Eschmann Little Sister 3 Service manual
SES LS3
A UTOCLAVE
Technical Manual
699346
ST-TM4e
Introduction
Technical
description
Read these Instructions before use
Keep these Instructions in a safe convenient place for future reference. Read in conjunction
with the Publications detailed on page 8.
Maintenance
Illustrated
parts list
Eschmann After Sales Service Department
The Eschmann After Sales Service Department is staffed and equipped to provide advice and
assistance during normal office hours. To avoid delays when making enquires, please quote the
Model and Serial Number of your autoclave.
For further information visit www.eschmann.co.uk
All correspondence relating to the after sales service of Eschmann Equipment to be addressed to :
UK Customers
Eschmann Equipment, Peter Road, Lancing, West Sussex BN15 8TJ, England.
T el: +44 (0) 1903 765040. Fax: +44 (0) 1903 762006.
Overseas Customers
Contact your local distributor. In case of doubt contact Eschmann Equipment.
Trade marks
The ESCHMANN name and logo are registered trade marks of Eschmann Holdings Limited .
“Eschmann Equipment” is a trading name of Eschmann Holdings Limit ed.
“Little Sister 3” and “SES” are trade marks of Eschmann Holdings Limited.
Copyright © 2003
All rights reserved. This booklet is protected by copyright. No part of it may be reproduced, stored in a
retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying,
recording or otherwise without written permission from Eschmann Holdings Limited.
The information in this publication was correct at the time of going to print. The Company, however,
reserves the right to modify or improve the equipment referred to.
Technical Manual
ST-TM4e November 2002
SES Little Sister 3 - Technical Manual
CONTENTS
Page
Technical data (Standard) .............................................................................................. 6
Technical data (Long) .................................................................................................... 7
INTRODUCTION
General .......................................................................................................................... 8
Associated publication .................................................................................................. 8
Note to readers .............................................................................................................. 8
Servicing........................................................................................................................ 8
TECHNICAL DESCRIPTION
General .......................................................................................................................... 9
Operating features ......................................................................................................... 9
Description of operation cycle..................................................................................... 15
Display messages ........................................................................................................ 17
Error indication ........................................................................................................... 18
General ............................................................................................................ 18
Overheating ..................................................................................................... 19
MAINTENANCE
Fault diagnosis............................................................................................................. 18
Removing cover .......................................................................................................... 22
Refitting cover............................................................................................................. 22
Part replacement and adjustment................................................................................. 22
Fuses ............................................................................................................... 22
Fusible link...................................................................................................... 23
Transformer..................................................................................................... 23
Controller ........................................................................................................ 23
Pressure door lock ........................................................................................... 23
Air valve.......................................................................................................... 24
Door interlock switch...................................................................................... 24
Solenoid door lock .......................................................................................... 25
Heater cut-out or cycling thermostat ............................................................... 25
Temperature sensor(s) ..................................................................................... 25
Fill and discharge valves................................................................................. 26
Reservoir float switch ..................................................................................... 26
Solid state relay ............................................................................................... 26
Mechanical relay ............................................................................................. 26
Heater .............................................................................................................. 26
Voltage regulator ............................................................................................. 27
Door seal ......................................................................................................... 27
Pressure gauge................................................................................................. 28
Discharge line filter ......................................................................................... 28
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SES Little Sister 3 - Technical Manual
CONTENTS
Page
Special operating modes.............................................................................................. 29
Demonstration mode ....................................................................................... 29
Engineering mode ........................................................................................... 30
Set-up mode .................................................................................................... 31
Errors and error clearing ................................................................................. 32
Special button usage ............................................................................... 32
Autocheck ............................................................................................... 32
Routine calibration procedure ..................................................................................... 33
Controller setting......................................................................................................... 35
Test procedures............................................................................................................ 36
Safety valve..................................................................................................... 36
Heater cut-out.................................................................................................. 37
ILLUSTRATED SPARES LIST
LIST OF ILLUSTRATIONS
Fig.
