Thermo Electron 6540 Operating instructions

Analyze • Detect • Measure • Control™
Model 6540 and 6550 Series
Thelco Oven
Operating and Maintenance Manual
3177885 Rev. I Dated 05MAY06

Thermo Electron CorporationThermo Electron Corporation
MANUAL NUMBER 3177885
I 23443 5/06 Consolidated 230V manual (P/N 3179180) with 120V, no CE ccs
H -- 2/06 Knob part number from 3174902 to 3174903, page 14
G -- 1/06 Part number from 3176708 to 3176738, page 13
F -- 11/05 Part number from 3174892 to 3174903, page 14
E -- 7/05 new manual number (36100120 [34001783]), manufacture location
D -- 8/03 Add temperature control range specification, page 3-4
C -- 11/01 Add “plastics can melt”, page 8
B -- 8/99 Updated for new kit #s, pages 12-14
A -- 6/99 Initial release
REV ECR/ECN DATE DESCRIPTION By
Preface
3177885 Thelco Oven i
Current Model # Previous Model # Voltage
6540 70 120V
6541 70 230V
6545 70D 120V
6546 70D 230V
6550 70M 120V
6551 70M 230V
6555 70DM 120V
6556 70DM 230V
6542 130 120V
6543 130 230V
6547 130D 120V
6548 130D 230V
6552 130M 120V
6553 130M 230V
6557 130DM 120V
6558 130DM 230V
6544 160 230V
6549 160D 230V
6554 160M 230V
6559 160DM 230V
Table 1. Models Covered In This Manual

Thermo Electron Corporationii 3177885 Thelco Oven Thermo Electron Corporation
Preface
Important Read this instruction manual. Failure to read, understand and follow the instructions in this manual
may result in damage to the unit, injury to operating personnel, and poor equipment performance. V
Caution All internal adjustments and maintenance must be performed by qualified service personnel. V
Note The 230V models in this manual were designed specifically for the European market and are supplied with
a European-style power cord. For domestic use, a U.S.-style cord (P/N 3179481) must be ordered separately.
Models 6544, 6549, 6554, 6559 are only available in 230V and are supplied from the factory with both cord
styles. V
Material in this manual is for information purposes only. The contents and the product it describes are subject to
change without notice. Thermo Electron Corporation makes no representations or warranties with respect to this
manual. In no event shall Thermo be held liable for any damages, direct or incidental, arising out of or related to
the use of this manual.
©2003 Thermo Electron Corporation. All rights reserved.

Thermo Electron Corporation 3177885 Thelco Oven iiiThermo Electron Corporation
Preface
Important operating and/or maintenance instructions. Read the accompanying text carefully.
Potential electrical hazards. Only qualified persons should perform procedures associated with this
symbol.
Equipment being maintained or serviced must be turned off and locked off to prevent possible injury.
Hot surface(s) present which may cause burns to unprotected skin, or to materials which may be
damaged by elevated temperatures.
Marking of electrical and electronic equipment, which applies to electrical and electronic equipment
falling under the Directive 2002/96/EC (WEEE) and the equipment that has been put on the market
after 13 August 2005.
This product is required to comply with the European Union’s Waste Electrical & Electronic
Equipment (WEEE) Directive 2002/96/EC. It is marked with the WEEE symbol. Thermo Electron
has contracted with one or more recycling/disposal companies in each EU Member State European
Country, and this product should be disposed of or recycled through them. Further information on
Thermo Electron’s compliance with this directive, the recyclers in your country and information on
Thermo Electron products will be available at www.thermo.com.
Always use the proper protective equipment (clothing, gloves, goggles, etc.)
Always dissipate extreme cold or heat and wear protective clothing.
Always follow good hygiene practices.
Each individual is responsible for his or her own safety.

