High Temperature Vacuum Tube Furnace 

GSL-1100 

Operational Manual

MTI Corporation

860 South 19th Street, Richmond, CA 94804, USA 

Tel: 510-525-3070 Fax: 510-525-4705 

E-mail: info@mtixtl.com Web site: www.mtixtl.com
Content

Introduction .................................................................................................... 3 

Technical Specifications................................................................................. 4 

Furnace Structure ...................................................................................... 4 

Operating environment ............................................................................. 4 

Instrument features.................................................................................... 4 

Operation ........................................................................................................ 5 

Tube and flange installations .................................................................... 5 

General Operation ..................................................................................... 5 

Temperature Controller Instruction........................................................... 6 

Temperature Controller Setting................................................................. 7 

Temperature Segment Setting ................................................................... 7 

Illustration of Temperature Segment Setting ............................................ 8 

Run the program...................................................................................... 10 

Temperature Controller Parameters ............................................................. 10 

Introduction ............................................................................................. 10 

Parameter Function ................................................................................. 10 

Parameter Setting .................................................................................... 10 

Troubleshooting for typical Problems............................................................ 6 

Thank you for purchasing MTI’s products, please read this manual before using the furnace, MTI has no responsibility 

for any damage caused by customer’s misuse. 

Notice: The specification data may be different from the data on our website because we keep upgrading the products, 

if any confusion, please visit MTI’s website at www.mtixtl.com for the latest data.
Introduction 

GSL-1100 series high temperature vacuum tube furnace is a compact designed for heating 

samples up to 1100 0C. Stainless steel vacuum flange with valve, vacuum gauge and quartz 

tube are included for immediate use. Built in precision temperature controller is able to 

program the heating rate, dwell time and cooling rate up to 30 segments. The furnace can be 

set up in both vertical and horizontal position to meet various applications such as firing 

sample, VSL and CVD. It is an excellent furnace for annealing, diffusing and sintering sample 

in various atmospheres. 

 
Operating Voltage: 110V AC±10

Technical Specifications 

Furnace Structure

Operating environment 

The operating environment information in the following table may be helpful if you plan to safely 

operate the instrument: 

 The construction request a dry, hard and flat surface; 

 The instrument shall be kept indoor with nice ventilation and avoided direct sunlight; 

 Operating temperature: 50 0C~350 0C; 

 Relative humidity (noncondensing): 10%~85%; 

 Dust-free. 

WARNING: To reduce the possibility of heat-related injuries or of overheating the instrument, 

do not place the instrument too close to the side wall or obstruct the air vents. Keep the instrument at 

least 1 meter in distance from the side wall.

Instrument features 

Power:1200W 

% Single Phase (16Amp air breaker required);

Operating Current: 5 Amp 

Single Phase, 50/60 Hz 

Pressure Gauge Quartz Tube Flange 

Gas Outlet

Temperature Controller 

Flange

Gas Inlet 

Working Run 

Indicator 

Stop 
Overall Dimensions D x H x W (inch): 10" x 15" x 16" (26 x38 x40 cm); 

304 stainless steel chamber; 

Operating Temp Range C: 200 0C ~1100 0C 

Temperature accuracy: +/- 1 0C; 

Suggested Normal Heating Rate: ≤10 0C /min 

Max. Heating Rate: ≤ 30 0C /min; 

Constant Temperature zone: 3.1" ( 80 mm); 

Temperature control: 30 segments programmable digital controller with PID function and 

overheated and overloaded protection; 

Vacuum Level: 1.0×10-3 Pa; 

Heating Elements: Fe-Cr-Al Alloy doped by Mo; ; 

Shipping Dimension: 21"x23"x25"(530 x 590 x 640mm);

Net weight (lb): 40 lbs; 

Warranty: One Year limited, not included quartz tub

e. 

Operation 

Tube and flange installations 

Once you received MTI furnace, please follow these steps to set up the furnace. 

Open the box; check out if the instrument and the accessories are well kept during the 

shipping. 

The instrument shall be kept indoor with nice ventilation; 

Slightly insert the quartz tube from one side; 

Insert the foam block and seal the tube at both ends with flanges. 

