ACCUTEMP SERIES 

VACUUM DRYING OVENS 

USER’S MANUAL 

 

 

www.AcrossInternational.com 

AI NEW JERSEY 

111 DORSA AVE, LIVINGSTON NJ 07039 

888-988-0899 

SUPPORT@ACROSSINTERNATIONAL.COM 

AI NEVADA 

1197 GREG ST, SPARKS, NV 89431 

775-360-2332 

SUPPORT@ACROSSINTERNATIONAL.COM 

@AcrossIntl
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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PRECAUTIONS ..............................................................................................2 

1. INTRODUCTION .........................................................................................3 

2. SPECIFICTIONS ..........................................................................................4 

3. OVEN COMPONENTS ..................................................................................5 

4. PREPARATION ...........................................................................................8 

5. OVEN OPERATION .....................................................................................9 

6. AUTO TUNE (AT) CALIBRATION .................................................................10 

7. ADVANCED SETTINGS (FOR 1-SEGMENT CONTROLLER) .............................13 

8. MULTI-SEGMENT RAMP TEMPERATURE CONTROLLER OPERATION...........15 

9. TROUBLESHOOTING ................................................................................19 

10. MAINTENANCE .......................................................................................21 

11. ULTIMATE VACUUM LEVELS AT DIFFERENT ALTITUDES...........................22 

12. PRESSURE VS VAPORIZATION..................................................................23 

13. PARTS LIST.............................................................................................25 

14. SCHEMATICS AND CONTROLLER CONNECTION........................................26 

15. WARRANTY.............................................................................................29 

TABLE OF CONTENTS 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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Thank you for choosing our AccuTemp series vacuum drying oven. Please read this manual 

carefully before operating the unit. Keep this manual on-hand, so that it can be used by all 

operators of the unit. Across International is not responsible for any injury or damage 

caused by misuse. If the equipment is used in a manner not specified by Across 

International, the protection provided by the equipment may be compromised. 

PRECAUTIONS 

o IMPORTANT! NEVER LEAVE YOUR OVEN UNATTENDED WHILE OPERATING. Across 

International is not responsible for any loss of material inside of the oven. 

o THIS IS NOT AN EXPLOSION PROOF OVEN. THIS OVEN IS NOT SUITABLE FOR USE IN 

CLASS I, II, OR III LOCATIONS, AS DEFINED BY THE NATIONAL ELECTRICAL CODE, 

NFPA 70. 

o It is important to use vacuum grade tubing for all vacuum hookups. Other types of tubing may 

collapse and prevent complete evacuation. 

o The vacuum chamber should be thoroughly cleaned and disinfected prior to use. There are many 

commercially available disinfectants that are non-corrosive, non-abrasive, and suitable for use 

on stainless steel surfaces. Choose the one that will work best for your application. 

o Never clean the unit with flammable cleaners. Assure that all cleaning agents are completely 

evaporated and dried before reconnecting the unit to the power supply. 

o Do not try to heat flammable, combustible or explosive materials, or other materials that may 

release corrosive substances. 

o Do not heat sealed containers in the oven. The pressure differential under vacuum can could 

potentially cause the container to explode. 

o Avoid exposing the unit to vibrations or any corrosive/erosive gases. 

o Always wear thermal gloves and protective goggles during operation. 

o Always use the power cord that comes with the unit. Never modify the cable. 

o Keep oven away from any electromagnetic interference. Do not unplug the oven during normal 

operation. 

o Do NOT use the vacuum oven as a positive pressure vessel. 

o When vacuuming is complete, close the vacuum valve before turning off your vacuum pump. 

This will prevent pump oil from back flowing into the oven, if you are using an oil vane pump. 

o Consider conditions that may affect your oven’s ability to accurately control its temperatures. 

Examples include extreme heat from radiators, stoves, other ovens, autoclaves, etc. Avoid direct 

sun, fast-moving air currents, and heating/cooling ducts. 

o To ensure proper air circulation around the oven, allow a minimum of 10 inches between the oven 

and any walls or partitions. 

o A separate circuit for the oven and the pump is strongly recommended to prevent possible loss of 

product, either due to overloading or failure of other equipment on a shared circuit. 

o Returning shipments: Save the original shipping crate until you are sure your unit is consistently 

working properly. If for any reason you must return the unit, first contact AI for a return 

authorization (RMA). 

o It is strongly advisable to have at least two people lift or move all desktop models. 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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This ACCUTEMP DESKTOP series (0.9 and 1.9 cu ft) digital vacuum oven features an easy-to-clean 

stainless steel chamber with a large tempered glass safety window. Each unit comes standard with 

aluminum shelves, which provides excellent temperature uniformity inside the chamber. They also feature 

adjustable gas back fill capability with a needle valve and vent port. The low proportional gain temperature 

controller keeps your oven temperature within +/- 1°F accuracy, in either °F or °C. 

