Fisher Scientific Isotemp 550 Series User manual

Isotemp®Muffle Furnace
550 Series
Instruction Manual
Model 14
Catalog No. 10-550-14 & 14A
Model 58
Catalog No. 10-550-58
Model 126
Catalog No. 10-550-126
83854 • 04/11/06

Table of Contents
Safety Information ..............................................................................................................................................3
Alert Signals..................................................................................................................................................3
Introduction..........................................................................................................................................................4
Installation ..........................................................................................................................................................5
Selecting a Location ....................................................................................................................................5
Unpacking ....................................................................................................................................................5
Preparing the Furnace ..................................................................................................................................6
Furnace Layout ..................................................................................................................................................7
Operation ............................................................................................................................................................8
Power On Reset ..........................................................................................................................................8
Entering a Set Temperature..........................................................................................................................8
Setting the Display Offset ............................................................................................................................8
Example Offset ............................................................................................................................................9
Open Thermocouple ....................................................................................................................................9
Over-Temperature Indicator..........................................................................................................................9
Service ..............................................................................................................................................................10
Replacing a Heater ....................................................................................................................................10
Replacing the Thermocouple ......................................................................................................................11
Troubleshooting ................................................................................................................................................12
Replacement Parts............................................................................................................................................13
Accessories and Supplies ................................................................................................................................14
Performance Characteristics ............................................................................................................................15
Specifications ....................................................................................................................................................16
Wiring Diagram..................................................................................................................................................17
Warranty ............................................................................................................................................................20

3
Your Fisher Isotemp®Programmable Muffle Furnace has
been designed with function, reliability, and safety in
mind. It is your responsibility to install it in conformance
with local electrical codes. It is most important that the
user follow installation instructions exactly as written.
Failure to do so is likely to lead to improper operation,
erroneous calibrations and possible damage to the equip-
ment. Do not attempt operation without this information.
When operating the furnace, always observe the following
Safety Precautions:
• Wear insulating gloves.
• Use tongs.
• Use safety goggles.
• Never stand in front of an open furnace.
• Use the supplied hearth plate on the chamber
bottom
Safety Information
Warning
Warnings alert you to a possibility of
personal injury.
Caution
Cautions alert you to a possibility of
damage to the equipment.
Note
Notes alert you to pertinent facts and
conditions.
Hot Surface
Hot surfaces alert you to a possibility
of personal injury if you come in con-
tact with a surface during use or for a
period of time after use.
Alert Signals

4
Introduction
Fisher Isotemp 550 Series Muffle Furnaces are available
in three sizes: small (Model 14), medium (Model 58) and
large (Model 126). All models provide PID microproces-
sor temperature control at operating temperatures from
50 to 1125°C (90 to 2057°F).
Furnace chambers are molded from alumina silicate
ceramic fibers. Use of this material provides low thermal
mass for fast heat-up and cool-down, as well as an
unusually low exterior furnace temperature for safe opera-
tion. The furnace is heated by electric resistance ele-
ments embedded in easily removable side and base pan-
els. The heating elements are designed to ensure
extended service life, even in atmospheres characteristic
of high-sulfur coal and coke samples.
Temperature readout can be easily viewed on the 7-seg-
ment display. A heater LED located to the left of the tem-
perature display indicates when the heater is being ener-
gized.
For operation with chamber atmospheres other than air
(N2, C02, etc), external gas supplies connect easily
through a provided 3/8-inch port. An Injection Port Kit
(10-550P) connected to the exhaust port allows
convenient venting of the chamber.
Isotemp furnaces incorporate a variety of safety features.
When the furnace door is opened, power is automatically
cut to the chamber heating elements. The heater power is
also cut out when the chamber temperature exceeds the
set temperature by 100°C or more. The alarm condition
is indicated by a flashing “HIGH” on the display. A venti-
lated base design prevents damage to the bench or coun-
tertop.
Athree button control provides simple operation. Arrow
keys service to increase or decrease the furnace temper-
ature set point. A front panel Mode key allows the user to
toggle the display between set point temperature or actual
furnace temperature.

