prevention device are displayed on respective screens. 

2. Set the temperature for overheating prevention 

1 Press the SUBMENU key.

2 Press the " ▼ ▲ " several times to select the setting

character of overheating prevention temperature "OH". 

3 Press the ENTER key. The current setting temperature is

displayed with blinking on the setting temperature screen. 

Note: To prevent improper operation, set the value 12°C or more

over the setting temperature of controller.

4 Select the value using the "▼▲"and then press the

ENTER key. This completes the setting. 

Notes: 

• 

• 

• 

• 

• 

The standard setting temperature of device is "the maximum setting temperature of unit plus 

12°C" or "setting temperature plus 12°C". 

The setting range of overheating prevention device is from 0°C to 1300°C. Improper setting 

of temperature may cause inoperative of unit, malfunction of device, e.g. it is activated during 

increasing in temperature in furnace, or unexpected accidents such as fire disaster. 

To prevent such matters, set a proper value. 

The temperature is set at 252°C for the ADP21 and ADP31 at factory shipment。

In some case, the overheating prevention device is possible to be activated by mistake when 

its yield temperature is set to around room temperature. 

The purpose of overheating prevention device is to protect the unit from overheating. It does 

not intend to protect the samples, or to protect them from the accident caused by the use of 

explosive or inflammability. 

14 
Operation Method 

Fixed Temperature Operation 

Fixed temperature 

operation procedure 

1. Turn on the power (turn on the breaker in front) 

 The default value is displayed for about four seconds after turning 

on the power. The screen then displays the initial setting. The 

current temperature in furnace, operation mode character and 

setting temperature of overheating prevention device are displayed

on respective screens.

2. Select the operation mode 

• Press the FIXED TEMP key to display "FIX", which indicates the 

fixed temperature operation, on the center display screen. 

3. Set the temperature 

• Press the FIXED TEMP key again. 

• The setting temperature screen displays the character "SV" 

which indicates the temperature setting. Also it displays the

current setting temperature with blinking. The FIXED TEMP 

lamp blinks, too. 

• Set the temperature by pressing the "▼▲". 

4. Start operation 

• Press the orange START/STOP key for about one second. 

The unit starts operation and the blinking FIXED TEMP lamp 

lights on. 

5. Stop operation 

• Press the orange START/STOP key for about one second. 

The unit stops operation and the FIXED TEMP lamp lights off. 

The screen returns to the initial setting screen. 

To correct or check setting... 

Press the FIXED TEMP key again to correct or check the setting. 

Changing the setting temperature during operation is also possible by pressing the FIXED TEMP key.

Measurement temperature screen: 

Displays the current temperature in furnace. 

Setting temperature screen: 

Displays the operation mode character. (Refer to Page 9) 

Overheating prevention screen: 

 Displays the setting temperature of overheating prevention device 

15 
Operation Method 

Quick Auto Stop Operation 

Quick auto stop 

 operation procedure 

This operation is used to specify the period up to automatic stop, i.e., 

sets the auto stop timer during operation. 

1. Set the time up to stop during fixed temperature operation 

• 

• 

• 

• 

Check that the FIXED TEMP lamp lights on and that the unit is 

under operation. 

Press the TIMER key.

The measurement temperature display screen displays the 

character "tim", which indicates the timer setting. The setting 

temperature display screen displays the current setting time with 

blinking. 

Select the time by pressing the "▼▲". 

Timer function: • The maximum setting time is "999 hours and 50 minutes". 

• The time can be set in increments of a minute under 99 hours 

and 59 minutes. 

• It can be set in increment of ten minutes over 100 hours. 

• The "▼▲"can change the setting time quickly when it is pressed

continuously. Press them discontinuously when fine adjustment

is needed. 

2. Start timer operation 

• Press the START/STOP key for one second after deciding the 

time. 

• Timer operation starts with the FIXED TEMP and AUTO STOP 

lamps lighting on. 

• The timer is activated at the point when the START/STOP key is

pressed. 

3. Stop/terminate timer operation 

• The operation stops automatically at setting time. 

• Buzzer continues to sound for about five seconds at operation

stop. 