The ACCUTEMP SHELF-HEAT series (3.2, 7.5 and 16 cu ft) digital vacuum oven features a larger, 

production sized chamber with easy-to-clean stainless steel, as well as a large observation window with 

heavy duty 3/4" tempered safety glass. With our unique SHELF-HEAT technology, each shelf in these 

ovens comes with its own heat source, in-shelf temperature sensor and temperature controller. The result is 

perfect uniformity, accurate temperature, super-fast heating rates, minimum heat loss, and very low power 

consumption. 

Features 

o Dual layer observation window with tempered safety glass. 

o Radiant wall heating (0.9 and 1.9 cu ft models) provides optimal uniformity and conserves chamber 

space. 

o New SHELF-HEAT technology with in-shelf temperature sensors give you perfect uniformity, 

super-fast heating rates and very low power consumption (3.2, 7.5 & 16 cu ft models). 

o Easy-to-clean, heavy duty stainless steel interior for exceptional durability and ease of maintenance. 

o Force-adjustable latch and one-piece door sealing gasket maintains consistent vacuum levels. 

o Built-in check valve prevents vacuum oil back flow. 

o Built-in alarm alerts you when oven has been shut down by the safety circuitry, due to excessive 

variance in temperature. 

o Optional sliding and stackable shelves maximize your production scale. Many different types of 

shelving materials are available. 

Every one of our vacuum ovens goes through a 2-time, 24-hour vacuum leak test, and is quality controlled in 

New Jersey or Nevada, USA, before leaving our warehouses. 

For best performance and faster heating rates, perform an Auto-Tune before initial use. 

Instructions can be found in section 6 of this manual. 

1. INTRODUCTION 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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Model AccuTemp-09 AccuTemp-19 AccuTemp-32 AccuTemp-75 AccuTemp-75a AccuTemp-160 

Electrical requirements 110V or 220V 50/60Hz 1-PH 220V 50/60Hz 1-PH 

Chamber capacity 0.9 cubic foot 1.9 cubic foot 3.2 cubic foot 7.5 cubic foot 7.5 cubic foot 16 cubic foot 

Chamber dimensions 

(WxDxH) 12 x 12 x 11” 16 x 14 x 14” 18 x 18 x 18” 22 x 23 1⁄2 x 25” 22 x 23 1⁄2 x 25” 25 1⁄2 x 30 1⁄2 x 35 1⁄2” 

Chamber material 3mm thick stainless steel 

Output 1200 watts 1500 watts 1500 watts 1500 watts 1500 watts 3000 watts 

Warm-up time to 

100°F 60 minutes 60 minutes 35 minutes 45 minutes 50 minutes 55 minutes 

Shelf 

Maximum 4 

sliding shelves 

Maximum 5 

sliding shelves 

3 heated shelves, 

holds another 

maximum of 3 

stackable shelves 

3 heated shelves, 

holds another 

maximum of 6 

stackable shelves 

5 heated shelves, 

holds another 

maximum of 5 

stackable shelves 

6 heated shelves, 

holds another 

maximum of 6 

stackable shelves 

Distance between 

shelves 2 inches 2 inches 4 3⁄4 inches 7 inches 4 1⁄4 inches 5 inches 

Number of temperature 

controllers 1 1 3 3 5 6 

Observation window 1/2” tempered 

safety glass 

1/2” tempered 

safety glass 

5/8” tempered 

safety glass 

3/4” tempered 

safety glass 

3/4” tempered 

safety glass 

3/4” tempered safety 

glass 

Unit weight 90 Lb 140 Lb 280 Lb 400 Lb 430 Lb 710 Lb 

Shipping weight 150 Lb 200 Lb 350 Lb 500 Lb 530 Lb 940 Lb 

Unit dimensions 

(WxDxH) 24x20x18” 28x22x22” 30x24x29” 35x31x38” 35x31x38” 33x36x53” 

Shipping dimensions 

(WxDxH) 28x24x24” 32x27x28” 34x30x35” 38x35x43” 38x35x43” 43x40x60” 

Temperature range Ambient to 480°F in 0.1°F steps 

Ambient to 250°F in 

0.1°F steps 

Temperature controller Low proportional gain with LCD screen. Microcomputer-controlled automatic PID selection 

Temperature units Fahrenheit or Celsius 

Temperature accuracy +/- 2°F 

Temperature 

uniformity +/- 6% of set point (After target temperature fully stabilized) 

Dwelling timer range 1 to 9999 minutes 

Vacuum level Better than 500 microns/millitorrs 

Maximum vacuum 29.9 inches of mercury (may vary based on your local altitude) 

Vacuum gauge range 0 to 30 inches of mercury 

Door gasket material Silicone 

Vacuum connection KF25 flange 

Safety Built-in circuit breaker, over-heat protection 

2. SPECIFICATIONS 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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0.9 and 1.9 cubic foot models

3. OVEN COMPONENTS 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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3.2 cubic foot model
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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7.5a cubic foot model
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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4.1. Your oven should be placed on a sturdy platform that is approximately 30 inches off the ground, 

or the same distance your building code requires for a water heater. 

