Fisher Scientific 550 Series User manual

Fisher Scientific
IsotempâMuffle 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

Service Division (Repairs): 1-800-395-5442
Technical Support: 1-800-926-0505
Customer Service: 1-800-766-7000
Prior to calling for service, have the following information readily available:
CatalogNumber:
Serial Number:
DateofPurchase:
The catalog number and serial number can be found on the data plate located on
the left interior wall of the unit.

Table of Contents Isotemp Muffle Furnace
Introduction................................................................................................................. 1
Installation.......................................................................................................................... 2
Selecting a Location........................................................................................................................ 2
Unpacking ....................................................................................................................................... 2
Preparing the Furnace ..................................................................................................................... 3
Furnace Layout..................................................................................................................4
Operation............................................................................................................................ 5
Power On Reset............................................................................................................................... 5
Entering a Set Temperature............................................................................................................. 5
Setting the Display Offset ............................................................................................................... 5
Example Offset ......................................................................................................................... 6
Open Thermocouple.......................................................................................................... 6
Over-Temperature Indicator ............................................................................................. 6
Service................................................................................................................................ 7
Replacing a Heater .......................................................................................................................... 7
Replacing the Thermocouple .......................................................................................................... 7
Trouble Shooting Table..................................................................................................... 8
Replacement Parts ............................................................................................................ 9
Accessories and Supplies .............................................................................................. 10
Performance Characteristics.......................................................................................... 11
Specifications ..................................................................................................................12
Wiring Diagram ................................................................................................................ 13

Page 1Isotemp Muffle Furnaces
Introduction
Fisher Isotempâ550 Series Muffle Furnaces are available in three sizes:
small (Model 14), medium (Model 58) and large (Model 126). All models
provide PID microprocessor 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 operation. The furnace is heated by electric resistance
elements embedded in easily removable side and base panels. 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-segment display. A
heater LED located to the left of the temperature display indicates when
the heater is being energized.
For operation with chamber atmospheres other than air (N2, C02, etc), ex-
ternal 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..
Isotempâfurnaces incorporate a variety of safety features. When the fur-
nace 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 flahing “HIGH” on the display. A ventilated base design
prevents damage to the bench or countertop.
A three button control provides simple operation. Arrow keys serve to
increase or decrease the furnace temperature set point. A front panel
Mode key allows the user to toggle the display between set point
temperature or actual furnace temperature.

Page 2Isotemp Muffle Furnaces
Installation
Selecting a
Location
Unpacking
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.
CAUTION: Do not install closer than 6 inches to a wall of
combustible material.
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.
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 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.
CAUTION: REMOVE PACKING
MATERIALS INSIDE CHAMBER BEFORE
OPERATING.
Item
Furnace Assembly
Model 14 Model 14A
120 V, 50/60 Hz 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

Page 3Isotemp Muffle Furnaces
Preparing the
Furnace
Special
Precautions
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 chamber. Orient hearth plate
such that smooth surface faces upward. See Fig. 1, Page 4.
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 furnace (see Fig 1, Page 4). Use three screws to secure
the port flange to the exhaust port. Attach tubing to port flange
using a hose clamp (provided). Finally, route free end of tube to
fumehood or other outside vent. If desired, exhaust tube may be cut to
length using a hacksaw.
IsotempâMuffle Furnace chambers contain alumina silicate
ceramic fibers. With continued use at temperatures above 1000 °C
(1832 °F), these materials 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.
Before operating the furnace, 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 components which may ignite such materials.

Page 4Isotemp Muffle Furnaces
2
1
34
56
Hearth Plate
Thermocouple
Exhaust Port
7
Furnace Layout
1. Heater Indicator LED
2. Mode Key 5. Temperature Display Window
3. Increase Key 6. ON/OFF Power Switch
4. Decrease Key 7. Door Switch
See the following pages for keypad/display descriptions.

Page 5Isotemp Muffle Furnaces
Operation
Safety
Considerations
Power On Reset
Entering a Set
Temperature
Setting the
Display Offset
When operating the muffle furnace, always observe the following safety
precautions:
•Wear insulated gloves.
•Use tongs.
•Never stand in front of an open furnace.
•Use the supplied hearth plate on the chamber bottom.
•Wear safety goggles.
When power is initially turned on to the furnace, the display will show
“InIt” followed by the current furnace temperature reading. The control
display window shows furnace temperature in °C.
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.
NOTE: If no keypad activity occurs within 3 seconds, the
display will return to the temperature display mode.
2. In order to change the temperature setpoint, press the UP arrow
key to increase or the DOWN arrow key to decrease. Once either
keypad 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.
Isotemp Muffle Furnaces permit the user to calibrate the temperature
display and control point to a reference standard set up to read the interior
furnace temperature at any given point. With a display offset entered, the
temperature shown on the display will be the actual furnace temperature
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.