• The setting temperature screen displays the character "End",

which indicates termination of operation, with the FIXED TEMP 

and AUTO STOP lamps lighting on. Press the START/STOP

key to terminate the timer operation mode. The screen returns

to the initial setting screen. 

To correct or check setting... 

Changing the setting temperature during operation is possible by pressing the FIXED TEMP key. Press 

the ENTER key after changing the setting. 

Changing the setting temperature during operation is available by pressing the FIXED TEMP key. Press

the ENTER key after changing the setting. 

Press the ▼ key to display the setting temperature, operation mode and residual time on the setting

temperature screen. 

16 
Operation Method 

Auto Stop Operation 

Auto stop operation 

 procedure 

This operation is used to specify the automatic stop time in the fixed

temperature operation. 

1. Set stop time 

1 Press the TIMER key on the initial screen. 

Press the TIMER key again. The setting temperature display 

screen displays the character "AstP", which indicates the auto

stop operation, with blinking. 

2 Press the ENTER key.

The measurement temperature screen displays the character 

"SV", which indicates the temperature setting. The setting

temperature screen displays the current setting temperature with

blinking. The AUTO STOP lamp blinks, too. 

3 Set the temperature using the "▼▲". 

4 Press the ENTER key again. 

The measurement temperature display screen displays the 

character "tim", which indicates the timer setting. The setting 

temperature display screen displays the current setting time with 

blinking. 

5 Set the time using the "▼▲". 

Timer function: • The maximum setting time is "999 hours and 50 minutes". 

• The time can be set in increments of a minute under 99 hours 

and 59 minutes. 

• It can be set in increment of ten minutes over 100 hours. 

• The "▼▲"can change the setting time quickly when it is pressed

continuously. Press them discontinuously when fine adjustment

is needed. 

2. Start timer operation 

• Press the START/STOP key for one second after deciding the 

time. 

• Timer operation starts with the AUTO STOP lamp lighting on. 

• The timer is activated at the point when the temperature in

furnace (measurement temperature) reaches to the setting

temperature.

17 
Operation Method 

Auto Stop Operation 

3. Stop/terminate timer operation 

• The operation stops automatically at setting time. 

• Buzzer continues to sound for about five seconds at operation

stop. 

• The setting temperature screen displays the character "End",

which indicates termination of operation, with the FIXED TEMP 

and AUTO STOP lamps lighting on. Press the START/STOP

key to terminate the timer operation mode. The screen returns

to the initial setting screen. 

To correct or check setting... 

Changing the setting temperature or time during operation is possible by pressing the TIMER key. Use

the "▼▲" to change the setting value. Press the ENTER key respectively after changing the setting. 

Press the "▼" to display the setting temperature, operation mode and residual time on the setting

temperature screen. 

18 
Operation Method 

Auto Start Operation 

Auto start operation 

 procedure 

This operation is used to specify the period up to automatic start after 

power on. 

1. Set start time 

1 Press the TIMER key on the initial screen. 

Press the TIMER key again. The setting temperature display 

screen displays the character "Astr", which indicates the auto start

operation, with blinking. 

2 Press the ENTER key.

The measurement temperature screen displays the character 

"SV", which indicates the temperature setting. The setting

temperature screen displays the current setting temperature with

blinking. The AUTO START lamp blinks, too. 

3 Set the temperature using the "▼▲". 

4 Press the ENTER key again. 

The measurement temperature display screen displays the 

character "tim", which indicates the timer setting. The setting 

temperature display screen displays the current setting time with 

blinking. 

5 Set the time using the "▼▲". 

Timer function: • The maximum setting time is "999 hours and 50 minutes". 

• The time can be set in increments of a minute under 99 hours 

and 59 minutes. 

• It can be set in increment of ten minutes over 100 hours. 

• The "▼▲"can change the setting time quickly when it is pressed

continuously. Press them discontinuously when fine adjustment

is needed. 

2. Start timer operation 

• Press the START/STOP key for one second after deciding the 

time. 

• Timer operation starts with the AUTO START lamp lighting on. 

19 
Operation Method 

Auto Start Operation 

3. Stop/terminate timer operation 

• The operation starts automatically at setting time. 

• Press the START/STOP key for one second to stop or terminate

operation. The screen returns to the initial setting screen. 