Selecting a Location
Choose a location for the furnace, which 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 60lbs for the Model 14, 90lbs for the Model 58 or
110lbs for the Model 126. Appropriate electrical power
must be available. Locate the furnace within three feet of
the power outlet so that no extension cord is required.
It is recommended that the site have facilities for venting
an accessory Exhaust Tube Assembly (Cat. No.10-490-
10) which is available for use with the furnace.
Alternatively, the furnace may be located in a fume hood if
samples are expected to produce toxic volatiles.
Unpacking
Fisher Isotemp Muffle Furnaces are shipped in a single
carton. After unpacking, locate each item shown in the list
below. Report any missing items, by name and part num-
ber, to your Fisher branch or representative. In the event
of shipping damage, retain the carton and packing materi-
al and file a claim with the final carrier.
Item
Furnace Assembly
Model 14 120 V, 50/60 Hz
Model 14A 208/240V, 50/60 Hz
Model 58 208/240 V, 50/60 Hz
Model 126 208/240 V, 50/60 Hz
Hearth Plate
Shelf (Model 126 Only)
Instruction Manual
Warranty Card
5
Installation
Caution
Do not install closer than 6 inches
to a wall of combustible material.
Caution
Remove packing materials inside
chamber before operating.

6
Preparing the Furnace
To prepare the muffle furnace for operation, perform the
following procedures:
1. Make certain all packing material is removed
from furnace chamber.
2. Place hearth plate on the bottom of the cham-
ber. Orient hearth plate such that smooth sur-
face faces upward. See Fig. 1.
3. With the Model 126, the supplied shelf may be
used. If desired, install shelf by sliding it onto
top of ledge protruding from each side of the
inner chamber walls.
4. If installing the accessory Exhaust Tube
Assembly, first locate exhaust port at top of fur-
nace (see Fig 1). Use three screws to secure
the port flange to the exhaust port. Attach tub-
ing to port flange using a hose clamp (provided).
Finally, route free end of tube to fume hood or
other outside vent. If desired, exhaust tube may
be cut to length using a hacksaw.
INSTALLATION
Warning
Isotemp Muffle Furnace chambers
contain alumina silicate ceramic fibers.
With continued use at temperatures
above 1000°C (1832 °F), these materi-
als slowly convert to crystalline silica
(cristobalite). Long-term exposure to
airborne cristobalite may result in
severe respiratory diseases in
humans. Tests with laboratory animals
suggest that cristobalite is a possible
carcinogen. Short-term effects may
include irritation to skin, eyes and the
respiratory tract. Please consult the
Material Safety Data Sheet (MSDS)
provided by Fisher Scientific for further
information.
Warning
This unit is not explosion proof. Do
not use in the presence of flammable
or combustible materials; fire or explo-
sion may result. Unit contains compo-
nents that may ignite such materials.

Figure 1 – Furnace Layout
7
INSTALLATION
2
1
4
56
Hearth Plate
Thermocouple
Exhaust Port
7
1 Heater Indicator LED 5 Temperature Display Window
2 Mode Key 6 ON/OFF Power Switch
3 Increase Key 7 Door Switch
4 Decrease Key
See the following pages for keypad/display descriptions.

