Fisher Scientific Isotemp 800 Series User manual

Isotemp®Programmable Ovens
800 Series
Model 825F (Small)
Catalog # 13-247-825F & -825FC - Domestic
Catalog # 13-247-826F & -826FC - International
Model 838F (Medium)
Catalog # 13-247-838F & -838FC - Domestic
Catalog # 13-247-839F & -839FC - International
Model 851F (Large)
Catalog # 13-247-851F & -851FC - Domestic
Catalog # 13-247-852F & -852FC - International
104502 • 3/28/06 Serial Number________________________

Introduction ........................................................................................................................................................ 3
Specifications ......................................................................................................................................................4
Performance Characteristics ........................................................................................................................4
Electrical Requirements................................................................................................................................4
Power Requirements ....................................................................................................................................4
Chamber Volumes ........................................................................................................................................4
Chamber Dimensions ..................................................................................................................................4
Installation ..........................................................................................................................................................5
Selecting a Location ....................................................................................................................................5
Unpacking ....................................................................................................................................................5
Preparing the Oven ......................................................................................................................................6
Power Switch ................................................................................................................................................6
Controls ..............................................................................................................................................................7
Display ..........................................................................................................................................................7
Keypad..........................................................................................................................................................8
Operation ............................................................................................................................................................9
Safety Precautions........................................................................................................................................9
Control Mode ................................................................................................................................................9
Ramp and Soak Mode................................................................................................................................10
Program Steps............................................................................................................................................10
Creating a Ramp and Soak Program..........................................................................................................11
Running, Stopping or Resuming a Program ..............................................................................................14
An Example Program..................................................................................................................................17
Menu Items ................................................................................................................................................19
Units (°C/°F)................................................................................................................................................20
Power Loss Options....................................................................................................................................21
Serial Communications ..............................................................................................................................22
High Alarm ..................................................................................................................................................23
Open Sensor ..............................................................................................................................................23
Service ..............................................................................................................................................................24
Replacing the Door Gasket ........................................................................................................................24
Accessing the Electronics ..........................................................................................................................25
Replacing the Heater ..................................................................................................................................26
Replacing the Cooling Fan ........................................................................................................................26
Replacing the Circulating Fan Motor ..........................................................................................................27
Replacing the Controller ............................................................................................................................28
Replacing the Solid State Relay ................................................................................................................28
Replacing the Safety Relay ........................................................................................................................29
Replacing the Thermocouple......................................................................................................................29
Replacing the Door Hinges ........................................................................................................................30
Replacing the Door Handle ........................................................................................................................30
Adjusting the Door Cam ............................................................................................................................30
Troubleshooting ................................................................................................................................................32
Replacement Parts............................................................................................................................................33
Schematic..........................................................................................................................................................34
Warranty ............................................................................................................................................................36
2
Table of Contents

Fisher Isotemp 800 Series forced air, programmable
ovens are available in three sizes: small (Model 825),
medium (Model 838) and large (Model 851). All models
provide PID microprocessor control at operating tempera-
tures ranging from 50°C (122°F) to 325°C (617°F).
The system microprocessor permits the user to customize
one to four programs, each containing up to 24 steps.
The user can program ramps, soaks or jumps between
steps. The programs are stored in non-volatile memory
to preserve their contents.
Temperature readouts and control parameters are shown
on 7-segment, red, light-emitting diode (LED) displays.
Two additional LEDs indicate when heater power is being
applied or an over temperature condition is encountered.
The Model 825 accommodates a maximum of five
shelves. The Models 838 and 851 hold eight and eleven
shelves, respectively.
Isotemp ovens incorporate a variety of safety features. A
safety backup is built into the controller software. If the
primary heater control fails, the backup will maintain con-
trol at 5°C above the set point. A circuit breaker protects
the oven from power surges.
3
Introduction

