This document describes the Miele Professional Washer-Disinfector G 7891, a machine designed for cleaning, rinsing, thermally disinfecting, and drying a wide range of reusable medical devices, particularly dental instruments. It is intended for professional use in dental surgeries and other medical facilities where reproducible results and manual processing are to be avoided. The machine complies with EN ISO 15883 for validation purposes.
Function Description
The washer-disinfector performs a multi-stage process to ensure thorough cleaning and disinfection. This includes pre-wash, main wash, rinses, and drying. The machine is capable of processing various types of instruments, including dental instruments, suction apparatus, and transfer instruments. It uses chemical agents for cleaning, neutralising, and rinsing, which are dispensed automatically during the programme. Thermal disinfection is achieved at 90°C (+5°C, -0°C) with a holding time of 5 minutes, making it suitable for deactivating the HBV virus. The machine can be programmed with various settings to suit different types of loads and soiling levels.
Important Technical Specifications
- Dimensions: Height with lid: 85 cm, Height without lid: 82 cm, Width: 60 cm, Depth: 60 cm, Depth with door open: 120 cm.
- Weight (net): 70 kg.
- Voltage, connected load, fuse rating: See data plate.
- Mains cable: Approx. 1.8 m.
- Water temperature: Cold water: Max. 20°C, AD water connection: Max. 60°C.
- Static water pressure: Max. 1000 kPa (10 bar).
- Minimum flow pressure: Cold water connection: 100 kPa, AD water connection: 60 kPa.
- Recommended flow pressure: Cold water connection: ≥ 250 kPa, AD water connection: ≥ 150 kPa.
- Delivery head: Min. 0.3 m, max. 1 m.
- Ambient temperature: 5°C to 40°C.
- Relative humidity maximum: 80% for temperatures to 31°C, 50% for temperatures to 40°C.
- Altitude: Max. 1500 m.
- Degree of soiling: P2 (according to IEC/EN 61010-1).
- Protection category (according to IEC 60529): IP20 (Dust permeation).
- Noise level in dB (A): < 70.
- Sound level LpA during cleaning and drying phases: See data plate.
- Test marks: VDE, radio interference suppression.
- CE mark: MDD-Guidelines 93/42/EWG, Class IIb.
- Water softener: Programmable, with settings from 0 to 60 °dH (0 to 70 mmol/l). The "0" setting is only for machines which do not have a water softener. Factory default setting is 19 °dH (3.4 mmol/l).
- Rinsing agent reservoir: Holds approx. 180 ml. Dosage adjustable from 1 to 6 (1-6 ml), factory set to 3 (3 ml).
- Drying unit: Features an original Miele HEPA filter (classification 12).
- Water connection: Standard connection to an AD water supply of 0.6 - 10 bar (60 - 1000 kPa). Water pressure (flow rate) is below 1.5 bar (150 kPa).
- Drainage: Fitted with a non-return valve. Should be connected to a separate drainage system on-site. Drain connection point sited between 0.3 m and 1 m above the lower edge of the machine. Minimum drainage flow of 16 l/min. Drain hose approx. 1.4 m long, 22 mm internal diameter.
Usage Features
- Operation: The machine is switched on via the I-0 switch. Programmes are selected using a rotary selector. The display shows actual temperature, elapsed time, and active block.
- Door: Features an electric door lock. Can be opened via a door release button. An emergency release is available in case of power failure.
- Water Softener: Essential for optimal cleaning results, especially in areas with hard water. The water softener needs to be programmed according to the local water hardness. Salt reservoir needs to be filled with special coarse-grained reactivation salt (1-4 mm). An "Add salt" indicator light signals when refilling is required.
- Chemical Agent Dispensing:
- Rinsing Agent: Dispensed automatically. Reservoir capacity approx. 180 ml. Dosage can be set from 1 to 6 ml. An indicator light signals when refilling is needed.
- Neutralising Agent: Used in the interim rinse stage of some programmes to prevent discolouration and rust spots. Neutralises residues of alkaline cleaning agents. Dispensed automatically via DOS 3. The dispensing system container needs to be filled and vented. An indicator light signals when refilling is needed.
- Liquid Cleaning Agent: Can be dispensed via the optional DOS module K 60 (DOS 1). The dosage concentration can be set. The dispensing system needs to be vented.
- Powder Cleaning Agent: Placed in the powder cleaning agent dispenser before every programme (except PRE-RINSE and DRAIN).
- Baskets and Inserts: Various inserts and special baskets are available for a wide variety of instruments and utensils. The top basket is height adjustable. Specific holders are available for dental hand pieces, contra angles, and mouth rinse beakers.
- Programmable Functions: Allows for customisation of various parameters, including buzzer settings, wash parameters (temperature, temperature holding time), and drying parameters (temperature, drying time). Factory default settings can be reset.
- Process Documentation: The washer-disinfector is capable of documenting processing procedures. Data can be transferred via a serial interface (RS 232) to documentation software or a printer. Reports include date, machine number, programme start/end, blocks used, dispensing system dosage, temperature values, fault messages, and salt status.
Maintenance Features
- Periodic Checks: Recommended every 1000 operating hours or every 12-18 months by a Miele approved service technician. Checks include electrical safety, door mechanism, screw connections, water inlet/drainage, dispensing systems, spray arms, filter combination, sump, baskets, inserts, and drying unit.
- Process Validation: The standard of disinfection must be confirmed by the user as a routine matter. In the UK, safety checks should be carried out every 3 months by a Miele approved service technician.
- Routine Checks: Before each working day, the user must carry out a number of routine checks, including all filters in the wash cabinet, spray arms, wash cabinet and door seal, dispensing systems, and baskets/inserts.
- Cleaning the Filters: The coarse filter and micro-fine filters in the wash cabinet base must be regularly cleaned to prevent clogging.
- Cleaning the Spray Arms: Should be checked daily and cleaned if blocked by particles.
- Cleaning the Control Panel: Should be cleaned using a damp cloth and a proprietary cleaning agent for plastic surfaces.
- Cleaning the Wash Cabinet and Door Seals: The wash cabinet is generally self-cleaning, but deposits may occur. Door seals should be cleaned regularly.
- Drying Unit (TA) - Maintenance: The HEPA filter must be changed when "SF2" appears in the display. The operating hours counter for the filter needs to be reset after changing.
- Cleaning the Drain Pump and Non-Return Valve: If water is not pumped away, the drain pump or non-return valve may be blocked and need cleaning.
- Cleaning the Filters in the Water Inlet: Filters in the screw connection of the water inlet hose should be cleaned if insufficient water flows into the wash cabinet.
- Problem Solving Guide: Provides a comprehensive list of faults, possible causes, and remedies, including issues with the machine not starting, programme cancellation, chemical agent dispensing, water inlet/drainage, heating, cleaning agent residue, noise, corrosion, and unsatisfactory cleaning results.
- Thermal Cut-Out: The machine has a resettable heater limiter that will shut off the elements in the event of over-heating.
- After Sales Service: Contact Miele Service Department for any faults that cannot be remedied by the user.
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