Thermo Electron Corporationiv 3177885 Thelco Oven Thermo Electron Corporation
Preface

3177885 Thelco Oven vThermo Electron Corporation
Table of Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
Unpacking and Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1
Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1
Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1
Explanation of Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-1
Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3
Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-4
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-5
Periodic Safety Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-6
Section 1
Section 2
Section 3
Section 4
Section 5
Section 6
Section 7

vi 3177885 Thelco Oven Thermo Electron Corporation
Maintenance and Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-1
Temperature Variance or Fluctuation . . . . . . . . . . . . . . . . . . . . . . . . .8-1
Temperature Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-2
Calibration (Digital Models Only) . . . . . . . . . . . . . . . . . . . . . . . . . . .8-2
Heat Loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-3
Heater Resistance Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-3
Parts Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-1
Heater Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-1
Heater Wire Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-1
Probe Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-2
Motor Replacement (Mechanical Models) . . . . . . . . . . . . . . . . . . . . .9-2
Control Replacement (Analog Models) . . . . . . . . . . . . . . . . . . . . . . .9-2
Control Replacement (Digital Models) . . . . . . . . . . . . . . . . . . . . . . .9-3
Door and Latch Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-3
Door Latch Grabber (on body of oven) . . . . . . . . . . . . . . . . . . . . . . .9-4
Electrical Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-1
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-1
Table of Contents
Section 8
Section 9
Section 10
Section 11

3177885 Thelco Oven 1-1Thermo Electron Corporation
Section 1 Introduction
Your satisfaction and safety are important to Thermo and a complete
understanding of this unit is necessary to attain these objectives.
As the ultimate user of this apparatus, you have the responsibility to
understand the proper function and operational characteristics of your
oven. This instruction manual should be thoroughly read and all operators
given adequate training before attempting to place this unit in service.
Awareness of the stated cautions and warnings, and compliance with
recommended operating parameters — together with maintenance
requirements — are important for safe and satisfactory operation. The unit
should be used for its intended application; alterations or modifications
will void the warranty.
Warning As a routine laboratory precaution, always wear safety glasses
when working with this apparatus. V
Warning This product is not intended, nor can it be used, as a sterile or
patient connected device. In addition, this apparatus is not designed for
use in Class I, II, or III locations as defined by the National Electrical
Code. V
Warning When unpacking this unit, use a mechanical lifting device or
enough people to easily lift the unit and place it in it’s proper location. V
Caution The benchtop, or other mounting surface, must be rigidly
constructed and capable of comfortably supporting the unit weight.
Do not mount this equipment on a flammable surface. V

3177885 Thelco Oven 2-1Thermo Electron Corporation
Section 2 Unpacking and Damage
Save all packing material if apparatus is received damaged. This product
was carefully packed and thoroughly inspected before leaving our factory.
Responsibility for safe delivery was assumed by the carrier upon acceptance
of the shipment; therefore, claims for loss or damage sustained in transit
must be made upon the carrier by the recipient as follows:
1. Visible Loss or Damage: Note any external evidence of loss or damage
on the freight bill or express receipt, and have it signed by the carrier's
agent. Failure to adequately describe such external evidence of loss or
damage may result in the carrier's refusing to honor your damage
claim. The form required to file such claim will be supplied by the
carrier.
2. Concealed Loss or Damage: Concealed loss or damage means loss or
damage which does not become apparent until the merchandise has
been unpacked and inspected. Should either occur, make a written
request for inspection by carrier's agent within 15 days of the delivery
date; then file a claim with the carrier since the damage is the carrier's
responsibility.
If you follow the above instructions carefully, we will guarantee our full
support of your claim to be compensated for loss from concealed damage.
DO NOT — for any reason — return this unit without first obtaining
authorization. In any correspondence to Thermo, please supply the
nameplate data, including catalog number and serial number.

3177885 Thelco Oven 3-1Thermo Electron Corporation
Section 3 General Information
This instruction manual encompasses the following models and their
specific electrical characteristics.
• Models 6540/6541, 6545/6546, 6542/6543, 6547/6548, 6544, and
6549 employ gravity convection as a method of heat transfer. Gravity
convection is defined as the natural tendency for heated air to rise due
to it's change in density and mass.
Air is drawn into the chamber through openings in the bottom of the
oven then heated as it passes over the electric heating coils and up
through the diffuser panel located on the bottom of the inner chamber.
A limited amount of the heated air is exhausted out of the chamber
through the openings in the vent cap located on the top of the oven
and the remaining air recirculates within the chamber.
Gravity convection ovens are ideal where forced air circulation cannot
be tolerated and for situations demanding gentle curing or long term
sample storage under closely controlled conditions. Gravity convection
ovens are ideal for drying powders, soil samples, paper goods,
semiconductors and cosmetics.
• Models 6540/6541, 6542/6543, and 6544 use an analog solid state
temperature control with analog solid state safety thermostat.
• Models 6545/6546, 6547/6548 and 6549 use a microprocessor control
with digital set point, digital display and digital safety thermostat.
• Models 6550/6551, 6552/6553, 6554, 6555/6556, 6557/6558 and
6559 ovens use mechanical convection as a method of heat transfer.
Mechanical convection can be defined as a positive and planned
directional air flow or forced air circulation within the chamber. Air is
drawn into the chamber through a vent tube located in the bottom of
the oven and is heated as it passes over the electric heating coils. The
air is blown through the duct network and forced into the chambers
through calculated, carefully designed openings in the side diffuser
walls.
A limited amount of the heated air is exhausted out the top of the
chamber through the vent shutter cap and the remaining air
recirculates within the chamber.