To correct or check setting... 

Changing the setting temperature or time during operation is possible by pressing the TIMER key. Use

the "▼▲" to change the setting value. Press the ENTER key respectively after changing the setting. 

They are not changeable after the unit starts operation. In this case, stop the operation by pressing the 

START/STOP key, then set the value again. 

Press the "▼" to display the setting temperature, operation mode and residual time on the setting

temperature screen. 

20 
Operation Method 

Other Functions 

Use calibration offset function 

Calibration offset is a function which corrects the difference between the temperature in furnace and

that of controller (sensor temperature) if arises. The function parallel corrects the difference either to

the plus or minus side within the whole temperature range of unit. The function can be set or

cancelled by the SUBMENU key.

1 Start operation with the target setting temperature. Check the

temperature in furnace (temperature of sample) with a thermograph after 

it is stabilized. 

2 Check the difference between the setting temperature and that in furnace 

(temperature of sample). 

3 Press the SUBMENU key. Select the character "cAL", which indicates 

the calibration offset, using the "▲▼", and then press the ENTER key.

4 Input the difference using the "▲▼" and then press the ENTER key.

This completes the setting. 

 The setting range of offset correction temperature is +99°C to plus side and 

-99°C to minus side respectively. 

When it is set to the minus side, the temperature on the measurement

temperature display screen falls by the setting temperature, while the

temperature on furnace rises. 

When it is set to the minus side, the temperature on the measurement

temperature display screen rises by the setting temperature, while the 

temperature on furnace falls. 

 The unit has two-point correction function, which performs offset between

low-temperature zone and high-temperature zone. Please consult our local

branch office when carrying out validation of temperature controller. 

Current temperature 

Corrected temp. to plus side 

Corrected temp. to minus side 

Use lock function 

This function locks the operation status previously set. The function can be set or cancelled by the 

SUBMENU key.

1 Press the SUBMENU key. Select the character" "Lock", which indicates 

the lock of setting value, using the "▲▼", and then press the ENTER key.

2 The setting temperature screen displays "oFF". The setting value is 

locked when it is turned to "on" using the "▲". 

3 Press the SUBMENU key again to cancel the lock. Select the character"

"Lock", which indicates the lock of setting value, using the "▲▼", and 

then press the ENTER key. Select "oFF" with the "▼" and then press 

the ENTER key to cancel the function. 

 All keys other than the START/STOP and SUBMENU keys are lock when the

lock function is on. 

21 
Handling Precautions 

WARNING!

If a problem occurs 

If smoke or strange odor should come out of this unit for some reason, turn off the power key 

right away, and then turn off the circuit breaker and the main power. Immediately contact a

service technician for inspection. If this procedure is not followed, fire or electrical shock may 

result. Never perform repair work yourself, since it is dangerous and not recommended.

Substances that cannot be used 

Never use explosive substances, flammable substances and substances that include explosive 

or flammable ingredients in this unit. Explosion or fire may occur. (Refer to page31 “List of 

Dangerous Substances”.)

CAUTION!

Do not step on this unit 

Do not step on this unit. It will cause injury if this unit fall down or break.

Do not put anything on this unit 

Do not put anything on this unit. It will cause injury if fall.

During a thunder storm 

During a thunderstorm, turn off the power key immediately, then turn off the circuit breaker and 

the main power. If this procedure is not followed, fire or electrical shock may be caused.

Do not touch high-temperature parts 

Some parts of this unit may become hot during and just after operation. It may cause burns.

Sample loading 

Overload of samples may cause the malfunction of the temperature control. Do not use this unit 

with too much samples. Leave a certain space between samples.

Return after power failure 

When power is supplied after a power failure, the device automatically starts operation again with

the same state as just before the power failure. It is danger that the device starts unattached

operation after a power failure. We recommend for you to turn off the switch of this unit if a

power failure occurs during operation.

22 
Maintenance Method 

Daily Inspection and Maintenance 

For the safety use of this unit, please perform the daily inspection and maintenance without fail. 

Using the city water to this unit might attach dirt. Do inspect and maintain this point while performing

daily inspection and maintenance. 

WARNING!