1 SES Little Sister 3 autoclave............................................................................. 5
2 SES Little Sister 3 autoclave - general view and door mechanism................. 10
3 SES Little Sister 3 autoclave - water/steam pipelines and valves................... 12
4 SES Little Sister 3 autoclave - heater and process controls ............................ 14
5 Controller board .............................................................................................. 27
6 Filter unit - disassembly .................................................................................. 28
7a SES Little Sister 3 autoclave - spares items (general) .................................... 38
7b SES Little Sister 3 autoclave - spares items (pipelines and valves)................ 40
7c SES Little Sister 3 autoclave - spares items (heater and process controls)..... 42
8 System circuit diagram.................................................................................... 45
TABLES
Table
1 Fault Diagnosis ............................................................................................... 18
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SES Little Sister 3 - Technical Manual
Fig. 1 Little Sister 3 Autoclave
ST-TM4e Page 5 of 45
SES Little Sister 3 - Technical Manual
TECHNICAL DATA (Standard)
Electrical Data
Supply .......................................240V, or 220V, or 110V a.c., 50/60 Hz
Loading
240V ................................ 2kW at 8.4A
220V ................................ 2kW at 9.0A
110v .................................1.3kW at 11.5A
Fuses
240V ................................ F10A, 1 in (x2) F400mA, 20mm (xl)
220V ................................ F13A, 1 in (x2) F400mA, 20mm (xl)
110V.................................F16A, 1¼ in (x2) F800mA, 20mm (xl)
Controller board...............F2A, 20mm
Safety Category ......................... Type B (as defined by IEC601-1)
.........................................For use with alternating current
Sterilizing Data
Sterilizing time ..........................At 134/138°C - 3 minutes 20 sec
At 121/124°C - 15 minutes
Typical overall time...................At 134°C- 13 minutes )
(without drying) At 121°C - 24 minutes )
Drying time ...............................Up to 17 minutes after sterilizing
(when selected)
Operating pressure .................... 138°C-2.40 bar (34.80 lbf/in2)
134°C-2.03 bar (29.51 lbf/in2)
124°C-1.25 bar (18.17 lbf/in2)
121°C-1.04 bar (15.12 lbf/in2)
Water reservoir capacity ............ 2.0 litre (3.5 pint)
Dimensions and Weights
Dimensions (W x D x H) ..........460mm (18.12in) x 461 mm (18.16in) x 360mm (14.18in)
Chamber ....................................200mm (7.88in) Diameter x 348mm (13.7in) Length max.
Trays (L x W x D) .....................282.6mm (11.13in) x 183mm (7.2in) x 17mm (0.67in)
2kW
Weight (approx)
Net ...................................27.5 kg (61 lb)
Shipping ........................... 32.0 kg (71 lb)
Tray loading .....................2.0 kg (4.4 lb) per tray
Symbols
.........................................For use with alternating current
.........................................Hazard warning (overheating)
134°C ....................................Sterilizing cycle without drying phase
134°C ..................................Sterilizing cycle with drying phase
Page 6 of 45 ST-TM4e
SES Little Sister 3 - Technical Manual
TECHNICAL DATA (Long)
Electrical Data
Supply .......................................240V, or 220V a.c. 50/60 Hz
Loading
240V ................................ 2.75kW at 11.5A
220V ................................ 2.75kW at 12.5A
Fuses
240V ................................ F13A, 1 in (x2) F400mA, 20mm (xl)
220V ................................ F13A, 1 in (x2) F400mA, 20mm (xl)
Controller board...............F2A, 20mm
Safety Category ......................... Type B (conforms to BS5724 and IEC601-1)
.........................................For use with alternating current only
Sterilizing Data
Sterilizing time ..........................At 134/138°C -3 minutes 20 sec
At 121/124°C - 15 minutes
Typical overall time...................At 134°C - 13 minutes )
(without drying) At 121°C - 24 minutes )
Drying time ...............................Up to 17 minutes after sterilizing cycle
(when selected)
Operating pressure .................... 138°C-2.40 bar
134°C-2.03 bar
124°C-1.25 bar
121°C-1.04 bar
Water reservoir capacity ............ 2.0 litre
Dimensions and Weights
Overall (L xW x D) ...................650mm x 460mm x 360mm
Chamber ....................................200mm Diameter x 500mm Depth
Trays (L xW x D) ......................457mm x 180mm x 24mm
Weight (approx)
Net ...................................35.5 kg
Shipping ........................... 40.0 kg
Tray loading .....................3.0 kg per tray
2.75kW
Symbols
.........................................For use with alternating current
.........................................Hazard warning (overheating)
134°C ....................................Sterilizing cycle without drying phase
134°C ..................................Sterilizing cycle with drying phase
ST-TM4e Page 7 of 45
SES Little Sister 3 - Technical Manual
INTRODUCTION
GENERAL
1. This publication contains technical description and maintenance procedures for the SES Little
Sister 3 autoclave.