Page 6Isotemp Muffle Furnaces
Example Offset
Open
Thermocouple
Over-
Temperature
Indicator
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.
NOTE: If no keypad activity occurs within 3 seconds, the
display will return to the temperature display mode.
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 offset 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:
A desired setpoint of 450°C is entered and the furnace is allowed 1 hour to
stabilize to the setpoint. A reference temperature is then measured inside
the chamber to be 455°C. In order to match the temperature display to the
reference thermometer, a display offset of 5 is entered. The temperature
display is then increased by 5°C and the display is in agreement 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.
In the event the thermocouple becomes detached or broken, the display
will indicate so by showing “otc” (open thermocouple). When this
condition is encountered, the heaters are held off. Repair or replace the
thermocouple connection as needed to clear the display.
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.
NOTE: This condition can also be created by decreasing the
setpoint 100°C lower than the current chamber temperature
Allow the unit to cool and the “HIGH” temperature alarm will turn off
when it falls to within 25°C of the setpoint. The controller will then
resume normal heater control.

Page 7Isotemp Muffle Furnaces
Service
Replacing a
Heater
Replacing the
Thermocouple
CAUTION: Only qualified personnel should conduct
service to the furnace.
Always disconnect power cord from power supply
before servicing instrument.
All Fisher Isotemp 550 Series Muffle Furances 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.
To replace a defective heater, proceed as follows:
1. Disconnect power cord from the electrical outlet.
2. Open chamber door and allow door to remain open throughout
heater replacement.
NOTE: Allow chamber to cool to ambient temperature before
attempting repair.
3. Remove the screws that secure the perforated metal back panel fo
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 wires.
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 aside for later use.
6. Carefully install the replacement heater by reversing the
procedure in step 5 above.
CAUTION: Heater panel material is fragile. Exercise care
when inserting replacement panels into the furnace chamber.
Likewise, bend or flex the heater leads gently when necessary.
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 furnace.
9. When the above steps are complete, return the power cord to the
electrical outlet.
To replace a defective thermocouple, perform the following steps:
1. Perform steps 1 through 3 in Replacing a Heater.
2. Gently remove the thermocouple from inside the chamber by
pulling it through 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 thermocouple connection on the
back of the control board.

Page 8Isotemp Muffle Furnaces
Trouble
Shooting Table
5. Using a small flat blade screwdriver, unscrew the terminals
holding the thermocouple wire to the board.
6. Remove the thermocouple from the unit.
7. Install the replacement thermocouple by reversing the above
procedure.
NOTE: Verify the red thermocouple wire is connected to the
negative (-) control board terminal and the orange is
connected to the positive (+) terminal.
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 @ 1-800-926-0505.
Symptom Probable Cause Action
Furnace won’t power
up.
Circuit breaker
tripped.
Power switch in OFF
position.
Check circuit breaker
supplying furnace.
Throw power switch
to ON position.
Furnace controls
between 25 and 100°C
above setpoint.
Faulty solid-state
relay (SSR 1).
Replace SSR 1
Heater LED on but
furnace won’t heat.
Setpoint too low.
Door switch circuit
not functioning.
Bad safety relay.
Bad solid-state relay
(SSR1).
Defective heater
element(s).
Adjust setpoint above
current chamber temp.
Close door. If
problem persists,
check door switch.
Replace safety relay
(K1).
Replace defective
SSR1.
Replace heater
element(s).
Setpoint is higher than
chamber temperature
and Heater LED
doesn’t come on
Defective controller. Replace temperature
controller.
Otc error Open thermocouple Check thermocouple
connection, replace if
faulty.
See inside cover for service numbers.

Page 9Isotemp Muffle Furnaces
Replacement
Parts
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

Page 10 Isotemp Muffle Furnaces
Accessories and
Supplies
Model 550-126 (four required) SPN83633
(floor heater) SPN83638
Item PartNumber
Ceramic Wool (1 inch wide strip) SPN40885
Ledge (Model 126 Only) SPN83985
A variety 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

Page 11 Isotemp Muffle Furnaces
Performance
Characteristics
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 Time1
Model 14 15 minutes
Model 58,& 126 25 minutes
Recovery Time210 minutes
Cool Down Time (Door opened)
(1125°C to 200C) 25 minutes
1Rise time is defined as the time required to achieve 63% of the maximum
operating temperature of 1125°C with a set temperature of 1125°C.
2Rise time is defined as the time required to achieve 63% of the maximum
operating temperature of 1125°C with a set temperature of 1125°C.

Page 12 Isotemp Muffle Furnaces
Specifications
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

Page 13 Isotemp Muffle Furnaces
Wiring Diagram

Part Number: 83854 Rev. JFisher Scientific Co.
Isotemp Muffle Furnace 2000 Park Lane
Published: 10-2003 Pittsburgh, PA 15275-112