4.2. Best practices for vacuum operations: 

a. Place all shelves that you will use inside oven, make sure vent port, vacuum port are closed, and 

oven door is closed securely. 

b. Connect vacuum pump with KF25 stainless steel bellow, clamps and o-rings. 

c. Turn on your vacuum pump. 

d. Open vacuum port on the oven and watch the vacuum level on the vacuum gauge. 

e. When desired vacuum level is reached, close the vacuum port FIRST, and then turn off your 

vacuum pump. (It is a good idea to leave the pump on at all times during the heating process, and 

then for an additional 30 to 60 minutes afterwards, to allow the pump to clear out any moisture 

that may have been pulled into it during the vacuuming process.) 

4.3. Guidelines for using the vacuum oven 

a. Put your sample into the oven. Close the door securely, then close the vacuum release, open the 

vacuum valve, and turn on the power to the vacuum pump to start the purging process. When your 

vacuum level inside the oven is where you want it to be, close the vacuum valve first, then turn off 

the vacuum pump. 

b. Turn on the oven and set your target temperature. Temperature in the oven will start to rise and the 

heating indicator will blink. Usually, the oven enters into temperature-dwelling mode within 30 to 

120 minutes, depending on your target temperature. 

c. If your target temperature is low, you can set your temperature at two intervals to minimize 

temperature spikes. For example, if your target temperature is 100°F, the first target temperature 

value can be set to 90°F, and when temperature reaches that point, set the temperature one more 

time to 100°F. By doing so, temperature overshooting can be reduced or prevented and 

temperature dwelling state can be started as soon as possible. 

d. The length of drying time should be selected based on the humidity level of your sample. In case 

drying time is long and vacuum level reduces due to off-gassing, etc, it is necessary to purge the 

oven again to restore desired vacuum level. (Make sure your vacuum pump can work at your target 

temperature when doing this). 

e. After the drying process is done, turn off the oven, open the vacuum release valve, then open the 

door. It is possible that the sealing gasket may become stuck to the door glass, causing the door to 

not open easily. If this happens, wait a few minutes until the gasket restores itself before trying to 

open the door again. 

We recommend using our T series cold trap in between your oven and vacuum pump, to 

protect your pump from damage caused by the extraction of solvents or other gases. 

4. PREPARATION 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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[MAIN] mode: After the oven is first turned on, controller enters into [MAIN] (running) mode. 

[SET] mode: Hold and press “Set” button for 3 seconds in [MAIN] mode to enter into the [SET] (setting) 

mode. 

[AT] indicator: Light blinks when auto-tune is in progress. Blinking indicator stops when auto-tune is done. 

[ALM] indictor: Light turns solid if over-temperature alarm is triggered. Flashes if under-temperature alarm 

sounds. Turns off when oven is under normal operation. 

[HEAT] indicator: Turns on when oven is being heated. 

[RUN/STOP] indicators: Turns off when dwelling time is completed. 

5-1. Basic settings: Target temperature and dwelling time 

a. Plug in the power cable, switch on the circuit breaker in the back, and turn on the oven. 

b. Press the ‘Set’ button once. The controller will display “SP”. Now use “Shift”, “Decrease” or “Increase” 

button to set your target temperature. 

c. Press ‘Set’ again to confirm the temperature. The controller will display “ST”. Use “Shift”, “Decrease” 

or “Increase” button to set the dwelling time in minutes. You can set it to display in hours with the “Hn” 

setting. (The timer will start as soon as the actual temperature reaches target temperature.) If “ST” is set 

to zero, the oven will continue to run at the target temperature until it is turned off manually. 

 

d. Press ‘Set’ again to confirm all settings. 

e. When the dwelling time is complete, the controller will display “End” and buzz for 60 (or value in EST) 

seconds. It can be muted by pressing any button. 

 

f. Press and hold the “Dec/Rst” button for 3 seconds to restart oven operation. 

g. During heating, if the alarm is set and the actual temperature is over that limit, a buzzer will sound 

continuously and the “ALM” light will come on. Press any key to mute it. 

5. OVEN OPERATION 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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Prompt Name Description Range (factory value)

SP Target temperature Set target temperature in °F or °C. use code “FC” to set 

temperature unit.

SPL to SPH (see parameter table #2) 

ST Dwelling time 0 = continuous heating. Use code “Hn” to set timing unit 0-9999 (0) minutes or hours 

5.2. Finishing your process 

After purging and heating is done, turn off the main power switch. If you wish to fill your oven with inert gas, 

use the vent port (shown below) to connect to a nitrogen, argon, etc. source. Open the vent port and let the 

vacuum level restore to atmospheric pressure, then open the door and remove your samples (caution: surfaces 

may be hot!). 

5.3. Switching the temperature display between Fahrenheit (°F) and Celsius (°C) 

Under [MAIN] mode, press and hold the “Set” button for 3 seconds. The controller will display “Lc”, shown 

below. Enter 27 and press “Set” to access the “FC” (temperature display) setting screen, also shown below. 

Set “FC” to 0 to display the temperature in Celsius, or 1 for Fahrenheit. When done, press and hold “Set” for 

3 seconds to save and exit to [MAIN] mode. 