3-2 3177885 Thelco Oven Thermo Electron Corporation
Section 3
General Information
Mechanical convection ovens provide the most efficient means of heat
transfer as well as the most reproducible test conditions for repeat
operations. Mechanical convection allows for rapid heat up time for
high density loads, shortened recovery periods after door openings and
improved uniformity for extremely heat sensitive materials.
• Models 6550/6551, 6552/6553 and 6554 provide mechanical
convection of heat controlled by an analog solid state control with
analog solid state safety thermostat.
• Models 6555/6556, 6557/6558 and 6559 provide mechanical
convection of heat controlled by a microprocessor with digital set
point, digital display and digital safety thermostat.
• Environmental Conditions -
This instrument is designed to operate safely under the following
conditions:
• Indoor Use Only
• Temperature: 5° to 40° C
• Maximum Relative Humidity: 80% for temperatures to 22°C
• Maximum Altitude 2000 meters
Maximum performance is assured across the following temperature
range:
• 15ºC to 45ºC

3177885 Thelco Oven 4-1Thermo Electron Corporation
Section 4
Specifications
Specifications Gravity Convection
Model
6540/6541
Model
6542/6543 Model 6544 Model 6545/6546
Model
6547/6548 Model 6549
Temperature Control Electronic Microprocessor
Temperature Display 0°C to 250° Thermometer 3 Digit LED
Temperature Control Range 65°C to 250°
Temperature @ 100° C ±4.0 ±3.5
Uniformity @ 200° C ±4.5 ±4.5
Sensitivity ±0.3° C ±0.1°C
Minutes to reach Max.
Temperature 250° 60
*Recovery Time @ 100° C 810 12
(minutes) @ 200° C 510 12
Max. Air Changes/Hr 30 23 15 30 23 15
Chamber Volume cu. ft. 2.5 4.5 5.5 2.5 4.5 5.5
liters 71.5 129 157.5 71.5 129 157.5
Net Weight lbs. 100 130 145 100 130 145
kg 45.3 59 65.8 45.3 59 65.8
Dimensions (D x W x H)
Chamber inches 15-3/4x18-1/2x15 15-3/4x18-1/2x27 15-3/4x18-1/2x33 15-3/4x18-1/2x15 15-3/4x18-1/2x27 15-3/4x18-1/2x33
mm 400x470x381 400x470x686 400x470x838 400x470x381 400x470x686 400x470x838
**Overall inches 21-1/4x24x28 21-1/4x24x40 21-1/4x24x46 21-1/4x24x28 21-1/4x24x40 21-1/4x24x46
mm 540x610x711 540x610x1016 540x610x1168 540x610x711 540x610x1016 540x610x1168
Electrical 50/60 Hz 115V 1200W 10.4A 1700W 14.8A N/A N/A 1200W 10.4A 1700W 14.8A N/A N/A
230V 1200W 5.2A 1700W 7.4A 2000W 8.7A 1200W 5.2A 1700W 7.4A 2000W 8.7A
Shipping Dimensions in. 25x26x31-1/4 25x26x43-1/4 25x26x49-1/4 25x26x31-1/4 25x26x43-1/4 25x26x49-1/4
Shipping Weight lbs. 125 155 170 125 155 170
Max Number of Shelves 612 15 612 15
***Shelves Supplied 2
Shelf Dimensions in. 15.5 x 18
mm 390 x 455
Catalog Number 115V 3166782 3166784 - - 3166787 3166789 - -
230V 3166783 3166785 3166786 3166788 3166790 3166791
“* Door Open for 30 seconds
** Overall height includes vent cap and adjustable feet
*** Spacing between shelves is 1-7/8” (48mm)