4
Power Requirements
Models 825 1800 W
Models 838 3300 W
Models 851 3300 W
Chamber Volumes
Models 825 2.5 cu ft
Models 838 3.8 cu ft
Models 851 5.0 cu ft
Chamber Dimensions
(W x D x H)
Models 825 18 x 18 x 13.5 in
Models 838 18 x 18 x 20 in
Models 851 18 x 18 x 26.5 in
Performance Characteristics
Operating Range 50 to 325°
Average Uniformity @ 200°* ±2°C
Resolution 1°C
Control Sensitivity ±0.25°C
Recovery Time @ 200°C
Model 825 1.5 minutes
Model 838 1.5 minutes
Model 851 3.5 minutes
Average Rise Time to 325°C
Model 825 60 minutes
Model 838 40 minutes
Model 851 40 minutes
Air Exchanges
Model 825 61/hr
Model 838 41/hr
Model 851 31/hr
BTU/hr Output @100°C @200°C
Model 825 1085 2650
Model 838 1355 3380
Model 851 1690 3950
*as per ASTM E-145
Electrical Requirements
Model 825
Cat. No. 13-247-825F/FC 120 V, 50/60 Hz
Cat. No. 13-247-826F/FC 240 V, 50/60 Hz
Model 838
Cat. No. 13-247-838F/FC 240 V, 50/60 Hz
Cat. No. 13-247-839F/FC 240 V, 50/60 Hz
Model 851
Cat. No. 13-247-851F/FC 240 V, 50/60 Hz
Cat. No. 13-247-852F/FC 240 V, 50/60 Hz
Specifications

5
Selecting a Location
Choose a location for the oven that will provide an area of
approximately four square feet (2 ft x 2 ft). The bench or
table selected must be capable of supporting at least 115
lbs for the Model 825, 120 lbs for the Model 838, or 130
lbs for the Model 851. A minimum 2 inch air space is
needed around the unit. Appropriate electrical power must
be available. Locate the oven within three feet of the
power outlet so that no extension cord is required.
Unpacking
Fisher Isotemp®Ovens are shipped in a single carton.
After unpacking, locate each item shown in the list below.
Report any missing items, by name and part number, to
your Fisher branch or representative. In the event of
shipping damage, retain the carton and packing material
and file a claim with the final carrier.
Item
Oven Assembly
Models 825 (small)
120 V (domestic)
240 V (international)
Models 838 (medium)
240 V (domestic)
240 V (international)
Models 851 (large)
240 V (domestic)
240 V (international)
Shelves
Models 825 and 838 (one provided)
Models 851 (two provided)
Shelf Supports
Models 825 and 838 (two provided)
Models 851 (four provided)
Instruction Manual
Warranty Card
Installation

6
Preparing the Oven
To prepare the oven for operation, perform the following
procedures:
1. Install the shelf(ves).
2. Make certain all packing material has been
removed from oven chamber.
3. Connect the line cord to an appropriate electri-
cal outlet.
4. The oven is now ready for operation. No prelimi-
nary adjustments or calibrations are required.
Depending on the customer application and cus-
tomer laboratory procedures an initial calibration
may be done at this point.
Power Switch
The 800 Series ovens feature a front panel mounted
power switch which is a Switch combination power switch
and circuit breaker, eliminating the need for separate
fusing. The circuit breaker will interrupt power in the event
of an oven heater malfunction. Press the I (upper) half of
the rocker-type power switch to the in position to turn the
oven on. Press the 0 (lower) half to the in position to turn
off oven power. To reset the breaker, first place the switch
to the off position, then return it to the on position.
INSTALLATION
Caution
See data plate on oven for voltage,
current and line frequency specifica-
tions. Check that the power require-
ments of the oven will not overload the
circuit to which it will be connected.

Display
The Fisher 800 Series Programmable Ovens are
equipped with a digital PID control routine that gives pre-
cise temperature controlability. The control is capable of
storing multiple 24-step programs for ramp and soak pro-
filing.
The following sections briefly describe the locations and
functions of various display fields and keypad controls.
More detailed descriptions are provided, when required,
in the operating sections of the manual.
The 800 Series controller features two bright, one-half
inch, 7-segment LED displays used in setting up the oven
program or reading oven temperature. Two smaller LEDs
indicate, respectively, an alarm condition or when power
is being applied to the oven heaters. Each display field is
discussed separately below.
Controls
Heat
Indicator
Program Run Indicator
Set Display
Alarm
Indicator
Actual
Display
Figure 1: Display Fields
Set Display In the Control and Ramp and Soak modes, shows the oven set temper-
ature. During setup and programming, indicates control parameters to be set.
Actual Display In the Control and Ramp and Soak modes, shows the actual oven
temperature. During setup and programming, indicates the numerical value assigned
to the currently displayed control parameter.
Heat Indicator Lights when power is being supplied to the oven heater.
Alarm Indicator Lights if the actual oven temperature exceeds the alarm tempera-
ture. The alarm temperature is factory-adjusted to be 5°C above the set temperature.
Run Indicator Indicates a ramp and soak program is running. This indicator is off
during control or program editing modes. 7