8
Operation
Power on Reset
When power is initially turned on to the furnace, the dis-
play will show “InIt” followed by the current furnace tem-
perature reading. The control display window shows furn-
cace temperature in °C.
Entering a Set Temperature
To enter a temperature setpoint, perform the following
steps:
1. With the power switch in the ON position, press
the Mode keypad. The display shows the latest
temperature setpoint.
2. In order to change the temperature setpoint,
press the UP arrow key to increase or the
DOWN arrow key to decrease. Once either key-
pad is pressed the decimal point will illuminate
to indicate a change in setpoint. Hold the
UP/DOWN keypad in until the desired setpoint
is reached.
3. Press the MODE keypad again or don’t press
any keypad for 3 seconds and the setpoint will
update with the setpoint indicated on the display.
Once the desired setpoint is entered, the heater indicator
LED will light and the chamber will begin to heat towards
the setpoint.
Setting the Display Offset
Isotemp Muffle Furnaces permit the user to calibrate the
temperature display and control point to a reference stan-
dard set up to read the interior furnace temperature at
any given point. With a display offset entered, the temper-
ature shown on the display will be actual furnace temper-
ature plus or minus the display offset selected.
To enter a display offset, carry out the following steps:
1. Place power switch in the OFF position.
Note
If no keypad activity occurs within 3
seconds, the display will return to the
temperature display mode.

2. While pressing the MODE keypad, place the power
switch in the ON position. The display now shows
the current offset value. The display offset values
are limited to a range of ±30°C.
3. Press and hold the UP arrow keypad to increase or
the Down arrow keypad to decrease the offset
value.
4. Press the MODE keypad again to enter the new off-
set value or wait 3 seconds and the new value will
automatically be entered.
When finished, the temperature display will be updated based
on the offset value entered. For example:
Example Offset
Adesired setpoint of 450°C. is entered and the furnace is
allowed 1 hour to stabilize to the setpoint. A reference temper-
ature is then measured inside the chamber to be 455°C. In
order to match the temperature display to the reference ther-
mometer, a display offset of 5 is entered. The temperature
display is then increased by 5°C and the display is in agree-
ment with the reference standard. The control will then cut the
heater ON time down so that the chamber cools by 5°C, thus
matching the desired setpoint.
Open Thermocouple
In the event the thermocouple becomes detached or broken,
the display will indicate so by showing “otc” (open thermocou-
ple). When this condition is encountered, the heaters are held
off. Repair or replace the thermocouple connection as needed
to clear the display.
Over Temperature Indicator
If the temperature in the chamber exceeds the setpoint by
100 C, the display will warn the user by flashing “HIGH” along
with the current chamber temperature. Also, the safety relay
will cut the heater circuit out and de-energize the heater.
Allow the unit to cool and the “HIGH” temperature alarm will
turn off when it falls to within 25°C of the setpoint. The con-
troller will then resume normal heater control.
OPERATION
Note
If no keypad activity occurs within 3
seconds, the display will return to the
temperature display mode.
9
Note
This condition can also be created by
decreasing the setpoint 100 C lower
than the current chamber temperature.

10
Service
Caution
Only qualified personnel should con-
duct service to the furnace.
WARNING
Always disconnect power cord from
the power supply before servicing
instrument.
All Fisher Isotemp 550 Series Muffle Furnaces use wall
heaters. The Model 550-58 and 550-126 also incorporates
a floor heater to maintain uniform heating. The following
sections describe procedures for replacing a heater or the
control thermocouple.
Replacing a Heater
To replace a defective heater, proceed as follows:
1. Disconnect power cord from the electrical out
let.
2. Open chamber door and allow door to remain
open throughout heater replacement.
3. Remove the screws that secure the perforated
metal back panel of the furnace main chassis.
Remove the panel and set it aside.
4. Loosen two heater terminal screws located on
the terminal barrier strip. Straighten the lead
screws.
5. Carefully withdraw the defective heater from the
chamber. Ceramic wool insulated surrounding
heater wires will fall into the furnace chamber.
Remove it and set it aside for later use.
6. Carefully install the replacement heater be
reserving the procedure in step 5 above.
7. Carefully re-attach the heater terminals by
reversing step 4. Then refill the holes around
heater leads with ceramic wool preserved from
step 5.
8. Re-install perforated metal back panel of the fur-
nace.
9. When the above steps are complete, return the
power cord to the electrical outlet.
Note
Allow chamber to cool to ambient tem-
perature before attempting repair.
Caution
Heater panel material is fragile.
Exercise care when inserting replace-
ment panels into the furnace chamber.
Likewise, bend or flex the heater leads
gently when necessary.