General Operation 

Place the test sample inside the tube, slightly insert the foam block and then seal both end 

of the tube with flanges. 

If you are going to set up the Vacuum/Gas Flow system with the furnace, please properly 

set the vacuum level / flowing rate when you need to purge and charge the inert gas into the 

tube. It is highly recommended to apply vacuum grease on the flange joint, please visit: 

http://www.mtixtl.com/furnaceaccessories.aspx for more information. 

 
Properly connect to the power supply and make sure it is well grounded; 

Power on the instrument by pressing “Run” button and you will see the control panel start 

to blink. 

Please refer to the following part “Temperature Controller Instruction” for how to set the 

temperature curve. 

NOTE:Once you finish the set up, we strongly recommend our customer FIRSTLY reading the 

handbook and then following the instructions of attached “QUICK TEST” inside the package to 

perform a quick test to check the heating condition of the furnace. 

CAUTION: To reduce the risk of electric shock or damage to your instrument during your 

quick test, observe these practices:

 The outer plate of the instrument must be grounded properly, for safety of operation; 

 The instrument shall be kept indoor with nice ventilation; 

 To reduce potential safety issues, do not place flammable and explosive materials around the 

instrument; 

 No explosion-proof, do not put any flammable and explosive materials into the chamber. 

Temperature Controller Instruction 

MTI provide two kinds of temperature controller with same function: 

Here, we will 

introduce the left one: 

Furnace Temp. 

(PV)

Setting Temp. 

(SV)

Increase button

(END)

Decrease button 

(RUN/PE)

Program setting/Left 

Shift/Auto-tune 

(AT/PROTA/M)

Parameter setting/Start the Program, 

view the time running (SET PAR)

Function 

Indicating
Temperature Controller Setting

Startup state 

When start the device, the meter type and program version will display for a few seconds, and then 

enter the normal state. Blinking “End” indicates the program is in stop state. 

Meter type & Program version Normal state 

Displaying switch 

a. In the “normal state” or “program running state”, press “SET” key for 1 second 

to switch to “executing program segment” (Set executing segment or display 

the ongoing temperature segment).

b. Press “SET” key again for 1 second to switch to “running time state” (Display the 

total running time PV xxxx min. and the elapsed time SV xxxx min.) 

c. Press “SET” key again for 1 second to back to “normal state”.

Temperature Segment Setting 

LTDE programmable smart instrumentation auto-controller allows you to set the temperature profile 

up to 30 segments. To process this function, follow these steps: 

Power on the furnace, blinking “End” on the SV window indicates the Normal State; 

Press “←” once to display “C01” on PV window; 

Set initial temperature to 0 oC by using Keystrokes :“←”, “↑” or “↓”; 

Press “Set” to display “t01” on PV window; 

Set heat-up time (Usually beyond 30 minutes for this segment in case of temperature 

overshooting) from initial temperature to target temperature by using Keystrokes :“←”, “↑” or 

“↓”; 
Press “Set” to display “C02” on PV window; Set the actual working temperature for the second 

segment by using Keystrokes :“←”, “↑” or “↓”; 

Press “Set” to display “t02” on PV window; Set heat-up time from initial temperature to target 

temperature by using Keystrokes :“←”, “↑” or “↓”; 

Press “Set” to display “C03” on PV window, Set the actual working temperature for the third 

segment; 

Press “Set” to display “t03” on PV window; Set heat-up time from initial temperature to target 

temperature; 

Press “Set” to display “C04” on PV window, Set the actual working temperature for the fourth 

segment; 

Press “Set” to display “t04” on PV window, Use Keystrokes :“←”, “↑” or “↓” to set duration 

for “C04”; 

By pressing “Set”, you can get into the following segments 

(C05&t05...C06&t06...C07&t07...) for temperature and time setting; 

Press “Set” to display “Cxx” on PV window (xx could be any values among 01~30); 

Press“←”, “↑” or “↓” to set “-121” in the last segment in order to shut down the furnace;
Illustration of Temperature Segment Setting 