8
Keypad
The 800 Series incorporates a four-key, tactile keypad
(see Figure 1). The function of each key is discussed
individually below.
During programming or setup, successively pressing the
Menu Key causes the controller display to sequentially
step through menu selections.
In Control mode, pressing the Up Arrow Key increases
the oven set temperature, as indicated on the Set Display.
During programming or setup, used to step through menu
options.
In Control mode, pressing the Down Arrow Key decreases
the oven set temperature, as indicated on the Set Display.
During programming or setup, used to step through menu
options.
Alternates oven operation between the Control and
Program Run modes. See Running Stopping or
Resuming a Program for instructions on using this fea-
ture.
CONTROLS

Safety Precautions
Before operating ovens, always observe the following safety
precautions:
• This unit is not explosion proof. Do not use in the
presence of flammable or combustible materials;
Fire or explosion may result. Unit contains compo-
nents that may ignite such materials.
• Fumes and spillage from acidic solutions cause cor-
rosion of the stainless steel chamber. Care should
be taken to maintain a neutral pH at all times.
• The heater for the unit is in the bottom of the unit.
Surface temperatures at the bottom cover of the unit
may be higher than set point temperature. For
example: A plastic container on the heater cover
may become hot enough to melt/burn the container
at settings below the melting point of plastic. Do not
place items on the heater cover.
• Wear insulated gloves.
• Use tongs.
• Never stand in front of an open oven.
• Use safety goggles.
The 800 Series ovens feature two operating modes:
• Control
• Ramp and Soak
Each is discussed separately in the following sections.
Control Mode
In Control mode operation, the oven maintains a set tempera-
ture until that set temperature is changed. The Actual and
Set Displays will indicate current chamber temperature and
the temperature set point, respectively. To set a temperature
and initiate Control mode operation, perform the following:
1. Place the power switch in the ON position.
2. If the Run indicator is lit or blinking, press the Run
Key Pad until the indicator remains off.
Operation
9

10
3. Observe the set temperature in the Set Display
window.
4. To decrease the set temperature, press the
Down Arrow Key.
5. To increase the set temperature, press the Up
Arrow Key.
Ramp and Soak Mode
In Ramp and Soak mode of operation, the oven executes
a sequence of ramps and soaks programmed by the
operator. The controller is capable of providing up to 4
separate ramp/soak programs, each containing up to 24
steps. During a ramp period, the oven temperature is
controlled to increase at a linear rate set by the operator.
During a soak period, the oven maintains a constant tem-
perature for a time interval selected by the operator.
Program Steps
Aprogram consists of a sequence of operations or “steps”
which the oven controller may be set up to perform.
There are 24 program “steps” in each of the 4 available
programs. The programmed operations are executed in
the order entered: step 1, step 2, step 3, etc. A program
may have a maximum of 24 steps, or as few as two (one
must be an End).
Each program may consist of any of the four basic opera-
tions described below, except in step #1, which cannot be
a jump command. The corresponding LED display for
each operation is shown at the left.
ASet Point program step causes the oven set tempera-
ture (shown in the Set Display) to be linearly increased or
decreased (“ramped”) at a selected rate. The StPt opera-
tion begins at the current oven temperature and finishes
at the programmed Set Point temperature.
Soak causes the final set temperature from the preceding
step to be held for a time interval of up to 23 hours, 59
minutes and 59 seconds. This duration may be extended
by adding further Soak steps or using a Jump Loop (see
below).
OPERATION
Note
To rapidly increase or decrease the
set temperature press and hold the
appropriate arrow key. To slowly
increment or decrement the set tem-
perature one degree at a time, press
and immediately release the arrow
key.