4-2 3177885 Thelco Oven Thermo Electron Corporation
Section 4
Specifications
Specifications Mechanical Convection
Model
6550/6551
Model
6552/6553 Model 6554 Model 6555/6556
Model
6557/6558 Model 6559
Temperature Control Electronic Microprocessor
Temperature Display 0°C to 250° Thermometer 3 Digit LED
Temperature Control Range 40°C to 250°
Temperature @ 100° C ±3.0 ±2.0
Uniformity @ 200° C ±3.5 ±3.0
Sensitivity ±0.3°C ±0.1°C
Minutes to reach Max.
Temperature 250° 70
*Recovery Time @ 100° C 5 7 10 12
(minutes) @ 200° C 5 7 10 12
Max. Air Changes/Hr 52 34 19 52 34 10
Chamber Volume cu. ft. 2.5 4.5 5.5 2.5 4.5 5.5
liters 71.5 129 157.5 71.5 129 157.5
Net Weight lbs. 110 140 155 110 140 155
kg 50 63.5 70.3 50 63.5 70.3
Dimensions (D x W x H)
Chamber inches 15-3/4x18-1/2x15 15-3/4x18-1/2x27 15-3/4x18-1/2x33 15-3/4x18-1/2x15 15-3/4x18-1/2x27 15-3/4x18-1/2x33
mm 400x470x381 400x470x686 400x470x838 400x470x381 400x470x686 400x470x838
**Overall inches 21-1/4x24x28 21-1/4x24x40 21-1/4x24x46 21-1/4x24x28 21-1/4x24x40 21-1/4x24x46
mm 540x610x711 540x610x1016 540x610x1168 540x610x711 540x610x1016 540x610x1168
Electrical 50/60 Hz 115V 1300W 11.3A 1800W 15.6A N/A N/A 1300W 11.3A 1800W 15.6A N/A N/A
230V 1300W 5.6A 1800W 7.8A 2100W 9.1A 1300W 5.6A 1800W 7.8A 2100W 9.1A
Shipping Dimensions in. 25x26x31-1/4 25x26x43-1/4 25x26x49-1/4 25x26x31-1/4 25x26x43-1/4 25x26x49-1/4
Shipping Weight lbs. 135 165 180 135 165 180
Max Number of Shelves 612 15 612 15
***Shelves Supplied 2
Shelf Dimensions in. 15.5 x 18
mm 390 x 455
Catalog Number 115V 3166792 3166794 - - 3166797 3166799 - -
230V 3166793 3166795 3166796 3166798 3166800 3166801
“* Door Open for 30 seconds
** Overall height includes vent cap and adjustable feet
*** Spacing between shelves is 1-7/8” (48mm)

3177885 Thelco Oven 5-1Thermo Electron Corporation
Section 5 Installation
Caution Installation should be completed by qualified instrument
personnel only. V
The most uniform operating conditions will be obtained by placing the
oven in an area remote from drafts, ventilating outlets, radiators, and other
rapidly changing ambient conditions. To assure proper ventilation allow a
minimum of 3 inches of clearance between the rear, top and sides of the
oven and adjacent walls. If two or more ovens are to be placed side by side,
then allow 6 inches between them. The four legs on the bottom of the
oven can be turned to raise or lower the corners of the oven so that it sits
level on the table.
Warning For personal safety, this apparatus must be properly grounded. V
Most units detailed in this manual are equipped with three-pronged
(grounded) plug power cords. These mate with standard three-prong
receptacles to minimize the possibility of electric shock. The user should
have the wall receptacle and circuit checked by a qualified electrician to
make sure the receptacle is properly grounded.
Where a standard two-prong wall receptacle is encountered, it is the
personal responsibility and obligation of the user to have it replaced with a
properly grounded three-prong wall receptacle.
Warning Do not, under any circumstances, cut or remove the third
(ground) prong from the power cord. Do not use a two-prong adapter. V
Determine the total amount of current being used by other apparatus
connected to the circuit that will be used for this apparatus. It is critical
that the added current demand (see nameplate) of this and other
equipment used on the same circuit does not exceed the rating of the fuse
or circuit breaker.
Location
Electrical
Connections

5-2 3177885 Thelco Oven Thermo Electron Corporation
Section 5
Installation
Caution Be sure that the power supply is of the same voltage as specified
on the nameplate. V
Caution Be sure the wall receptacle is readily identifiable and easily reached
to disconnect the unit from the power source. V
Model 6557 115-volt units (Cat. No. 3166789) are equipped with non-
standard plugs (one horizontal and one vertical blade) and will require
installation of a special matching receptacle. To be in compliance with the
National Electrical Code, non-standard plugs and receptacles are required
to accommodate higher current draw.
The aforementioned models are rated at 15.6 amps.