• Disconnect the power cable from the power source when doing an inspection or maintenance

unless needed. 

• Perform the daily inspection and maintenance after returning the temperature of this unit to the

normal one. 

• Do not disassemble this unit. 

CAUTION!

• Use a well-drained soft cloth to wipe dirt on this

unit. Do not use benzene, thinner or cleanser for

wiping. Do not scrub this unit. Deformation, 

deterioration or color change may result in. 

For any questions, contact Yamato Service Office.

23 
Long storage and disposal 

When not using this unit for long term / When disposing 

CAUTION!

When not using this unit for long term... 

• Turn off the power and disconnect the power cord.

WARNING!

When disposing... 

• Keep out of reach of children. 

• Remove the door and driving parts. 

• Treat as large trash. 

Environmental protection should be considered 

We request you to disassemble this unit as possible and recycle the reusable parts considering to the 

environmental protection. The feature components of this unit and materials used are listed below. 

Component Name Material 

Exterior Parts 

Outer covering Steel plate, Melamine and epoxy composite resin coating 

Chamber Stainless steel SUS304

Inspection window Reinforced glass and polycarbonate resin 

Heat insulation material Composites with glass fiber and others

Piping Copper pipe

Intake/exhaust valve Brass 

Vacuum meter Composites with glass, brass and others 

Electrical Parts 

Switches, Relays Composites with resin, copper and others 

Control panel frame ABS resin 

Board Composites with glass fiber and others

Heater Steel and mica heater 

Power cord Composites with synthetic rubber, copper, nickel and others 

Wiring Material Composites with glass fiber, flame resistance vinyl, copper, nickel 

and others 

Labels Resin material

Leg with rubber Synthetic rubber, Steel 

24 
In the Event of Failure... 

Safety Device and Error Code 

This unit has an automatic diagnosis function built in the controller and safety devices independent of the 

controller. The table below shows the cause and the solution method when the safety device operates. 

Error Code: 

When an abnormal condition occurs, an error code appears and the alarm lamp lights in the controller,

the buzzer sounds simultaneously. Record the error code and turn off the power of device 

immediately.

Safety Device Notify Cause/Solution 

Sensor trouble detection “ALARM” lamp lights on, 

“Er.01” appears 

• Temperature sensor is broken or 

disconnected. 

• Make a call for service. 

SSR short-circuit detection “ALARM” lamp lights on, 

“Er.02” appears 

• Triac is in short-circuit 

• Make a call for service. 

Heater disconnecting detection “ALARM” lamp lights on, 

“Er.03” appears 

• Heater is disconnected. 

• Make a call for service. 

Memory error “ALARM” lamp lights on, 

“Er.15” appears 

• Failure in internal memory. 

• Make a call for service. 

Internal communication error “ALARM” lamp lights on, 

“Er.17” appears 

• Failure in internal communication or

temperature inputting circuit. 

• Make a call for service. 

Overheating “ALARM” lamp lights on, 

“Er.19” appears 

• Overheating prevention device is in 

operation. 

• Reset the power supply, and then

adjust the setting temperature of the 

overheating protection device. 

• If the state does not recover, make a 

call for service. 

Measurement temperature 

error 

“ALARM” lamp lights on, 

“--------” appears 

• Measurement value is out of display 

range. 

• Make a call for service. 

25 
In the Event of Failure... 

In the Event of Failure... 

Trouble Shooting 

Before call us... 

Condition Possible Causes

The device does not start when 

turning on the power switch. 

• Power plug is not connected to the receptacle correctly. 

• Power failure. 

Temperature fluctuates during the 

operation. 

• Too much samples. 

• Wind from air conditioner directly blows. 

• The change of ambient temperature is remarkable. 

• Samples are too moist. 

• The power supply voltage is lower than the proper value. 

In the case if the error other than listed above occurred, turn off the power switch and primary

power source immediately. Contact the shop of your purchase or Yamato Service Office.

26 
After Service and Warranty 

In Case of Request for Repair 

If the failure occurs, stop the operation, turn OFF the power switch, and unplug the power plug.

Please contact the sales agency that this unit was purchased, or Yamato sales office. 