AJump Loop operation causes program execution to
jump to another designated program step. Each program
step, up to the Jump Loop, is then sequentially repeated.
Use of a Jump Loop allows a programmed temperature
cycle to be repeated up to 100 times. A Jump Loop can-
not be used as the first step in a program.
Program execution proceeds sequentially through each
program step until an End is encountered, or until all 24
program steps have been completed. An End may be set
up to cause the oven to maintain the final set temperature
indefinitely or simply to turn off heater power.
If no End is used, all 24 program steps will be completed,
then the oven will maintain the final programmed set tem-
perature.
Creating a Ramp and Soak
Program
Creating a program consists of constructing a sequence
of the four basic operations (Set Point, Soak, Jump Loop
and End) to produce a desired temperature cycle. For
each operation selected, several options also must be
specified. To enter a ramp and soak program, perform
the following procedures:
1. Verify the Run LED is off. If it is on, press the
Run Key. If it is blinking, press the Menu Key
then the Run Key twice.
2. Press the Menu Key. The “No Program” display
should appear as shown on the left. NOTE: If no
key is pressed for one minute, the display auto-
matically reverts to Control mode.
3. Press the Up Arrow Key once to present the
program entry menu selection. The Actual dis-
play will change from no Program to 1 Program,
indicating entry into program #1.
4. Press the Menu Key to initiate entry of the first
program step. The display will then indicate the
first step number for program editing.
11
OPERATION
Note
During programming, the MODE key
serves as an "enter" key to select a
value shown on the Actual Display
for a corresponding parameter
shown on the Set Display.

5. Press the Menu Key to edit step #1, or use the
Up or Down Arrow Key to change the step num-
ber to the desired step for editing before press-
ing the Menu Key.
6. The Set Display then indicates “StyP” to signify
that step type must be selected from a menu of
four operations being shown in Actual Display.
The four menu selections are Set Point, Soak,
End or Jump Loop as shown to the left. Use the
Up/Down Arrow Keys to change the Actual
Display to the desired step type. Press the
Menu Key to enter the desired step type. NOTE:
For step 1 in a program, the jump loop option is
not available.
7. If the desired program step is an End, press
the Menu Key to select it when End is in the
Actual Display. Otherwise, skip to step 10.
8. The display shows one of the two options for an
End step. To view the selections, press either
the Up or Down Arrow Key. The End command
signifies the final step in a program.
9. If the final temperature is to be held indefinitely
at the end of the ramp and soak program, press
the Menu Key when “HoLd” is displayed on the
Actual Display. If heater power is to be turned
off at the end of the program, press the Menu
Key when Actual Display indicates “OFF”. Skip
to step 22.
10. If the desired program step is a ramp to a Set
Point, press the Menu Key to select it when the
Actual Display reads “SP.” Otherwise, skip to
step 13.
11. If a ramp to a Set Point is selected, the Set
Display first indicates “SP” to signify that the
operator must select a final target temperature,
or set point. Use the Up or Down Arrow Key to
adjust the Actual Display to indicate the desired
final temperature for the ramp. Press the Menu
Key to enter the selected set point temperature.
12
OPERATION

12. The Set Display then indicates “rAtE” to prompt
the operator to select a desired heating or cool-
ing rate in degrees/min. Press and hold or until
the desired rate is shown in the Actual Display.
Press the Menu Key to enter the selected rate.
Proceed to step 20.
13. If the desired program step is a Soak, press the
Menu Key to select it when the Actual Display
shows “SoAH.” Otherwise, skip to step 17.
14. If a Soak is selected, the Set Display first indi-
cates “HOUr” to signify that the operator must
select the number of hours that the current set
temperature will be maintained. Use the Up or
Down Arrow Key to adjust the Actual Display to
indicate the desired number of soak hours (max-
imum of 23). Press the Menu Key to enter the
selected number of soak hours.
15. The Set Display then shows “Min” to indicate
that the operator must select the number of
additional minutes for which the current set tem-
perature will be held. Use the Up or Down
Arrow Key to set the Actual Display to the
desired number of soak minutes (maximum of
59). Press the Menu Key to enter the selected
number of soak minutes.
16. The Set Display then shows “SEC” to indicate
that the operator must select the number of
additional seconds for which the current set
temperature will he held. Use the Up or Down
Arrow Key to adjust the Actual Display to indi-
cate the desired number of soak seconds (maxi-
mum of 59). Press the Menu Key to enter the
selected number of soak seconds. Proceed to
step 20.
17. If the desired program step is a Jump Loop,
press the Menu Key to select it when the Actual
Display shows “JL.”
18. If a Jump Loop is selected, the Set Display first
indicates “JS” to signify that the operator must
select the step number destination for the jump.
Use the Up or Down Arrow Key to adjust the
13
OPERATION