11
SERVICE
Replacing the Thermocouple
To replace a defective thermocouple, perform the follow-
ing steps:
1. Perform steps 1 through 3 in Replacing a
Heater.
2. Gently remove the thermocouple from inside the
chamber by pulling it though the back wall of the
furnace.
3. Gently lie the furnace on its side so as to
expose the bottom perforated screen.
4. Remove the screen and locate the thermocou-
ple connection on the back of the control board.
5. Using a small flat blake screwdriver, unscrew
the terminals holding the thermocouple wire to
the board.
6. Remove the thermocouple from the unit.
7. Install the replacement thermocouple by revers-
ing the above procedure.
Note
Verify the red thermocouple wire is
connected to the negative (-) control
board terminal and the orange is con-
nected to the positive (+) terminal.

Symptom Probable Cause Action
Furnace won’t power up. Circuit breaker tripped. Check circuit breaker
supplying furnace.
Power switch in OFF Throw power switch
position. to ON position.
Furnace controls between Faulty solid-state relay Replace SSR 1
25 and 100°C above setpoint. (SSR 1).
Heater LED on but furnace Setpoint too low. Adjust setpoint above current
won’t heat. chamber temp.
Door switch circuit not Close door. If problem
functioning. persists, check door switch.
Bad safety relay. Replace safety relay (K1).
Bad solid-state relay Replace defective SSR1.
(SSR1).
Defective heater Replace heater element(s).
element(s).
Setpoint is higher than Defective controller. Replace temperature
chamber temperature and controller.
Heater LED doesn’t come on
Otc error Open thermocouple Check thermocouple
connection, replace if faulty.
12
Troubleshooting
This table is intended to assist in resolving user-correctable furnace problems by relating symptoms to
their likely causes. If service beyond the scope of this table is required, contact Fisher Technical Support
at 1-800-926-0505.

Replacements for muffle furnace parts serviceable by the user
may be ordered, by part number, from Fisher Scientific Co.
Item Part Number
Line Cord and Plug
Model 550-14, (120V) SPN103011
(208/240V) SPN95774
Model 550-58 (208/240V) SPN95774
Models 550-126 (208/240V) SPN83910
Temperature Controller
120V SPN103002
240V SPN103041
Cooling Fan
120VAC SPN83915
240VAC SPN83916
Thermocouple Assembly SPN103058
Solid State Relay (SSR) SPN83917
Safety Relay (SR) SPN102260
Rocker Switch (ON/OFF), Circuit Breaker
120V SPN95499
208V/240V SPN83914
Door Switch SPN83926
Shelf (Model 550-126 Only)
For Loads < 3 lbs (supplied) 10-750S
For Loads > 3 lbs (accessory) SPN83893
Hearth Plate
Model 550-14 SPN83890
Model 550-58 SPN83891
Model 550-126 SPN83891
Side Heaters
Model 550-14 (two required) SPN83636
Model 550-58 (two required) SPN83633
(floor heater) SPN83638
13
Replacement Parts

Item Part Number
Ceramic Wool (1 inch wide strip) SPN40885
Ledge (Model 126 Only) SPN83985
Avariety of accessories and supplies suitable for use with the Isotemp
Muffle Furnaces are available from Fisher. Catalog numbers of commonly
used items are listed below for convenience.
Item Catalog Number
Crucibles, Fused Quartz w/lid (set of 4) 10-490-4
Crucible, Porcelain, 10 ml 07-965C
Crucible, Porcelain, 15ml 07-965D
Exhaust Tube Assembly 10-490-10
Gloves 19-062-844
Grinding Mill 08-415
High Temperature Markers 13-382-16
Jumbo Crucible Tongs, Stainless 15-207
Crucible Rack Handle 10-490-17
Free Standing Shelf 10-651S
Crucible Racks (for Fused Quartz Crucibles)
Model 650-14, 750-14 10-490-6
Model 650-58, 750-58 10-497-5
Model 650-126, 750-126 10-497-5
Crucible Racks (for Porcelain Crucibles)
Model 650-14, 750-14 10-490-5
Model 650-58, 750-58 10-497-10
Model 650-126, 750-126 10-497-10
Injection Port Kit 10-550P
14
Accessories and Supplies