 (0001 = Fahrenheit °F)

 For optimal uniformity, allow 60 to 90 minutes for oven temperature to stabilize after target 

temperature is reached.

6.1. What is Auto Tune (AT)? 

Auto tune is a process of optimizing your oven’s performance. It helps increase heating rates, minimize 

temperature differences, and prevents overshooting. A set of optimal PID values will be saved 

automatically after AT is done. 

6.2. When should you perform an AT? 

a. If your target temperature is above 200 °F or higher, the first time you are using your oven. (If less 

than 200 oF, you can skip this process.) 

b. If you’ve recently changed or replaced any parts inside your oven. 

c. If you see a big temperature difference between controller display and actual oven temperature. 

6. AUTO TUNE (AT) CALIBRATION 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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6.3. Calibration by Auto-Tune (AT) 

 Follow the steps below to perform a standard Auto Tune: 

a. Under [MAIN] mode, press and hold the “Shift/AT” button for six seconds, until you see the screen below. 

 

b. Press the “Inc/BL” button and set AT to “on”, then press “Set” to confirm. The controller will display a 

flashing [AT] light, indicating that auto-tune is in progress. After a few cycles of fluctuation, auto-tune will 

complete and the [AT] light will turn off. This could take a few hours. The “Set” button is disabled during 

this period. 

c. If necessary, press and hold the “Shift/AT” button for six seconds during the auto-turn process to 

abort. The [AT] light will turn off. 

d. A new set of optimized PID values will be automatically saved for future use. 

e. Now set the target temperature. You are ready to use the oven. 

6.4. Calibration by formula 

Offset the temperature difference between temperature controller and your reference value manually. 

6.4.1. First, calculate the offset value using the formula on the next page (in blue). Press and hold “Set” button 

for 3 seconds; controller will display “Lc” as below. 

 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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6.4.2. Enter 3 and press “Set”. Continue to press “Set” until you see “PL”, as shown below. 

 

6.4.3. Use the formula below to calculate the offset value, then set PL to your calculated offset value. 

Offset value = (temperature measured by exterior thermocouple(s) – temperature displayed by controller [PV]) x 

1000 / temperature displayed by controller [PV] 

6.4.4. Press and hold “SET” for 3 seconds to confirm and return to [MAIN] mode. 

6.5. Calibration by adjusting PID manually (requires experience and practice) 

After an auto-tune, if you still feel that temperature is unstable, you can manually adjust the PID values. PID 

adjustment is very useful for you to control the oven temperature in an acceptable range, but requires some 

practice and patience. 

a. “P” represents proportion adjustment. Increasing “P” reduces temperature overshooting, while decreasing 

“P” allows for a faster heating rate. (You may need to try this step a few times before you get the best result). 

b. “I” represents integral time. Increase “I” to lower temperature fluctuation. It can be used to eliminate the 

steady state error after the system enters a steady state by correctly setting “P”. In other words, “I” is often 

used after “P”. Give “I” a big value before decreasing “P” a little, in order to get to a steady state, and then 

decrease I to eliminate errors under the steady state. Check if the PV is in your desired range. Continue to 

try to change “P” and “I” to get the best result. 

c. “D” represents differential time, which can overcome the unstable and oscillating state. Adjust “D” to 

reduce temperature overshooting. It is usually set after the “I” adjustment. Firstly, set “D” to 0, then 

gradually increase it to check if you have an acceptable result (In this process, “P” and “I” may also be 

changed). “D” is usually set anywhere between 1/5 to 1/4 of the value of “I”. 

Every oven has been calibrated and tested before leaving our factory. Under normal circumstances, 

self-calibration is not necessary. However, if the temperature requirements are very strict, or if target 

temperature is set around the upper or lower limits of the oven temperature range, the measured temperature 

might not be accurate against the actual temperature in the oven. 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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Under [MAIN] mode, press and hold the “Set” button for 3 seconds. The controller will display “Lc” as shown on the 

next page. Enter 3, 9, 27 or 567 and press “Set” to access the advanced setting tables on the following page Press and 

hold “Set” for 3 seconds to save and exit to [MAIN] mode. 

 

Table 1 

Prompt Name Description Range (factory value) 

Lc: Pass key When Lc = 3, controller enters into the menu below 3, 9, 27, 567 (0) 

ALH: Over-temp 

alarm If SV>(SP+ALH), ALM light comes on, buzzer sounds, and oven stops heating. 0-180 (36) under °F mode 

0-100 (20) under °C mode 

ALL: Under-temp 

alarm If SV<(SP-ALL), ALM light will flash and buzzer will sound. Under-temp 

is not active if ALL is set to 0. 

0-180 (0) under °F mode 

0-100 (0) under °C mode 

P: Proportional Increasing P may reduce temperature overshooting. Decrease P to allow 

for a faster heating rate. 1-540 (60) under °F mode 

0.1-300 (60) under °C mode 

I: Integral Increase I to lower temperature fluctuation. 1-2000 (900) seconds 

d: Differential Adjusted to reduce temperature overshooting. Usually set to 1/5 to 1/4 of “I” value. 0-1000 (450) seconds 

T: Control cycle Heating control cycle in seconds. 1-60 (20) seconds 

Pb: Ambient 

adjustment Corrects the difference between ambient temperature and what the 

controller is reading. 