Section 6 Explanation of Controls
Models 6540/6541, 6550/6551, 6542/6543,
6552/6553, 6544, and 6554
On/Off Switch - The on/off switch controls the flow of all electric power
to the oven. The blower motor in the mechanically convected models
will only be in operation with the power switch ON, and the timer not
at setting "0".
Temperature Control Knobs - Two control knobs, Temperature Control
and High Temperature Limit set the operating temperature and safety
set points respectively. The numerical graduations do not refer to any
specific temperature, but are simply for reference.
Temperature Control Pilot Lamps - These lamps indicate the status of the
controls. When the lamp above the Temperature Control is illuminated,
this indicates electric current is being applied to the heater. It is normal
for this lamp to cycle on and off during the operation of the oven. The
lamp above the High Temperature Limit is illuminated only when first
set. If this lamp is ON, it indicates that oven is controlling on the High
Temperature Limit thermostat which has taken over control of from the
Temperature Control thermostat.
When the High Temperature Limit lamp comes on it is due to either a
Temperature Control thermostat failure or that the High Temperature
Limit thermostat is set too close in value to the temperature control. In
this case a slight turn clockwise for the High Temperature Knob should
increase the span between them.
Timer - The timer controls how long the oven will stay on if a predeter-
mined time between one to twelve hours is desired. With the Timer set
to the HOLD position the oven will run continuously. If the Timer
knob is first turned past two hours then set to some value the oven will
then turn off after that value has timed out.
Glass Thermometer - Used to indicate oven temperature and determine
proper thermostat settings.
Light Switch - Turns interior lamp on and off.
3177885 Thelco Oven 6-1Thermo Electron Corporation

Models 6545/6546, 6555/6556, 6547/6548,
6557/6558, 6549, and 6559
On/Off Switch - The on-off switch controls the flow of all electric power
to the oven. The blower motor in the mechanically convected models
will always be in operation with the power switch "ON".
Digital Displays - Three digital displays show actual temperature, set point
temperature and hours.
Arrows - The arrow buttons will allow you to increment (^) or decrement
(v) the displayed temperature or time set point values.
Temp - The Temp button will allow you to select a set point value for
desired temperature.
High Limit - The High Limit button will allow you to select a set point
value for the desired high temperature limit.
Set - The Set button will allow you to enter the value you have selected
with the arrow buttons when you are either in Temp or High Limit
mode.
Mute - The Mute button will silence the audible alarm if activated.
Timer - The Timer Button will put the oven into either Continuous or
Timed mode, as indicated by the Hours digital display. When in
Continuous mode, the display will show -- (dashes); the Continuous
lamp is illuminated, and the oven runs constantly. When in Timed
mode, the display will show a numeral.
Start/Stop Button - The Start/Stop button is used to start the Timed oper-
ation or to interrupt the Timed cycle. When the Timed lamp is illumi-
nated, the oven will remain at the set point temperature for the time dis-
played. When the lamp is not illuminated, the oven is not heating and
the length of running time can be selected in hour increments using the
arrow buttons.
Light On/Off - The Light ON/OFF switch operates the interior chamber
lamp.
6-2 3177885 Thelco Oven Thermo Electron Corporation
Section 6
Explanation of Controls

Section 7 Operation
Warning This equipment has reachable hot surfaces. The operator should
take any precaution to avoid contact with these parts. V
Fully open the exhaust vent shutter cap on the top of the oven and keep it
open at all times. However, if the running the oven at the maximum rated
temperature it may be necessary to turn the cap to a more closed position
to retain heat.
Insert shelf supports into the holes punched in the side walls of the inner
chamber. Insert the shelves into the shelf supports and try to keep an equal
distance between shelves whenever possible. Try to position the shelves so
they can be withdrawn more than halfway without falling. Never cover the
shelves with foil or reduce their open surface area by more than 75%, this
will greatly reduce convection and hence uniformity and control will
suffer.
3177885 Thelco Oven 7-1Thermo Electron Corporation