Operating Range 50°C to 1125°C (90°F to 2025°F)
Average Temperature Uniformity
Model 14 ±5°C (±9°F)
Model 58 ±8°C (±14.4°F)
Model 126 ±10°C (±18°F)
Average Temperature Stability ±1°C (±2°F)
Set Point Repeatability ±1°C (±2°F)
Set Point Accuracy
Model 14 ±5°C (±9°F)
Model 58 ±10°C (±18°F)
Model 125 ±15°C (±27°F)
Rise Time
Model 14 15 minutes
Model 58 & 126 25 minutes
Recovery Time 10 minutes
Cool Down Time (Door opened)
(1125°C to 200°C) 25 minutes
15
Performance Characteristics

Electrical Requirements
Model 14
Cat. No. 10-550-14 120VAC, 50/60 Hz
Cat. No. 10-550-14A 208/240VAC, 50/60 Hz
Model 58
Cat. No. 10-550-58 208/240VAC, 50/60 Hz
Model 126
Cat. No. 10-550-126 208/240VAC, 50/60 Hz
Power Requirements
Model 14 1200 Watts
Model 58 3000 Watts
Model 126 4600 Watts
Chamber Volumes
Model 14 0.14 cu ft
Model 58 0.58 cu ft
Model 126 1.26 cu ft
Chamber Dimensions
Model 14 6 x 10 x 4 inches
Model 58 12 x 14 x 6 inches
Model 126 12 x 14 x 13 inches
16
Specifications

17
Wiring Diagram

18

19

20
2555 Ker
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d
Dubu
q
ue, Iowa 5200
1
Phone: [phone]
Fax: [phone]
www.fishersci.com
Warranty
Laboratory instruments and equipment manufactured by Fisher Scientific Company L.L.C. – Laboratory
Equipment Division (hereinafter called “the Company”) are warranted only as stated below.
Subject to the exceptions and upon the conditions specified below, the Company agrees, at its election, to
correct by repair, by replacement, or by credit to the purchaser, any defect of materials or workmanship which
develops within one year (13 months for refrigerator and freezer products) from the date of purchase by the
original purchaser by the Company or by an authorized dealer of the Company provided that investigation or
factory inspection by the Company discloses that such defect developed under normal and proper use
The exceptions and conditions mentioned above are the following:
a. The Company makes no warranty concerning components or accessories not manufactured by it,
such as tubes, batteries, etc. However, in the event of the failure of any component or accessory not
manufactured by the Company, the Company will give reasonable assistance to the purchaser in
obtaining from the respective manufacturer whatever adjustment is reasonable in the light of the
manufacturer’s own warranty.
b. The Company shall be released from all obligations under its warranty in the event repairs or
modifications are made by persons other than its own service personnel or authorized dealer
personnel unless such repairs by others are made with the written consent of the Company.
c. THE COMPANY MAKES NO WARRANTY OF MERCHANTABILITY, FITNESS FOR ANY
PARTICULAR PURPOSE, OR ANY OTHER WARRANTY, EXPRESS OR IMPLIED, EITHER IN
FACT OF BY OPERATION OF LAW,…STATUTORY OR OTHERWISE.
d. The above warranty and the above obligations to repair, replace, or credit are complete and
exclusive and the Company expressly disclaims liability for lost profits or for special, indirect,
incidental, consequential, or exemplary damages of any nature whether attributable to contract,
warranty, negligence, strict liability, or otherwise even if the Company has been advised of the
possibility of such damages.
e. Representations and warranties made by any person, including dealers and representatives of the
Company, which are inconsistent or in conflict with the foregoing warranty shall not be binding upon
the Company unless reduced to writing and signed by an officer of the Company.