Pb = Temperature measured by the exterior thermocouple(s), vs. the 

temperature displayed by controller. 

-90 to 90 (0) under °F mode 

-50 to 50 (0) under °C mode 

PL: Hot adjustment Offset the temperature difference between the controller and actual 

reading inside the oven. (Use the calibration formula in section 6.4) 

-999 to 999 (0) 

Addr Communication address. 1-32 (1) 

Loc: Lock Temperature and time setting: 0 = enabled 1 = disabled 0-1 (0) 

7. ADVANCED SETTING (FOR 1-SEGMENT CONTROLLER) 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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Table 2 (Do NOT modify unless instructed by an AI technician.)

Prompt Name Description Range (factory value)

Lc: Pass key When Lc = 9, controller enters into the menu below 3, 9, 27, 567 (0) 

ndA: Temp alarm mode 0: with over-temp alarm only 

1: with over-temp alarm and under-temp alarm 

0-1 (0) 

ndT: Timer mode 0: no timer function 

1: with timer function, SV window will display dwelling time after 

oven temperature reaches target temperature. 

2: with timer function, SV window will always display dwelling 

time. 

0-2 (1) 

Hn: Timer unit 0: displays timer in minutes 1: displays timer in hours 0-1 (0) 

SPd: Constant 

temperature deviation 

When PV > SV – SPd, oven is under constant temperature state 0.1-180 (0.9) under °F mode 

0.1-100 (0.5) under °C mode 

SPT: Constant temp 

state buzzing time 

Set buzzing time in seconds when oven enters into constant temp 

state. Buzzer will sound constantly if SPT is set to 9999. 

0-9999 (0) seconds 

EST: Dwelling time up 

buzzing time 

Set buzzing time in seconds when the dwelling time is up. Buzzer 

will sound constantly if EST is set to 9999. 

0-9999 (60) seconds 

EH: Continue to heat 

after dwelling time ends 

0: Turns off heating when dwelling time is over 1: Continues to keep 

the oven at constant temperature, even after dwelling time is over. 

0-1 (0) 

ndo: Output mode 0: Output after dwelling time over. 1: Output after over-temp 

2: Output when oven enters into constant temperature state. 

0-2 (0) 

SPL: Min temperature Set minimum temperature the controller can go to. -58 to 122 (32) under °F mode 

-50 to 50 (0) under °C mode 

SPH: Max temperature Set maximum temperature the controller can go to. 32-752 (572) under °F mode 

SPL to 400 (300) under °C mode 

Table 3 

Prompt Name Description Range (factory value) 

Lc: Pass key When Lc = 27, controller enters into the menu below 3, 9, 27, 567 (0) 

FC: Temperature 

display mode 

0: Celsius 1: Fahrenheit 0-1 (0) 

Table 4 

Prompt Name Description Range (factory value) 

Lc: Pass key When Lc = 567, controller enters into the menu below 3, 9, 27, 567 (0) 

rST: Factory reset 0: Do not reset to factory settings 1: Reset to factory settings 0-1 (0) 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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8.1. Controller components 

8. MULTI-SEGMENT RAMP TEMPERATURE CONTROLLER OPERATION
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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Prompt Name Description Range 

SV Target temperature Target temperature for each segment 0 to max temp (SPH) 

PV Current temperature Current temperature in the oven 

SP Segments SP00 displays current temperature and is non-editable SP00 to SP30 

St Time St00: 0-9999, St01-31: -002 to 9999 St01 to St31

8.2. Operation 

1) When the controller is switched on, display windows show “Pt” and the value of temperature range for 3 

seconds, then it starts running. 

2) “◄” button: In the setting mode, click the button to shift the digit. 

 3) “▼” button: In the setting mode, click the button to reduce the set value. Press and hold the button to reduce the 

value continuously. 

 4) ”▲” button: In the setting status, click the button to increase the set value. Press and hold the button to increase the 

value continuously. It can also turn the backlight on or off. 

 5) In the setting mode, if the controller is idle for more than one minute, it will automatically return to normal mode. 

 6) Temperature and time setting 

 Press the “SET” button. The controller will display: SP00; St01, SP01; St02, SP02 ... St30, SP30; St31”. 

 SP00 is the current measured temperature and cannot be modified. 

 If “St > 0”, this refers to the time the oven takes to get to target temperature of a segment. 

 If “St = 0”, the oven will heat to the target temperature of that segment in shortest period of time. 

 If “St = -1”, the oven will heat to target temperature and stay there until shut off manually. 

 If “St = -2”, the oven will shut off automatically when target temperature is reached. 

 During the setup process, press and hold the “SET” button for 3 seconds to exit. The settings will be saved 

automatically. 

 In the setup process, first press the “◄”, then click the “SET” button to view on a set value. 