2. Separate installation and users instructions are contained in the SES Little Sister 3 Operators
Handbook (Publication No. ST-0H3).
3. The SES Little Sister 3 is a portable electrically operated steam autoclave suitable for the sterilization
of unwrapped metal instruments and utensils.
4. The sterilizing cycle proceeds automatically once it has been initiated by pressing a single
programme selection button.
ASSOCIATED PUBLICATION
5. SES Little Sister 3 Operators Handbook................................... ST-0H3
NOTE TO READERS
6. The information contained in this publication was correct at the time of printing. The Company,
however, reserves the right to modify or improve the equipment referred to.
SERVICING
7. Ensure that routine servicing is carried out at regular intervals by either Eschmann trained personnel
or suitably trained hospital engineers only, otherwise warranty for equipment could be infringed.
DO KEEP INSTRUCTION AND SERVICE MANUALS READILY ACCESSIBLE
FOR REFERENCE PURPOSES PRIOR TO AND DURING OPERATION,
CLEANING, STERILIZING AND SERVICING THE EQUIPMENT.
NOTE: CONTAMINATED DOOR SEAL
When using lubricated dental hand pieces, the reservoir water should be changed every week to
obviate contamination of the door seal and other rubber components used in the pressure system.
(e.g. safety valve seals and pressure door lock diaphragms).
Page 8 of 45 ST-TM4e
SES Little Sister 3 - Technical Manual
TECHNICAL DESCRIPTION
GENERAL
1. The SES Little Sister 3 is a portable steam autoclave heated by a single element and can be
manufactured to suit any of the mains supplies indicated under TECHNICAL DATA.
2. The unit is electronically controlled and offers a selection of sterilizing programmes as follows:
134°C without drying
121°C without drying
134°C with drying
121°C with drying
For sterilizing pressures and sterilizing/drying times refer to TECHNICAL DATA.
3. The required sterilizing programme is selected and initiated by pressing the appropriate programme
button on the front panel of the unit, following which the sterilizing/drying cycle proceeds automatically
until complete.
4. Indication of cycle status is provided by a digital display. If an error should occur during a cycle
this also is indicated by digital display.
OPERATING FEATURES
5. The following pieces of equipment, designed for control and/or protection, are incorporated in the
SES Little Sister 3:
(1) PRESSURE GAUGE (Fig. 3 item 3). This is used to indicate pressure inside chamber.
(2) PROCESS DISPLAY WINDOW (Fig. 2 item 2). The digital display indicates temperature inside
chamber and also provides simple messages for the user which indicate stages through the cycle
and error conditions, should any occur.
(3) FOUR PROGRAMME SELECTOR BUTTONS (Fig. 4 item 15). These are used to select and
initiate a particular cycle. They can also be used to place the autoclave in the Demonstration or
Engineering mode as described later.
(4) ORANGE LIGHT EMITTING DIODES (LEDs) (Fig. 4 item 16). There are four LEDs and
these are used primarily to indicate the point at which the required sterilizing cycle can be selected
and initiated and, when this has been done, to indicate which particular cycle is in progress.
(5) POWER ON/OFF SWITCH (Fig. 4 item 17). This switch controls mains power supply to the
unit.