Actual Display to indicate the desired step num-
ber to jump to. Press the Menu Key to enter the
jump step. NOTE: The jump step number must
be lower than the current step number. The
jump cannot be to the current step or a higher
step.
19. The Set Display then shows “JC” to indicate that
the operator must select the number of times
the jump loop is to be repeated. Press the
Menu Key to enter the jump count.
20. The displays indicate “no rtn”. If further steps
are to be programmed, press the Menu Key to
continue at the “no return” prompt. This will
advance program editing to the next step num-
ber. Continue setting up the program at step 5
of this procedure.
21. If no further program steps are required, press
the Up or Down Arrow Key. The “yes return”
prompt will appear. Press the Menu Key to
return to Control mode operation.
22. When program editing is complete the controller
will then prompt to save the program, “1 Save”.
Press the Menu Key to save the program, or
use the Up or Down Arrow Key to change the
Actual Display to NO, which will leave the cur-
rent program as it was found.
To initiate the program, see Running a Program.
Running, Stopping or Resuming
a Program
Prior to running the program in memory, first make certain
that the current set temperature is the temperature from
which the program is to start. For example, a program
intended to ramp the oven temperature from ambient to
250°C, if started with the current set temperature at
300°C, will actually ramp the temperature down from
300°C to 250°C.
14
OPERATION

To run a program currently in memory, perform the follow-
ing steps:
1. Press the Run Key once. The Run indicator
light begins to flash and the displays indicate
which program in memory is ready to run. To
change program numbers, press the Up or
Down Arrow Key.
2. Press the Menu Key when the desired program
number is shown in the display. The display will
next prompt for the user to enter the program
step to begin the program run (usually step #1).
3. Use the Up or Down Arrow Key to change the
programs starting point. When the desired start-
ing step is displayed, press the Run Key to
begin. The program is running when the Run
LED is lit.
To stop a running program, press the Run Key. Oven
operation then returns to the Control mode, with the set
temperature at the last value achieved by the program.
To resume a stopped program, perform the following
steps:
1. Press the Run Key. The Run LED begins to
flash and the display indicates “1 Prog”.
2. Press the Menu Key twice. The resume pro-
gram command should appear on the displays.
The Actual Display will show the program num-
ber that was most recently run.
3. Press the Run Key again. The controller will
continue running the program at the point it was
terminated. The Run LED will again be lit.
While a ramp and soak program is running, the status of
the current program step may be viewed. With the Run
LED lit to indicate the program is running, successively
press the Menu Key. Each control parameter associated
with the current program step then is displayed sequen-
tially. The parameter type is indicated in the Set Display,
while the value for the parameter appears in the Actual
Display. A final press of the Menu Key returns the dis-
plays to tracking the actual and set temperatures.
15
OPERATION

The specific control parameters displayed in any instance
depend upon whether the current step is a Set Point or a
Soak operation. The sequence of control parameters dis-
played in each case, and the corresponding Set Display
messages, is as follows:
Ramp Step
End Set Point Target final temperature at the
completion of the ramp.
Rate Rate of change of temperature,
in °C or °F/min, for the ramp.
Jump Count If a Jump Loop is in progress,
indicates the number of times
the loop has been repeated.
Step Current program step.
Soak Step
Soak Point The soak temperature.
Hour Hours remaining in soak step.
Mins Minutes remaining in the soak
step.
Sec Seconds remaining in the soak
step.
Jump Count If a Jump Loop is in progress,
indicates the number of times
the loop has been repeated.
Step Current program step.
16
OPERATION

An Example Program
Implementing the following program provides a good
example of how to program the 800 Series ovens for
ramp/soak operations.
Step 1: Ramp from ambient to 200°C at
8.0°C/min.
Step 2: Ramp from 200°C to 325°C at 4 °C/min.
Step 3: Soak at 325°C for two hours
Step 4: Turn off power to the heaters and allow
to oven cool.
To set up and run this program, perform the following pro-
cedures.
Programming Step 1:
1. Verify the Run LED is not lit.
2. Press the Menu Key. The displays should show
(“no Prog”).
3. Press the Up Arrow Key to indicate which pro-
gram to edit. Press the Menu Key to edit pro-
gram #1 (“1 Prog”).
4. Press the Menu Key again to begin editing at
step #1 (“1 Step”).
5. Use the Up Arrow Key to display the ramp to a
Set Point operation. (“SP StyP”). Press the
Menu Key to select a Set Point operation as the
new program step 1.
6. Use the Up Arrow Key to adjust the Actual
Display to indicate the final temperature for the
first ramp, namely 200°C. Press the Menu Key
to enter the value.
7. The display will next prompt for the ramp rate.
Use the Up or Down Arrow Key to change the
Actual Display to 8.0 (8°/min). Press the Menu
Key to enter the ramp rate.
17
OPERATION