 EXAMPLE: 

1. Heat oven to 80 degrees, from room temperature, in 20 minutes. 

2. Remain at 80 degrees for 30 minutes. 

3. Raise the heat to 120 degrees in 40 minutes. 

4. Stay for 30 minutes at the 120 degrees. 

5. Turn off the oven. 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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 STEPS: 

 SP00 (current measured temperature, cannot be modified) 

 St01 = 20, SP01 = 80 

 St02 = 30, SP02 = 80 

St03 = 40, SP03 = 120 

 St04 = 30, SP04 = 120 

 St05 = -002 

 7) Press and hold the “R/S” button for 2 seconds until you see “RUN” come on, then release the button to start the 

heating cycles. (The circular arrow icon will flash and the sun icon to the left of “HEAT” will come on and off 

periodically). 

 8) During the heating process, the PV will display the current temperature and SV will display the amount of time that 

has elapsed. 

 9) During heating process, press the “Inquire” button once. The controller will display the current segment number. 

Press the “Inquire” button again, and the PV will display the timed setting of the segment. The SV will display time 

elapsed. 

 10) To stop the oven manually, press and hold the “R/S” button for 2 seconds, until you see the “STOP” light come on, 

then release the button. 

 11) When the over-temperature alarm is triggered, a buzzer will beep continuously. The "ALM" light will come on. 

Press any button to stop the buzzer. 

 12) If PV displays “----”, the thermocouple or temperature controller may be faulty. Please check the 

thermocouple and wiring, or replace your temperature controller.

 8.3. Multi-segment controller Auto-Tune 

Use the auto-tuning function for optimal temperature control. During auto-tuning, the “AT” indicator will flash. 

After auto-tuning is done, the “AT” stops flashing. The parameters and values will be saved automatically. 

In stop mode, press and hold the “AT” button for 5 seconds. The controller will display “AT”. If “AT” = 0, the 

controller will quit and return to normal display. If “AT” = 1, the controller displays “AtSP”. After adjusting the 

“AtSP” value, press the “SET” button again to start auto-tuning. 

During the auto-tuning process, press the hold “AT” button for 5 seconds to quit manually. 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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8.4. Advanced settings 

Press and hold the “SET” button for 5 seconds. The controller will display “Lc”. Enter your pass key and then 

press “SET” to enable the advanced setting menus. Press and hold the “SET” button for 5 seconds to quit. 

Prompt Name Description Range 

(factory value) 

Lc Pass key When Lc = 3, the controller enters into the menu 

below 0 

AL Alarm 

When temperature is beyond “SP+AL”, the ALM 

indicator will turn on. The buzzer will sound and 

the oven will turn off. 

0.0 to 100.0Ԩ (20.0) 

T Control cycle The control cycle of temperature control. 1 to 60s (5) 

P Proportional 

Increasing P may reduce temperature 

overshooting. Decrease P to allow faster heating 

rates. 

1.0 to max temp set in 

next table or SPH (35.0) 

I Integral Increase I to lower temperature fluctuation. 1 to 1000s (200) 

d Differential Adjusted to reduce temperature overshooting. 

Usually set to 1/5 - 1/4 of the value of I. 0 to 1000s (100) 

Pb Ambient 

adjustment 

Corrects the difference between ambient 

temperature and what the controller is reading.

Pb = Temperature measured by the exterior 

thermocouple(s), vs. the temperature displayed by 

controller. 

-12.0 to 12.0Ԩ (0.0) 

PK Hot 

adjustment 

Adjust when the temperature of the 

controller is different from the actual temperature 

inside of the oven. 

PK = (actual value - target value) x 1000 / 

maximum controller temperature 

-999 to 999 (0) 

Prompt Name Description Range 

(factory value) 

Lc Pass key When Lc = 9, the controller enters into the menu 

below. 0 

Pon Not used. 0 to 2 (0) 

Stn Not used. 0 to 0 (0) 

odr Not used. 0 to 5 (0) 

Addr Communication address. 1 to 16 (1) 

SPH Max Temp 

Sets the maximum temperature the controller can 

go to (Do NOT modify. Setting max temperature 

too high could permanently damage your oven!) 

0 400 (300) 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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9.1. Issue: Oven temperature is consistently overshooting 

Solution: It is normal for temperatures to overshoot in a vacuum oven, prior to stabilization. A generally 

accepted range of temperature overshoot within 2 to 5 degrees. Once stable, the oven should maintain 

within the specified uniformity. If the oven is overshooting and remains too hot, check the following: 

a) Temperature controller set drastically higher than where it was calibrated. 

b) The oven is not under vacuum. Always run the oven under vacuum. 

c) The oven needs to be re-calibrated under Auto Tune. 

9.2. Issue: Temperature displayed and reference value are different 

Solution 1: Because there is no air in the chamber, the heat must radiate and conduct across the shelves 

and through the chamber, it takes a lot of time for the temperature to stabilize. It is common for shelves to 

be much cooler than the walls for a number of hours during the warm up process. When using an 

independent thermocouple to verify temperature, pay attention to the following: 

 Always have the unit under vacuum when checking temperature. 