< Check following items before contact > 

◆ Model Name of Product 

◆ Production Number 

◆ Purchase Date 

◆ About Trouble (in detail as possible) 

See the production plate attached to this unit. 

Minimum Retention Period of Performance Parts for Repair 

The minimum retention period of performance parts for repair of this unit is 5years after

discontinuance of this unit. 

The "performance part for repair" is the part that is required to maintain this unit. 

27 
Specification 

Model ADP21 ADP31

Internal dimensions W200×D250×H200 mm W300×D300×H300 mm 

External dimensions W360×D411×H535 mm W420×D463×H639 mm 

Interior Stainless steel SUS304 

Internal capacity 10L 27L 

Permissible load of shelf Approx. 15kg/one shelf 

Shelf material Aluminum 

Number of shelf step 2 3 

Pitch of shelf 63mm 71mm 

Standards 

Intake Outer diameter: 18mm 

Method Decompression, radiation heating

Operating temperature range Room Temperature+5°C to 240°C

Operating vacuum degree range 101 to 0.1KPa 

Temperature adjustment 

 accuracy 

±1.5°C (at 240°C, no load)

Temperature distribution 

 accuracy 

Performanc

Within ±10°C (at 240°C, no load) 

e 

Time required to reach 

 highest temperature Approx. 70min. Approx. 100min. 

Thermo regulator PID control by microcomputer (VS3 controller) 

ON/OFF control by microcomputer (VS3 controller) 

Overheating prevention device Temperature control circuit shares the power source with overheating

prevention circuit. Temperature measurement circuit, CPU,

sensors, and output circuit are independent respectively. 

Sensor for temperature control 

Sensor for 

 overheating prevention 

K-thermocouple 

(Double sensor for temperature control and overheating prevention)

Temperature setting system Digital setting (also for overheating prevention device) 

Temperature display system Digital display 

Mica heater Heater

680W 1.05KW

Heat insulation material Rock wool 100 mm 

Inspection window 

Reinforced glass, 12mm thickness with polycarbonate resin 

protection plate 

Vacuum meter Bourdon tube type, scale range 0 to 0.1 mPa 

Function 

Safety device 

Over current earth leakage breaker, Dual overheating prevention

function 

Key input 

Display:4digits 7segments 10mm LED (green) 

Setting:4digits 7segments 8mm LED (red) 

Setting of overheating prevention:4digits 7segments 8mm LED (red) 

Monitor lamp Heater lamp, Alarm lamp, Timer lamp.Fixed lamp.

 Function key Select from Fixed/ Auto stop/Auto start/Sub menu 

Vacuum control Bourdon tube display, manually control by vacuum valve and purge

valve 

Operation 

Safety function Circuit breaker , Dual overheating prevention function, Error display 

Power supply 115V AC, 50/60Hz, 6A 115V AC, 50/60Hz, 10A 

Weight Approx. 30Kg Approx. 55Kg

Shelf (aluminum punching metal) Accessory 2 pcs. 3pcs. 

