MELAG Type 215 Operating Instructions

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MELAG Type 215 Operating Instructions | Manualzz

Operating Instructions



Models with

Mechanical Air Movement

Type 215 Type 225 Type 255

Sterilization - Disinfection

Sterilization means to free objects from breedable microbes; in the process not only the vegetative, but the resistive forms of germs must be eliminated.

Sterilization by hot air requires a minimum temperature of 180°C (German DIN 58947). During sterilization, spores of type A, B, C, D (according to the German federal public health department) or spores of resistivity level III (according to Prof.

Konrich) have to be killed.

The only result of disinfection is that an object cannot disinfect any more. It is then free from vegetative forms of disease-causing agents, but not free from bacterial spores.

Medical instruments which come into contact with blood or which injures the integrity of human body surface, must therefore always be sterilized before use (tetanus and danger of gangrene infection) – disinfection is not sufficient.

What can be sterilized in hot-air?

In hot-air, it is possible to sterilize objects made of incombustible (inorganic) materials, such as metal, glass, porcelain, stoneware, enamelware, etc., e.g. instruments, syringes, cannulas, and so on (pay attention to the manufacturer's instructions). After use, the instruments, syringes, etc. should immediately be disinfected and then thoroughly be cleaned. Before placing them in the sterilizer, the items have to be dried. Do not place items on cellulose because this might lead to build-up of heat and thus to an obstruction of heat egalization in the apparatus. page 1

1. Operation of the apparatus

Set up the temperature regulator (1) to the sterilizing temperature of 180°C. If the indicated value for temperature is different from the one set up, check for a possible adjustment of the regulating knob (see

"Hints for fault corrections" below).

1.1. Switching on power _______________________________________________

The apparatus' with timer is switched on by adjusting the timer (5) to the time given in the operating time table. The permanent switch (6) of sterilizers of type

215-255 must always be in position "0", if the timer is in operation.

For longer processes (or if the timer is defective), power can be switched on by using switch (5) for the required time. The timer is out of operation. By turning the timer knob counter-clockwise (to the left to "I"), the sterilizer is turned on for permanent operation.

The light of signal lamp (4) indicates that power is on.

The signal lamp (2) optically shows the automatic working procedure of the temperature regulator. It keeps the adjusted temperature to a constant level by turning the heating on or off (not current in general). Lamp (2) goes on and out respectively.

1.2. Switching off power ______________________________________________

The apparatus is automatically switched off at the end of the timer (5).

If a sterilization process was carried out by using the permanent switch (6), set it back to position "0".

Permanent operation of sterilizers of type 71 and type 91 is ended (timer in position "I") by setting the timer knob back to "0". Both signal lamps (2 and 4) go out if power is turned off.

1.3. Mechanical Air Movement __________________________________________

Sterilizers with mechanical air movement have motor-driven fans which are automatically switched on by the turning on of power and switched off respectively.

1.4. Drying procedure _________________________________________________

Set up temperature to 100°C by turning the regulation knob. Shake out pipettes to be dried and lay them in not too wet and – if possible – a little sloping.

Escape of damp air is possible as follows:

As far as sterilizers of type 215-255 are concerned, the door can be engaged into a position of the door hinge where the door will be kept open to enable the drying process.

2. Description of the apparatus

2.1. Front view _______________________________________________________

Type 215 - 255

1 Thermostat

2 Signal lamp heating page 2

3 Thermometer

4 Signal lamp main







5 Timer - On-Off Switch

6 Permanent switch

Operating Instructions

Table of Operating Times



215 / 225 / 255

Maximum load

(without basket/trays)

3,0 kg

Mechanical air movement

70 Min. (3 trays)

85 Min. (6 trays)

The given operating times are based on sterilizations of medical instruments with trays or open containers.

Sterilization processes with closed containers need longer operating times (see below).

Use containers from aluminium not stainless steel container. Determine the additional time by a test run. The safety margin should be 10%.

2.2. German VDE-requirements _________________________________________

In accordance with the valid VDE-requirements, this autoclave is not suitable for areas with danger of explosion.

It may be repaired only by the manufacturer or a licensed service unit.

3. Attention! Warning

• Before opening the door switch off the appliance, either using the main switch (6) or by turning the time switch (5) to “0”. The signal lamp (4) is no longer on.

• Be careful when loading and unloading the hot sterilizer. Trays and sterilised items are hot!

• The ventilator only comes to rest some 45 secs after switching off the appliance.