 Allow time for the oven to stabilize. We recommend anywhere from 1 to 4 hours. 

 Attach the probes to the shelves with heat-resistant tape. 

 The reading should be within the uniformity tolerance in the specifications. It might not match 

exactly, but it should be very close. 

 If the shelves run cooler than you would like, you can use the temperature setting to increase the heat. 

Turn the oven up until the parts on the shelves are at your desired temperature. 

Solution 2: Offset the temperature differences manually in the advanced settings by using the 

“Calibration by Formula” process, described in section 6.4. 

9.3. Issue: Oven cannot hold vacuum properly 

Solution: Before calling AI for technical support, please check the following: 

 Is the vacuum port open, the vent port closed, and pump connected properly to the vacuum port? 

 Check the door’s sealing gasket and make sure it is clean, well seated, and has no splits, cracks, 

flattened, or melted spots, or any other defects. 

 Check the door alignment. When you close the door, is it making good contact with the gasket all the 

way around? When in doubt, use a little vacuum grease on the door gasket, then shut the door. Did the 

grease transfer all the way around the gasket to the glass when opened? If not, realign the door. 

9.4. Issue: Oven vacuum gauge cannot get to ultimate 30 inches of mercury vacuum 

Solution: Make sure your vacuum pump is right size for your oven, and the pump is getting the right 

amount of power. Check if there is a large amount of off-gassing coming from the samples, and that the 

door is sealed properly. Your altitude in relation to sea level is also a big factor. Please refer to section 11.

9. TROUBLESHOOTING 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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Issue Reason Solution 

No power 

Oven is turned off. Check circuit breaker and turn on oven. Make 

sure oven is getting enough power to turn on.

Broken power cord or loose plug. Change or secure the power cord. 

Circuit breaker is off Turn on circuit breaker, located on back of oven. 

PV window displaying 

“-----”, “LLL.L” or 

“HHH.H” 

Faulty temperature sensor or loose connection Check connection or change temperature sensor 

Faulty temperature controller 

If the temperature sensor is OK and connection is 

good, replace the temperature controller. 

Unit failed to heat 

Dwelling time is over Reset dwelling time and restart the oven. 

Loose connection on temp controller Check and make sure all connections are secure. 

Faulty controller Replace temperature controller. 

Faulty heating element Replace heating elements. 

Parameter error Reset all parameters to factory setting using 

parameter table #4. 

Temperature control 

failure 

Loose connection on temperature sensor Check all connections. 

Faulty controller Replace temperature controller. 

Target temperature too low Set a higher target temperature. 

Abnormal alarming for 

oven temperature Faulty controller Replace temperature controller. 

Large temperature 

difference between oven 

display (PV) and 

temperature measured 

by yourself with a 

thermometer placed 

inside of the oven. 

Temperature and condition of your current 

working environment is different than the 

environment your oven was initially calibrated 

Perform an Auto-Turn (AT) as described in 

section 6.3 above 

Oven was not turned on long enough 

Perform temperature measurement 30 minutes 

after oven reaches its target temperature, this 

allows temperature inside the oven to stabilize. 

Your temperature sensors were placed incorrectly Place temperature sensors in the middle of the 

oven shelves. 

Your infrared gun is not used correctly or not 

properly calibrated 

Make sure your infrared gun is calibrated 

correctly. Shooting an infrared gun across the 

oven window glass may give you incorrect 

readings. Try using a regular thermometer 

instead. 

If solutions above do not fix the difference Perform a “Calibration by formula” as described 

in section 6.4 above 

Parameter error Reset all parameters to factory setting using 

parameter table #4 in section 7 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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10.1. Oil/rotary vane pumps: These pumps will require oil changes. The frequency of the changes will 

depend on how often the pump is used, and for how long. Watch for the oil to become cloudy, darkened, 

or milky. As soon as the color becomes varied, it’s time to change the oil. We recommend ultra-grade 19 

vacuum pump oil. Depending on how much water or gunk is being pulled off your product and thru the 

pump, it may be a good time to also replace the exhaust oil mist filter. 

10.2. Dry/scroll pumps: These pumps will require “tip seal” changes. Most pump manufacturers 

recommend every 9,000 hours of use, or at least once per year. Degradation of vacuum levels or poor 

pump performance may mean it’s time for a tip seal change. AI carries various service kits and tip seal 

kits for the pumps that we offer. 

10.3. Gasket inspection: The door gasket is considered a “high-wear” item. Heat and pressure will 

eventually cause the gasket to need replacing. If you notice a loss of vacuum, the gasket is the first item 

to check. It is always a good idea to have a spare gasket on hand, to minimize down time. 

10.4. Keep the oven clean at all times. Clean the glass, sealing gasket, and chamber after each use. 

10.5. The oven must be unplugged under the following circumstances: Repairing, moving the oven, or 

when the oven is not being used for a long time. 

10.6. If the oven needs to be placed into storage for a long time, be certain that the chamber is dry, the 

latch to the door closed, and the power cord has been disconnected. Cover the oven entirely to keep it 

away from dust and moisture.