Setting Example: 

 

According to figure I above, all segments was recorded in the following: 

Prompt Input Data Description 

C01 0 Initial Temperature 

T01 45 Heat-up time 45 minutes from 0-450 oC in the first segment 

C02 450 Target temperature of the first heat-up stage 

T02 20 Heat-up time 20 minutes from 450-500 oC in the second segment 

C03 500 Target temperature of the second heat-up stage 

T03 40 Keep 40 minutes at 500 oC 

C04 500 Constant temperature of the third stage 

T04 30 Heat-up time 30 minutes from 500-1000oC in the fourth segment 

C05 1000 Target temperature of the fourth heat-up stage 

T05 25 Keep 25 minutes at 1000oC 

C06 1000 Constant temperature of the fourth stage 

T06 20 Cooling time 20 minutes from 1000 to 800oC 

C07 800 Target temperature of the fifth heat-up stage 

T07 25 Keep 25 minutes at 800oC 

C08 800 Constant temperature of the sixth stage 

T08 -121 Program end, Out-put power off. Furnace cooling down naturally.

(t08 = -121 is an order to stop running) 
Run the program 

When temperature program set up ready, wait until “End” shows on SV window again, then 

press “↓”and hold for two seconds to display “Run” on SV window; 

Furnace will run automatically segment by segment according to the program setting; 

PV window displays increasing temperature at this moment; 

Hold the program 

If you need to hold the furnace at certain temperature when the program is running, press “↓” 

for 2 sec to hold the program and again press it to continue. 

Stop the program 

You can stop the program either from running or hold state by pressing “↑” for 2 seconds. 

Attention: 

 When finish all the segments you need, please end the last segment with -121; 

 It is not suggested to modify any parameters during the execution if he or she is not familiar 

with the furnace operation. If there is a must, please first stop the program. 

Temperature Controller Parameters 

Introduction 

Parameter Utility Range Unit/Notice Default 

Value 

Int Enhance Integral 

function 1-9999 

Pro Enhance Proportion 

function 1-9999 

Lt Limit time factor 1-2000 Second 

Crt Control period and 

auto-tune determining 1~8 

Cont Control type setting 3,2 3 

Ploc Lock the setting 0 1008 to unlock 0 

Parameter Function 

Int (Integral effect) 

Int is related to the system sustainment, take temperature for example, the larger, the more stable the 

system is. Like integral time of PID calibration, this parameter is mainly in charge of the integral 

work during the adjustment process, for instance, the smaller the Int is set, the stronger the system 

integral effect is, vice versa. When Int=0, the system will cancel integral and intelligent adjustment. 
Pro (Proportion effect) 

Pro is used for adjusting proportion and differential effect. The larger Pro is, the smaller proportion 

effect is, which means both adjustment and differential effect are enhanced to get sensitive ability to 

the temperature change, vise versa. 

Lt (Delay time coefficient) 

Lt is used to determine tradeoff of the proportion and differential. When it is small, proportion is 

strong and differential is weak, vise versa. If Lt is no more than the twice of Crt (will mention below), 

differential effect is off. 

Note: The three parameters discussed above should be adjusted after “auto-tune”. 

Crt (Period control and auto-tune determination) 

Crt is applied for adjusting the calculation cycle (unit is second), which makes critical impact on the 

system adjustment and of course, if it is set properly, we can better solve the temperature 

overshooting and system oscillating. Please remember to set this value before auto-tune since Crt may 

give a direct effect on it. Generally, set Crt in the range of 1~8 if main circuit adopts solid relay or 

controllable silicon unit; more than 8 if main circuit uses alternative current contactor; if Cont=0, set 

it as 0. 

Also, this parameter determines result of auto-tune: if it is revised after auto-auto, the auto-tune fails, 

please revise the value manually and restart auto-tune. 

Cont (Controlling type) 

When Cont=2, system starts auto-tune function to work out the value for Int, Pro and Lt, and then 

system will go to 3.When CtrL=3, adopts advanced AI adjustment, after auto-tune, the system goes to 

this setting mode, note that you can not startup auto-tune function from the controller panel, for a 
protection of repeating auto-tune, when you need a re-auto-tune, please set it as 2. 