(6) OVERHEAT WARNING LAMP (Fig. 4 item 18). The illumination of this red lamp indicates
that the protective thermal fuse (Fig. 4 item 7) has operated.
(7) DOOR LATCHING HANDLE (Fig. 2 item 4). This handle operates the door mechanism to
secure the door in the locked position against the chamber mouth.
(8) DOOR SECONDARY LATCH (Fig. 2 item 6). This engages a safety catch to ensure the door
does not fly open should there be a slight residual pressure in the chamber when the door latching
handle is operated. It is also used to retain the door slightly open during the drying part of the
cycle.
ST-TM4e Page 9 of 45
SES Little Sister 3 - Technical Manual
1. Pressure display window 12. Aerotight nut
2. Process display window 13. Door safety catch
3. Control panel 14. Pressure chamber
4. Door latching handle 15. Work tray
5. Pressure door 16. Reservoir access cover
6. Secondary door latch 17. Reservoir
7. Door cover 18. Cover screw (self-tapping)
8. Seal spinning 19. Unit cover
9. Seal retaining disc 20. Front panel
10. Door seal 21. Chassis
11. O-ring
Fig. 2 Little Sister 3 Autoclave - general view and door mechanism
Page 10 of 45 ST-TM4e
SES Little Sister 3 - Technical Manual
TECHNICAL DESCRIPTION (contd)
(9) DOOR INTERLOCK SWITCH (Fig. 4 item 6). This is used to signal to the controller that the
door is correctly closed. This is operated via a simple adjustable mechanism and should operate
just as the door becomes fully closed.
(10) PRESSURE DOOR LOCK (Fig. 3 item 7). This is a safety device designed to ensure that the
door cannot be opened if the internal chamber pressure exceeds approximately 0.2 bar (3.0 lb/
in2). The device comprises a spring-loaded plunger driven by the chamber pressure via a rubber
diaphragm.
(11) SOLENOID DOOR LOCK (Fig. 4 item 25). This prevents the door being opened inadvertently
by the operator, once the cycle has been started. The lock holds the door closed until sterilizing
cycle is complete. It will also retain the door closed under all fault conditions. Since absence of
power to the unit constitutes a fault this also means that the unit power switch must be switched
on in order to open the door.
Note: If it is necessary to override the electrical door lock to clear an error code, this is done by
switching off the power switch then, after a few seconds, switching it back on again while
holding in any one of the programme selector buttons on the front panel.
(12) WATER RESERVOIR (Fig. 2 item 17). This is used to hold distilled, deionized or purified water
before being admitted to the chamber via the water fill valve and to receive the hot water and
steam vapour emitted from the chamber towards the end of the cycle, via the discharge valve.
(13) RESERVOIR FLOAT SWITCH (Fig. 3 item 12). The water reservoir is fitted with a float switch
which will prevent the cycle being started if there is insufficient water in the reservoir to complete
a chamber fill. LoH2O will be displayed should this occur.
(14) HEATING ELEMENT (Fig. 4 item 1). This consists of a single immersion type element inside
the chamber. This is rated at 2.75kW on 200/240V a.c. and is controlled via the solid state relay
and heater thermostat (see Electrical Data - Loading).
(15) SOLID STATE RELAY (Fig. 4 item 24). This is switched on and off by the controller as necessary
and is the means of controlling the heater output. The solid state relay is mounted on the internal
bulkhead on a PCB and is rated at least 25A, 400V (repetitive reverse blocking voltage) or such
as to be suitable for use on a 240V a.c. supply.
(16) MECHANICAL RELAY (Fig. 4 item 8). This relay isolates the heater circuit from the electrical
supply prior to cycle start and following cycle completion, to give additional protection.
(17) HEATER CUT-OUT (Fig. 4 items 22 and 23). The heater cut-out is connected in series with a
heater thermostat and the solid state relay to the heating element. It is operated by a fluid-filled
capsule clamped to the heating element which will cause the cut-out device to operate if heater
surface temperature exceeds approximately 250°C. The cut-out is of the manual reset type and
will thus remake electrically if the reset button at the rear of the cabinet is pressed, when the
temperature has dropped. This device is used to protect the heater and the autoclave.