10. MAINTENANCE 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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There are many ways to measure vacuum levels. AI’s vacuum ovens use both mechanical vacuum gauges 

(standard, read in inHg) and digital vacuum gauges (optional, reads in inHg, mmHg, psi, etc.). The 

achievable ultimate vacuum level will depend on your altitude. Please use table below for reference. 

11. ULTIMATE VACUUM LEVELS AT DIFFERENT ALTITUDES 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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Vacuum evaporation is the process of causing the pressure in a vacuum oven to be reduced below the vapor 

pressure of the liquid, causing the liquid to evaporate at a lower temperature than normal. 

Liquids may change to a vapor at temperatures below their boiling points through the process of evaporation. 

Evaporation is a surface phenomenon in which molecules located near the liquid's edge, not contained by enough 

liquid pressure on that side, escape into the surroundings as vapor. On the other hand, boiling is a process in 

which molecules anywhere in the liquid escape, resulting in the formation of vapor bubbles within the liquid. 

The vacuum evaporation treatment process consists of reducing the interior pressure of the vacuum oven below 

atmospheric pressure. This reduces the boiling point of the liquid to be evaporated, thereby reducing the heat 

necessary/eliminated in both the boiling and condensation processes. In addition, there are other technical 

advantages such as the ability to distill other liquids with high boiling points and avoiding the decomposition of 

substances that are sensitive to temperature, etc. 

The boiling point of a substance is the temperature at which the vapor pressure of the liquid equals the pressure 

surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the 

surrounding environmental pressure. A liquid in a partial vacuum has a lower boiling point than when that liquid 

is at atmospheric pressure. A liquid at high pressure has a higher boiling point than when that liquid is at 

atmospheric pressure. 

The normal boiling point (also called the atmospheric boiling point or the atmospheric pressure boiling point) of 

a liquid is the special case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea 

level, 1 atmosphere. At that temperature, the vapor pressure of the liquid becomes sufficient to overcome 

atmospheric pressure and allow bubbles of vapor to form inside the bulk of the liquid. The standard boiling point 

has been defined by IUPAC since 1982 as the temperature at which boiling occurs under a pressure of 1 bar. 

12. PRESSURE VS VAPORIZATION 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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Standard package 

Part description Quantity Part image

 AccuTemp series vacuum oven 1 pc 

 

 Aluminum shelf (for 0.9 and 1.9 models only) 4-5 pcs 

 User's manual 1 pc 

Parts and accessories 

Part description Part image

 Stone shelf 

 Vacuum oven door sealing gasket 

 Solvent proof digital vacuum gauge read in multiply units 

 1200 lbs heavy duty all welded steel mobile cart 

 T series cold trap for safe vacuum operations 

 Oil filled or oil free vacuum pumps 

 

 vacuum pump service kits 

 

 KF quick clamps and centering ring 

 Exhaust mist filters and filter elements 

 

 Food grade silicone or stainless steel vacuum tubing 

13. PARTS LIST 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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14. SCHEMATICS AND CONTROLLER CONNECTION 
ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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ACCUTEMP SERIES 480°F VACUUM DRYING OVEN USER’S MANUAL 

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Across International warrants for the original user of this product in the U.S.A., only that this product will be free 

from defects in material and workmanship for a period of one to two years (depending on which model the user 

has) from the date of delivery to the original user – the “Warranty Period”. 

During the Warranty Period, Across International, at its election and expense, will repair or replace the product or 

parts that are proven to manufacturer’s satisfaction to be defective, or at manufacturer’s option, refund the price 

or credit (against the price of future purchases of the product) the price of any products that are proven to 

manufacturer’s satisfaction to be defective. 

This warranty does not include any labor charges if outside of the U.S.A. This warranty does not cover any 

damage due to accident, misuse, negligence, or abnormal use. 

Use of Across International’s product in a system that includes components not manufactured by Across 

International is not covered by this warranty. 

This warranty is void in the event that repairs are made by anyone other than Across International without prior 

authorization from Across International. 

Any alteration or removal of the serial number on Across International’s products will void this warranty. Under 

no circumstances will Across International be liable for indirect, incidental, consequential, or special damages. 

The terms of this warranty are governed by the laws of the states of New Jersey and Nevada without regards to 

the principles of conflicts of laws thereof. If any provision of this limited warranty is held to be unenforceable by 

any court of competent jurisdiction, the remainder of this limited warranty will remain in full force and effect. 

This warranty is in lieu of and excludes all other warranties or obligations, either express or implied. Across 

International expressly disclaims all implied warranties, including without limitation, the warranties of 

merchantability and fitness for a particular purpose. 

After the warranty period, Across International will continue to provide support and spare parts at a reasonable 

cost. 

15. WARRANTY 

AI NEW JERSEY 

111 DORSA AVE, LIVINGSTON NJ 07039 

888-988-0899 

SUPPORT@ACROSSINTERNATIONAL.COM 

AI NEVADA 

1197 GREG ST, SPARKS, NV 89431 

775-360-2332 

SUPPORT@ACROSSINTERNATIONAL.COM