Actually, “auto-tone” function could produce exact parameters for a general use. However, nobody 

could decide an absolutely stable electronic specification of each heating material (like resistance 

may vary because of temperature or time going by) or the difference between the temperature heating 

segments. 

Hence, the “auto-tune” may be not ideal. If so, you can manually modify Int, Pro and Lt 

PLOC:

Function lock, no need to revise if general use. 

Parameter Setting 

In the “normal state”, press “SET” key for 2 seconds, you will see parameter “Int” pops up and 

press “←”, “↑” or “↓” to modify the parameter. 

Press “SET” key for 1 second to go to next parameter and press “←”+“↓” for 1 seconds to back 

to preceding parameter. 

Press “←” and then press “SET” key to back up to “normal state”. Without any operation on the 

keys for about 30 minutes, the meter will automatically exit from “parameter setting state”. 
Troubleshooting for typical Problems 

Troubleshooting resources 

 Refer to “Quick troubleshooting”, the next section in this chapter; 

 Visit MTI web site link: WWW.MTIXTL.COM for additional information about the 

instrument through Help and Support; 

 Contact us by tel: 510-525-3070 or email: info@mtixtl.com.

Maintenance and Caution 

1. In order to prevent the furnace module from splitting, the furnace shall be used after being 

heated for 1 hour at 120 oC and 2 hours at 300 oC if you firstly apply it or have left it aside for

long. Never keep the furnace temperature over rated temperature for avoiding damage on 

heating element or cover. Do not pour any liquid or melting metal into the module to keep clean 

inside. 

2. When applying the furnace with quartz tube and the temperature over 1000 oC, the high 

temperature part of the tube will be opaque (devitrification), it is a normal phenomenon because 

of quartz property. 

3. Set a medium heating rate and small temperature difference between adjacent segment when the 

furnace is cool. Please make a considerate setting on the heating rate in terms of the character of 

material sintered. 

4. Termly check the wire connection and link junction of the heating element. 

5. Change the silicon rubber ring inside the flange and reassemble the flange, or the vacuum 

system if the vacuum value declines obviously. 

6. Please refer to parameter “M5, P and t” setting if the temperature offset can not be eliminated 

and the difference between PV and SV goes far at 300 oC.

7. Working environment 

a. Circumstance temperature: -10~75 oC. 

b. Relative humidity: 85% 

c. Keep from electric dust, explosive and corrosive gas. 

d. Keep stable position when working. 

8. MTI’ furnace (not including tube and heating element) has one year warranty since it is shipped 

out. We will give you free maintenance if there is a quality problem. For any misuse and damage, 

we will make a charge according to the damage condition if there is a requirement of mending. 

Notice: MTI never suggest you put any noxious, explosive or flammable gas into the tube. Please 

remember that the inside air pressure ≤ 0.05 Mpa and over pressure use is forbidden when 

applying quartz tube or corundum tube at high temperature. We have no responsibility for your 

safety if you are out of this notice.

Quick Troubleshooting 

The furnace is unable to start up 

If the furnace can not turn on when you press the power button: 

 Be sure the furnace is plugged into and AC outlet with adequate power; 

 Fuse in controlling circuit might failure. Check the control circuit and replace the fuse. 

The temperature inside the chamber can’t go up 

 Temperature may be set too low, adjust the setting value of temperature; 
 Thermocouple may be failure, check and replace the thermocouple; 

 Temperature controller may be broken, check and replace the thermocouple; 

Real temperature inside the chamber does not match the setting value 

 Temperature sensor may be broken, replace the temperature sensor/thermocouple; 

Overheated protection alarm 

 Cool furnace down, and find reason why temperature is so high (program setting may be 

wrong); 

SV show “OraL” alternately 

 Thermocouple has open circuit, inspect thermocouple; 

SV show “HIAL” alternately 

 Furnace temperature/tube pressure is over upper limit, Please let the furnace naturally 

cooling down and then check out the reason of over-heating.