Thermo Scientific PR305225G User manual

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User Manual
Precision Compact Gravity Convection Ovens
Models PR305225G (658), PR305220G (652) and PR305220GCN (669)
Operating Manual and Parts List LTM1879X1 (7000652) Rev. 2

Thermo Scientific
MANUAL NUMBER LTM1879X1 (7000652)
2 31325 2/16/15 Added not-explosion-proof warning ccs
1 31259 10/27/14 Updated thermometer installation on pg 3-2 ccs
0 -- 4/30/10 Transfer to Marietta (was LTM1879X1 8/4/09) ccs
REV ECR/ECN DATE DESCRIPTION By
Preface
Compact Gravity Convection Ovens i
Models covered in this manual
Models Size Voltage
PR305225G (658) 1.7 cu ft 120V
PR305220G (652) 1.7 cu ft 240V
PR305220GCN (669) 1.7 cu ft 240V

Thermo Scientificii Compact Gravity Convection Ovens
Preface
Contains Parts and Assemblies
Susceptible to Damage by
Electrostatic Discharge (ESD)
CAUTION
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. s
Caution All internal adjustments and maintenance must be performed by qualified service personnel. s
Material in this manual is for information purposes only. The contents and the product it describes are subject
to change without notice. Thermo Fisher Scientific 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.
©2010 Thermo Scientific. All rights reserved.

Thermo Scientific Compact Gravity Convection Ovens iii
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 Fisher
Scientific 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’s compliance with this directive, the recyclers in your country and
information on Thermo Scientific products will be available at www.thermofisher.com.
4Always use the proper protective equipment (clothing, gloves, goggles, etc.)
4Always dissipate extreme cold or heat and wear protective clothing.
4Always follow good hygiene practices.
4Each individual is responsible for his or her own safety.

Thermo Scientificiv Compact Gravity Convection Ovens
Preface
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Compact Gravity Convection Ovens vThermo Scientific
Table of Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1
Unpacking and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1
Electrical Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1
Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1
Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1
Ordering Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1
Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-1
Section 1
Section 2
Section 3
Section 4
Section 5
Section 6
Section 7

Compact Gravity Convection Ovens 1-1Thermo Scientific
Section 1 Introduction
Thank you for selecting Thermo Scientific products for your equipment
needs.
The Thermo Scientific Precision Compact Gravity Convection Ovens are
designed for use in hospitals, industry, and school laboratories—wherever
there is a need for low-cost, yet reliable ovens for drying, sterilization,
baking, evaporation or similar type work. They are ideal for drying
glassware, drying and/or baking non-flammable crystalline chemicals, pre-
heating crucibles or other containers and drying filter paper strips or
rounds.
The temperature range, controlled by a bimetallic thermostat on the front
control panel, is from ambient +5°C to 210°C. A sheathed heater produces
the unit’s heat and a pre-set high limit bimetallic thermostat is standard on
all models. A pilot light on the control panel indicates oven operation
status.
Helping to retain chamber heat is one-inch thick insulation of semi-
refractory fibers that is sandwiched between the double walls of the
chamber. The interior walls of the chamber are aluminum and the shelves
are steel wire as is the surface covering the heater area—all for more
efficient distribution of heat.
These ovens are built for rugged performance and long life. Each has a
durable powder coated cold rolled steel exterior. To inhibit rust the shelves
are nickel-plated steel.
These instructions contain important operating and safety information.
The user must carefully read and understand these instructions before
using the oven. Your unit has been designed to optimize function,
reliability, safety and ease of use. It is the user’s responsibility to install the
oven in conformance with local electrical codes.