Programming Step 2:
8. Press the Menu Key again. The displays will
indicate the next program step for editing (“2
Step”). Press the Menu Key to enter the step.
9. Use the Up or Down Arrow Key to select the
step type for step #2. Press the Menu Key
when the displays indicate “SP StyP”. This will
enable the second ramp step.
10. Adjust the set point to 325°C using the Up Arrow
Key. When the displays indicate the new set
point, press the Menu Key to save it.
11. The display will next prompt for the ramp rate.
Use the Up or Down Arrow Key to change the
Actual Display to 4.0 (4°/min). Press the Menu
Key to enter the ramp rate.
Programming Step 3:
12. Press the Menu Key to continue programming.
Press the Menu Key again to initiate program-
ming the third step (“3 StEP”)
13. Use Up or Down Arrow Key to change the dis-
play to the Soak operation (“SoAh StyP”).
Press the Menu Key to select a constant tem-
perature soak period.
14. Use the Up or Down Arrow Key to adjust the
Actual Display to indicate the desired soak
hours, namely 2. (“2 HOUrS”). Press the Menu
Key to enter the soak hours.
15. Use the Up or Down Arrow Key to set the delay
minutes (“0 Min”). Press the Menu Key to enter
the minutes.
16. Use the Up or Down Arrow Key to set the
desired soak seconds (“0 SEC”). Press the
Menu Key to enter the seconds.
17. Press the Menu Key to continue programming.
(“no rtn”).
18
OPERATION

Programming Step 4:
18. Press the Menu Key to initiate programming the
fourth program step (“4 StEP”).
19. Use the Up or Down Arrow Key to adjust the
Actual Display to indicate the End operation
(“End StyP”). Press the Menu Key to select
End.
20. Use the Up or Down Arrow Key to select the
OFF command at the End of the program (“oFF
End”). Press the Menu Key to enter the com-
mand.
21. Press the Menu Key at the Save prompt to save
program 1 (“1 SAVE”) into memory.
To verify the program was entered correctly, repeat the
above steps (1-21) using the Menu Key to accept the val-
ues previously entered. Follow the procedure under
Running, Stopping or Resuming a Program to verify prop-
er operation.
Menu Items
The 800 Series Controller permits the operator to cus-
tomize some of the operating parameters available. The
following section describes those parameters and how to
set them to fit the needs of the operator.
The Temperature Offset is a value that is algebraically
added to the Actual Chamber Temperature, as measured
by the control thermocouple, in order to make the Actual
Chamber Temperature more accurate. In other words,
the temperature shown on the Actual Display will be the
actual oven temperature (measured at the control thermo-
couple) plus or minus the display offset selected.
Functionally, the offset feature permits the operator to
measure and calibrate such that the display will indicate
the temperature at a specific point or zone within the
oven.
19
OPERATION

To enter a Temperature Offset, carry out the following
steps:
1. With the oven in Control Mode, press the Menu
Key twice. This will bypass the program edit
mode and bring up the Temperature Offset (“0
CAL”) display.
2. To change the offset value, use the Up Arrow
Key (to increase) or Down Arrow Key (to
decrease).
3. Press the Menu Key when the appropriate value
is shown in the Actual Display.
4. Further menu items will begin to appear. Press
the Menu Key three additional times for the con-
troller to again display the Set and Actual tem-
peratures (control mode).
Once the Temperature Offset is changed, the actual dis-
play will reflect it. Allow the oven additional time to stabi-
lize. Compare the Actual Temperature display to the ref-
erence temperature. The displayed temperature is the
result of algebraically adding the actual temperature to
CAL value.
Thus, if a CAL value of 3 degrees is being used, a meas-
ured temperature of 50 degrees will be displayed as 53
degrees. Repeat steps 1 through 4 above if necessary.
Units (°C/°F)
The next menu item selects the desired temperature
units. The controller will display and program in units of
°C or °F. To determine the current units or to change the
current units follow the instructions below:
5. With the oven in Control Mode, press the Menu
Key three times. This will bypass the program
edit and temperature offset calibration mode and
bring up the Units (“C C_F”) display.
6. Use the Up or Down Arrow Key to change the
temperature units from °C to °F or vice versa.
Press the Menu Key when the desired units are
in the Actual Display.
20
OPERATION
Note
The ovens are factory calibrated
before shipping.