• During and after the sterilisation process some parts of the housing may become very hot and could cause burns. Danger!

• This appliance is not suitable for the sterilization of liquids and for the warming up of rinse solvents !

4. Attention! Misoperation

The hot-air sterilisszation method is fully accepted

(German DIN 58947). Nevertheless, this method is still criticized because bacteriological examinations about hot-air sterilizers still show a growth of testing germs. A more detailed examination demonstrates that this fact is mostly caused by misoperation.

5. Fault No. 1: Operating time too short!

The operator assumes the correct fact that a temperature of 180°C for a period of 30 minutes takes effect on the items to be sterilized. But the fault lies in the exclusive observation of the thermometer. As soon as the thermometer shows a temperature of

180°C, the operator wrongly begins to count the 30 minute period after which the sterilizer can be switched off. This procedure only considers the preheat time but not the equalization time. It is wrong to assume that the killing time starts immediately after the conclusion of the pre-heat time. Between killing and pre-heat time, the operator has to take the equalization time into account. This is the time needed for the required temperature reaching all places of the apparatus and of the items to be sterilized. Only after conclusion of the equalization time the killing time begins which endures 30 minutes

(with 180°C). This period contains an extra charge for safety (German DIN 58947, part 5).

All these conclusions of times are included in the operating times given above (see table). The operating times are based on sterilizations of medical instruments under use of trays or open containers.

Sterilization processes with closed containers need longer operating times. If the items are sterilized in closed cassettes made of aluminium with thin walls, the operating times have to be elongated for 15 minutes. On principle, we recommend not to use closed containers. For example, we have measured a temperature of only 160°C inside of plates after 3½ hours! page 3

6. Hints about fault corrections

6.1. Timer does not automatically switch off power ________________________

If the timer is defective, the sterilizer can still be operated in a half-automatic way with the help of the permanent switch (6). Before exchange of the timer, it is absolutely necessary to pull out the main plug.

Loosen the screw of the timer knob and remove the knob. Unscrew the front scale plate and remove it with care. Then remove the stick hulls of the cable ends from the flat plugs of the timer and unscrew the timer from the front scale plate. Connect and install the new timer in the same way.

A new timer can only be ordered at specialist shops.

For quick completion, it is necessary to know the type of sterilizer and its work number.

6.2. Temperature set up with the regulation knob does not tally with indication of the thermometer _______________________________________

Hot-air sterilizers from MELAG are delivered with temperature calibrated at 180°C by adjusting the regulator axis so that the thermometer really shows a value of 180°C. Then the thermostat knob is sticked on the axis so that the white indicator of the knob points to the 180°C- mark on the scale. In this position, the thermostat knob is fixed to its axis by fastening the clamp screw.

If the thermostat knob is unintentionally be turned with force beyond the resistance due to improper treatment, e.g. during cleaning or unpacking of the gadget, or if the screw is loosened in the taper, the knob can slip on the regulator axis. Respectively, the real temperature inside the vessel (indicated on the thermometer) is different from the one set up on the regulator scale.

A quick correction can easily be achieved by turning the thermostat knob either little clockwise in order to obtain a higher temperature, or counter-clockwise for lower temperature. Provisional markings on the scale will help adjustment.

A correct calibration is carried out as follows:

Remove the grey cap from the thermostat knob.

After loosening the clamp screw below, the knob can be removed from the axis. Close the door and switch on the sterilizer. Now adjust the temperature regulator by turning the axis (perhaps with small pliers) so that the thermometer shows the desired temperature (e.g. 180°C) after conclusion of pre-heat and equalization time. Put the thermostat knob back on the axis so that the white indicator points to a value on the scale which agrees with the temperature shown on the thermometer. Finally screw the knob's screw tight without changing the position of the axis.

6.3. The appliance does not heat up _____________________________________

If your hot air steriliser does not work, check the internal fuses. To change fuses, first disconnect the appliance from the mains power supply. Press down the tongue on the fuse container on the rear side of the oppliance and pull the container out.

Inspect the fuses and exchange if necessary.

If the signal lamp (4) does not light up to show that the power is on, check the cable, power socket, and mains fuse.

If the signal lamp (4) lights up but not signal lamp

(2), check the setting of the control knob (see 1. above).

7. Appendix

7.1. Spare parts ______________________________________________________

Article No. Description

32985 door seal (type 215-225)


32890 door seal (type 255) thermostat



16450 timer thermometer mains fuse 6,3A 2x page 4

Rev. 2 – 99/0233 BA_GB_215_225_255.doc


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