Compact Gravity Convection Ovens 2-1Thermo Scientific
Section 2 Specifications
Power Requirements
Model PR305225G: . . . .120 Volts, 50/60 Hz, 6.7 Amps, 800 Watts
Model PR305220G, PR305220GCN: . . . . .240 Volts, 50/60 Hz, 3.3
Amps, 800 Watts
Overall Dimensions
Models PR305225G, PR305220G, PR305220GCN: . . . .18½"W x
13½"D x 22½"H (47 x 34 x 57 cm)
Chamber Dimensions
Models PR305225G, PR305220G, PR305220GCN: . . . 16"W x 11½"
D x 16-1/8"H (41 x 29 x 41 cm)
Volume
Models PR305225G, PR305220G, PR305220GCN: . . . . 1.7 cu. ft.
(48.2 liters)
Shipping Weight
Models PR305225G, PR305220G, PR305220GCN: . . .57 lbs. (26 kg)
Performance Characteristics
Temperature Range . . . .. .All models ambient +5°C to 210°C
Uniformity at 100°C . . . . . . . . . . . . . . . . . . .±5.0°C
Control at 100°C . . . . . . . . . . . . . . . . . . . . . .±9.0°C
Environmental Operating Conditions
Pollution Degree*: . . . . . . . . . . . . . . . . . . . . . . . . .2
Installation Category*: . . . . . . . . . . . . . . . . . . . . . .II
Altitude: . . . . . .2000 Meters MSL (Mean Sea Level)
Humidity: . . . . . . .80% maximum, non-condensing
Electrical Supply: . . . . . . . . . . .120VAC or 240VAC
Voltage Tolerance: . . . . .±10% of normal rated line
Temperature: . . . . . . . . . . . . . . . . . . . .15°C to 40°C
Product Usage: This product is intended for use indoors only
*Refer to IEC 664-1

Compact Gravity Convection Ovens 3-1Thermo Scientific
Section 3 Unpacking and Installation
The shipping carton should be inspected upon delivery. When received,
carefully examine for any shipping damage before unpacking. If damage is
discovered, the delivering carrier should both specify and sign for the
damage on your copy of the delivery receipt.
Open the carton carefully making certain that all parts are accounted for
before packaging materials are discarded. After unpacking, if damage is
found, promptly report it to the carrier and request a damage inspection
promptly.
Important Failure to request an inspection of damage within a few days
after receipt of shipment absolves the carrier from any liability for
damage.Call for a damage inspection promptly.
Note Disconnect unit from the power source when not in use. s
Set the oven where it is to be operated, in an area free of drafts and strong
vibrations. Do not place on or near a combustible surface or material.
• Use a properly grounded electrical outlet of correct voltage and current
handling capacity.
• Do not remove or modify grounded power plug. Use only properly
grounded outlets to avoid shock hazard.
Location
Electrical
Requirements

3-2 Compact Gravity Convection Ovens Thermo Scientific
Section 3
Unapcking and Installation
Installation 1. Install the shelves on the rack inside the oven.
2. Turn the power switch OFF and plug the oven into a receptacle that
provides the required voltage as indicated on the unit’s nameplate.
3. Install an immersion thermometer (furnished by the user) through the
thermometer grommet and into the thermometer holder.
4. Adjust the immersion depth to 6-7/8” (175mm), measured from the
bulb to the top of the rubber washer.
5. Insert this assembly into the thermometer vent ring that is located on
top of the oven.
Note If the equipment is not used in the manner specified by the
manufacturer, the protection provided by equipment may be impaired. s
Warning 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 that may ignite such materials. Before operating
oven, always observe the following safety precautions:
• Fumes and spillage from acidic solutions cause corrosion of the
stainless steel chamber. Maintain a neutral pH at all times.
• The heater for the oven 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.
Figure 4-2. Thermometer Components
6-7/8" 175 mm
(Top of Oven)
Thermometer Vent Ring
Thermometer Holder
Thermometer Grommet