(18) HEATER CYCLING THERMOSTAT (Fig. 4 items 2 and 3). This thermostat is connected in
series with a solid state relay to the heating element. It is operated by a fluid-filled capsule
clamped to the heating element which will cause the thermostat switch to operate if the heater
surface temperature exceeds approximately 175°C. The thermostat switch is of the self-resetting
type and will thus remake when the temperature drops. Operation of the heater cycling thermostat
during the drying phase of the cycle is quite normal.
ST-TM4e Page 11 of 45
SES Little Sister 3 - Technical Manual
1. Water fill valve 8. Reservoir drain tube
2. Discharge valve 9. Drain tap
3. Pressure gauge 10. Filter unit
4. Chamber manifold 11. Non-return valve
5. Safety valve 12. Reservoir float switch
6. Test Valve 13. Coil
7. Pressure door lock
Fig. 3 Little Sister 3 Autoclave - pipelines and valves
Page 12 of 45 ST-TM4e
SES Little Sister 3 - Technical Manual
TECHNICAL DESCRIPTION (contd)
(19) FUSIBLE LINK (Fig. 4 item 7). This is connected so as to remove power from the heater if a
serious overheating condition should occur. Note however that operation of this device is unlikely
to occur since the heating element is already protected by the heater cut-out. The fusible link
thus acts as a last resort device and is non-resetting.
(20) FUSES. The unit is provided with four fuses as follows:
(a) Three fuses on the rear panel of the cabinet (Fig. 4 items 9 and 10) rated as shown under
TECHNICAL DATA. The two larger fuses are connected into the supply lines to the unit.
The small fuse protects the primary circuit of the transformer.
(b) A fourth fuse, situated on the printed circuit board (Fig. 5 item 5) and rated at 2A, protects
the secondary circuit of the transformer and parts of the controller.
(21) TRANSFORMER (Fig. 4 item 11). This converts the incoming mains voltage to 20V a.c. to
operate the controller and the water fill and discharge valves. It is rated at 20VA. A thermal fuse
is fitted in the secondary winding, this is not resettable and therefore a new transformer would be
required. CHECK FOR SHORT CIRCUIT BEFORE FITTING.
(22) WATER FILL VALVE (Fig. 3 item 1). This valve is used to control the water filling sequence. It
is electrically operated from a 24V d.c. supply which is generated and signalled from the controller.
(23) DISCHARGE VALVE (Fig. 3 item 2). This valve is used principally at the end of the sterilizing
cycle to allow water and steam from the chamber to pass back into the reservoir. It is also
operated at various other times during the cycle. The valve is electrically operated from a 24V
d.c. supply generated within the controller.
(24) AIR VALVE (Fig. 3 item 6). At the start of any cycle the chamber is full of air and for a satisfactory
result almost all of this has to be removed. In the SES Little Sister 3 this is accomplished by
means of a small air valve. This valve contains a ball and spring which allows air displaced by
the steam generated in the chamber to pass out into the reservoir. Once steam starts to pass by the
ball, the ball then lifts and seals. A small bleed remains, however, and it is quite normal for
small quantities of steam to escape into the reservoir throughout the cycle.
(25) SAFETY VALVE (Fig. 3 item 5). This is mounted on the manifold at the rear of the chamber and
is factory set to lift at 2.6 bar in order to release excess pressure from within the chamber. It is a
primary safety device and should not be readjusted.
(26) TEMPERATURE SENSOR (Fig. 4 item 4). This is used to sense the chamber temperature and
is mounted on the manifold in a position where it is exposed to a small volume of steam bled
through the air valve. The temperature sensor comprises a small electronic circuit (Analogue
Devices type AD590JH) which produces a current proportional to temperature. This device with
its associated leads, mounting plate, spring and connector together form a single assembly. The
sensor is used to control the temperature within the chamber.
(27) TEMPERATURE SENSOR (Fig. 4 item 21). This is the same device as described under sub-
para. (26) and senses the chamber temperature in the same manner. This sensor, however, is used
to display the chamber temperature and has no control function.