28 
Wiring Diagram 

1

2

3

4

ELB

AC115V

5

1

2

3

1

2

3

4

5

6

1

2

1

`

1

`

1

`

1

`

1

2

3

1

2

1

2

3

P

X1

X1

SSR ‚P

‚Q

‚R

‚S

TH

{

|

{

|

CN5

CN4

CN1

CN2

TB1

TB2

CN8

CN9

CN1

CN2

PIO

TIC

CT

G

Symbol Part name Symbol Part name

H Heater X1 Main relay

TIC Control board (planar) SSR Solid state relay 

PIO Display circuit board TH K-thermocouple 

ELB Circuit breaker CT Overcurrent transformer 

29 
Replacement Parts Table 

Part Name Code No. Specification Manufacturer 

ADP21 Upper Heater ADP-21-40100 115V 80W Yamato Scientific

ADP21 Side and Lower Heater ADP-21-40110 115V 200W Yamato Scientific

ADP31 Upper Heater ADP-31-40070 115V 150W Yamato Scientific

ADP31 Side and Lower Heater ADP3140080 115V 300W Yamato Scientific

Control board DX-301-00052 Yamato Scientific

Display circuit board DX-301-00051

VS-3 fixed value type (control

board and display circuit board

are replaced together.) Yamato Scientific

Ribbon cable ADP-21-00008 Length: 300mm Yamato Scientific

Circuit breaker ADP-21-00019 FB323B-15 15A Fuji Electric 

Main relay DX-301-00043 AHE1254 120V Matsushita 

Solid state relay DX-301-00035 TRS5225 Toho Electronics 

Temperature sensor ADP-21-30048 K-thermocouple Yamato Scientific 

Vacuum/Purge valve ADP-21-00009 DC-42B BS Fujikin

Vacuum gauge ADP-21-10004 GK25-A40 Nagano Keiki

Door gasket (ADP21) ADP-21-40080 Silicon rubber Yamato Scientific

Door gasket (ADP31) ADP-31-40060 Silicon rubber Yamato Scientific

Window glass (ADP21 and 31) ADP2140260 Hard glass Yamato Scientific

30 
Reference 

List of Dangerous Substances 

Never use explosive substances, flammable substances and substances that include explosive 

or flammable ingredients in this unit.

EXPLOSIVE 

Ethylene glycol dinitrate (nitro glycol), Glycerin trinitrate (nitroglycerine), Cellulose 

nitrate (nitrocellulose), and other explosive nitrate esters 

Trinitrobenzene, Trinitrotoluene, Trinitrophenol (picric acid), and other explosive

nitro compounds 

EXPLOSIVE: 

Acetyl hidroperoxide (peracetic acid), Methyl ethyl ketone peroxide, Benzyl

peroxide, and other organic peroxides

FLAMMABLE 

IGNITING:

Lithium (metal), Potassium (metal), Sodium (metal), Yellow phosphorus, 

Phosphorus sulfide, Red phosphorus, Celluloid compounds, Calcium carbide,

Lime phosphate, Magnesium (powder), Aluminum (powder), Powder of metals 

other than magnesium and aluminum, Sodium hydrosulfite 

Potassium chlorate, Sodium chlorate, Ammonium chlorate, and other chlorate

Potassium perchlorate, Sodium perchlorate, Ammonium perchlorate, and other

perchlorate 

Potassium peroxide, Sodium peroxide, Barium peroxide, and other inorganic

peroxide 

Potassium nitrate, Sodium nitrate, Ammonium nitrate, and other nitrate 

Sodium chlorite and other chlorites 

OXIDIZING:

Calcium hypochlorite and other hypochlorites 

Ethyl ether, Gasoline, Acetaldehyde, Propylene chloride, Carbon disulfide, and 

other flammable substances having a flash point of lower than -30°C

Normal hexane, ethylene oxide, acetone, benzene, methyl ethyl ketone, and

other flammable substances having a flash point of -30°C or higher but lower

than 0°C

Methanol, Ethanol, Xylene, Pentyl acetate (amyl acetate), and other flammable 

substances having a flash point of 0°C or higher but lower than 30°C

INFLAMMABLE 

LIQUID:

Kerosene, Light oil (gas oil), Oil of turpentine, Isopentyl alcohol (isoamyl alcohol),

Acetic acid, and other flammable substances having a flash point of 30°C or 

higher but lower than 65°C

FLAMMABLE

GAS:

Hydrogen, Acetylene, Ethylene, Methane, Propane, Butane, and other flammable

substances which assume a gaseous state at 15°C and 1 atm 

(Source: Appendix Table 1 of Article 6 of the Industrial Safety and Health Order in Japan)

31 
Responsibility

Please follow the instructions in this document when using this unit. Yamato Scientific America

has no responsibility for the accidents or breakdown of device if it is used with a failure to 

comply. 

Never conduct what this document forbids. Unexpected accidents or breakdown may result in.

Note 

◆ The contents of this document may be changed in future without notice. 

◆ Any books with missing pages or disorderly binding may be replaced.

Instruction Manual for 

Vacuum Drying Oven 

Model ADP21/31 

Ver.3 May 12, 2004 

Yamato Scientific America Inc. 

385 Oyster Point Blvd Suite 8B, South San 

 Francisco, CA 94080 

 Tel:1-800-2YAMATO(292-6286) 

 http://www.yamato-usa.com

32