Compact Gravity Convection Ovens 4-1Thermo Scientific
Section 4 Operation
1. Turn the power switch ON – status lamp will light.
2. Set the control thermostat to obtain the desired temperature. Read the
user-supplied thermometer, not the control dial; the control dial is
graduated from 0 to 10 for REFERENCE PURPOSES ONLY. It is
suggested that a log be made of control settings vs. thermometer
readings to assist in obtaining desired temperatures. However, it is
important to bear in mind that the applicability of such a chart will be
affected by changes in line voltage and ambient conditions.
3. Allow time for the oven to reach its maximum set temperature and to
stabilize.
Warning Do not use in the presence of flammable or combustible
materials or explosive gases. Do not use in the presence of pressurized or
sealed containers - fire or explosion may result, causing death or severe
injury. s
Warning Do not heat any substance above a temperature that will cause it
to emit toxic fumes; death or severe injury may result. s
Caution It is the user’s responsibility to monitor oven action when setting
and maintaining operating temperature; oven failure may occur with
possible property damage and/or injury to personnel. s
Status Lamp
Control Thermostat
Power Switch
ON
OFF
Figure 4-1. Control Panel

4-2 Compact Gravity Convection Ovens Thermo Scientific
Section 4
Operation
Warning To avoid electrical short or shock, do not allow any metal object
to protrude into the space beneath the shelf/heater shield inside the oven.
In addition, do not operate oven with the shield removed. s
Warning Hot Surface At the higher temperatures, the exterior of the oven
and particularly the thermometer vent ring on the top become
uncomfortably warm to the touch. To avoid burns, do not touch these
surfaces. s
Thermometer Vent Ring
Heater Shield
Figure 4-2. Vent Ring and Heater Shield Locations

Compact Gravity Convection Ovens 5-1Thermo Scientific
Section 5 Maintenance
Because of their rugged, simple construction, these ovens require very little
maintenance. Ordinary cleaning will suffice. The bottom shelf that covers
the heater can be removed for easy access to the heater area.
Clean up any spills as soon as possible to prevent materials being baked on
surfaces. When the oven is cool, use a mild soap and water to clean
surfaces. Rinse thoroughly and dry. It is best to avoid highly abrasive
cleaners that can damage the finish of the interior surfaces and shelves.
If the oven fails to heat, there may be several possible causes:
• Oven is not receiving electrical power.
• Heater is burned out.
• Thermostat is malfunctioning.
Have a qualified electrical technician determine the cause of the problem
and make the necessary repairs.Your local Thermo Scientific products
dealer can provide the service and replacement parts needed.
Warning Disconnect from the power supply prior to maintenance and
servicing. s
Note Make no attempt to service or repair a Thermo Scientific product
under warranty before consulting your Thermo dealer. After the warranty
period, such consultation is still advised, especially when the repair may be
technically sophisticated or difficult. If assistance is needed beyond what
the distributor can provide, please call Technical Services. No merchandise
should be returned directly to the factory without obtaining a Return
Materials Authorization (RMA) number from Technical Services. s

Section 6 Replacement Parts
Refer to the Specification Plate for the complete model number, serial
number, and series number when requesting service, replacement parts or
in any correspondence concerning this unit.
All parts listed herein may be ordered from the Thermo Scientific dealer
from whom you purchased this unit or can be obtained promptly from the
factory. When service or replacement parts are needed, check first with
your dealer. If the dealer cannot process your request, then contact our
Technical Services Department.
Prior to returning any materials, please contact our Technical Services
Department for a “Return Materials Authorization” number (RMA).
Material returned without an RMA number will be refused.
Compact Gravity Convection Ovens 6-1Thermo Scientific
DESCRIPTION PART NUMBER
Tension Catch 600-124-00
Handle 560-248-00
Feet 790-225-00
Status Lamp Base 360-233-01
Status Lamp Lens (amber) 360-235-00
Power Switch (120V) SWX143
Power Switch (240V) 440-292-00
Thermometer Grommet 790-247-00
Thermometer Holder 910-039-00
Control Thermostat 920-412-00
Thermostat Knob 560-265-00
Hi-Limit Thermostat 920-413-00
Heaters
PR305225G 340-213-00
PR305220G, PR305220GCN 340-215-00
Shelf Kit 3511-8Q
Ordering Procedures

Section 7 Wiring Diagrams
Compact Gravity Convection Ovens 7-1Thermo Scientific
WH1480X1
WM1480X1
CR1480X1
GRN
BLK
WHT
WM1480X2
ON (I)
CONTROL THERMOSTAT WITH SHAFT