Note: Items 4 and 21 of Fig. 4 are identical. It is their point of connection on the controller board
which determines either control or display function.
ST-TM4e Page 13 of 45
SES Little Sister 3 - Technical Manual
1. Heating element 13. Terminal block
2. Sensor (cycling thermostat) 14. Power supply cable
3. Switch (cycling thermostat) 15. Programme selector buttons
4. Temperature sensor (chamber control) 16. Light emitting diodes (LEDs)
5. Water level sensor 17. Power on/off switch
6. Door interlock microswitch 18. Overheat warning lamp
7. Thermal fuse 19. Thermocouple entry port
8. Mechanical relay 20. Test Port
9. Fuses (10A, 13A or 20A) 21. Temperature sensor (display)
10. Fuse (400mA or 800mA) 22. Sensor (heater cut-out)
11. Transformer 23. Switch (heater cut-out)
12. PCB (controller) 24. Solid state relay
25. Solenoid door lock
Fig. 4 Little Sister 3 - Heater and process controls
Page 14 of 45 ST-TM4e
SES Little Sister 3 - Technical Manual
TECHNICAL DESCRIPTION (contd)
(28) THERMOCOUPLE ENTRY PORT (Fig. 4 items 19 and 20). This can be used to introduce a
thermocouple into the chamber drain line to allow the operating temperature to be measured
and adjusted if necessary. To ensure probe is not touching the capillary tube or the bottom of the
hole, withdraw probe approximately 3mm from the stop position.
(29) WATER DRAIN PIPE (Fig. 3 items 8 and 9). This provides a convenient means of emptying the
reservoir for cleaning or prior to transportation.
(30) CONTROLLER (Fig. 4 item 12). The SES Little Sister 3 is provided with a fully integrated
microprocessor-based controller. The controller handles every aspect of management of the
machine which includes operation and control of the digital display, the light emitting diodes
and response to the programme selection push buttons. The controller receives information from
the temperature sensor and from the door interlock switch and is able to detect a variety of errors
and the times relative to the cycle run when these occur. In addition to controlling the autoclave
in the user mode, the controller also supports a demonstration and an engineering mode (see
SPECIAL OPERATING MODES). The controller operates the heater via the solid state relay
and also controls the operation of the water fill and discharge valves. A detailed knowledge of
the operation of the controller is not necessary in order to service the autoclave; it is best regarded
as a replaceable sub-assembly and should only be changed as a last resort.
(31) CYCLE COUNTER. The cycle counter displays the number of completed cycles to date for
three seconds when power is first switched on, then for one second every fifteen seconds at other
times. After commencement of a cycle the counter display will include that cycle in the total
count.
DESCRIPTION OF OPERATION CYCLE
6. A detailed knowledge of every aspect of the operation of the SES Little Sister 3 is not necessary in
order to be able to repair it effectively; nevertheless, a basic understanding of the various processes of the
unit operation which take place during a cycle can be useful.
Unit Operation
7. Power to the unit is switched on by selecting the power switch 0-I to I, there now follows a
single high-pitched audible signal accompanied by the display test door flashing. Alternatively open
door to proceed, LS3 will now be displayed followed by door. If the door is not closed the display will
show LS3 then door when power is switched on.
8. After the work trays have been placed in the chamber and the door closed, the discharge valve is
opened, rEAdy is displayed and LEDs on the programme selector panel flash on and off to indicate that
a programme from those available* can now be selected and initiated by pressing one of the programme
selector buttons.
* The unit is normally preset to offer a choice of two programmes at 134°C. This unit can be
customised to suit the sterilizing requirements. (i.e. single temperature, part or whole programme).
9. When the door is closed, with power switched on, this is sensed by the controller via the door
interlock switch. If any attempt is made to open the door once the cycle has commenced, the error display
Err 2 will appear, accompanied by an audible signal. Under these circumstances it is necessary to secure
the door and cancel Err 2 display (see para. 25) and then re-start cycle.
ST-TM4e Page 15 of 45
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