How to clean a commercial dishwasher

2 April 2020 - manutenzione lavastoviglie

How to maintain your industrial dishwasher in good health

The basic maintenance of an commercial dishwasher consists of a series of operations that can be easily carried out even by non-technical people.

These are simple tasks & activities to be performed at regular intervals that can exponentially increase the average life of your commercial dishwasher and maintain high standards of hygiene and dishwashing results over time.

Before carrying out any maintenance, wait until the end of the washing cycle, drain the water completely, unplug the dishwasher from the power outlet and close the external water valve. Also, ensure that the maintenance area around the machine is well enlightened.

Personal protective equipment (PPE) must be worn during machine maintenance operations, such as:

  • Clothing: complying with the essential safety requirements in force in the work environment where it will be used, capable of protecting the body from hot water and detergents
  • Gloves: When working in areas with loads, mechanical parts, detergents and parts that can reach high temperatures, it is necessary to use CE-marked gloves as PPE that protect against all the risks just analyzed
  • Safety shoes: These are required in all work where there is a risk of a potentially hazardous general unit falling

Before going through all the operations that allow the industrial dishwasher to keep in good conditions, let’s list what the preliminary activities are for a perfect installation of the machine.

Industrial dishwasher installation and fault prevention

Placing the dishwasher

  • Ensure that there are no objects and materials in the installation area, or, if present, sufficiently protected, that can be damaged by water vapor that may come out of the machine during operation.
  • Before installing the dishwasher, prepare the electrical supply, water supply and drainage systems in the room. In the case of built-in installation, a space of at least 20 mm must be provided between all walls of the built-in and the walls and top of the dishwasher.
  • The floor or the built-in must be dimensioned taking into account the total weight of the dishwasher.
  • To ensure stability, install and level the machine on its four feet.
  • This appliance is only suitable for a fixed connection, different installation solutions must be agreed and approved by the manufacturer.
  • Remove the protective film from the body before starting to use the dishwasher.

Connection to the power supply

  • The electrical system must have an omnipolar main switch, disconnecting all contacts including the neutral, with a distance between open contacts of at least 3 mm and with a safety magneto-thermal switch or coupled with fuses, to be sized or calibrated in accordance with the power rating indicated on the machine’s rating plate.
  • The main switch must be located on the power line near the installation and must only serve one piece of appliance at a time.
  • The mains voltage and frequency must correspond to those indicated on the rating plate.
  • There must be an effective earthing system, in accordance with current prevention regulations, for the safety of the operator and the equipment.
  • The power cable, exclusively type H07RN-F, must not be pulled or squeezed during normal operation or maintenance.
  • The appliance must also be included in an equipotential system, the connection of which is made by means of a screw marked with the symbol
  • The equipotential earth conductor must have a cross-section complying with the requirements of the regulations in force and in any case not less than 10 mm².
  • Respect the polarities indicated in the circuit diagram.
  • Refer to the circuit diagram for further information.
  • It is forbidden to use multiple sockets, adapters, cables of unsuitable type and cross-section or with extension joints that do not comply with the regulations in force.
  • The use of domestic sockets and plugs is prohibited.

Hydraulic supply connection

  • The appliance must be connected to the water mains via a hose. There must be a shut-off valve between the water mains and the appliance’s valve. The shut-off valve must be located close to the appliance and in an easily accessible position.
  • The water supply, temperature and pressure must be compatible with the machine’s technical specifications.
  • If the water hardness is greater than 14 F (8 dH), we recommend using the machine with an external water softener installed before the valve.
  • In the case of very high concentrations of mineral residues in the water, we recommend the installation of a demineralisation system.

Connection to the drain line

  • The drain line must consist of a free sump, with adequate dimensions for the capacity of the drain hose supplied with the machine and equipped with a siphon. The pipe must be able to reach the sump, without being pulled, constricted, bent, squeezed or forced by anything.
  • The sump is emptied by gravity, so the drain must be at a level below the base of the machine.
  • If the drain is not at a level below the base of the machine, it is possible to use the version with a drain pump (available on request). In this case, the maximum height of the drain is 90 cm.
  • Always check that the drain is working properly and that it is not clogged.
  • Any other solution must be agreed in advance and approved by the manufacturer.

Rinse aid and detergent

  • Dosing of the rinse aid and detergent is done via the dosing unit installed on the machine, if provided by the model.
  • Calibration of the dispensers must be carried out by the installation technician according to the hardness of the water itself.
  • NEVER use chlorine- or hypochlorite-based detergents.
peristaltic dosing pums sistema
  • The liquid level in the container must be adequate for suction; it must never be allowed to drop to empty or be topped up with corrosive or impure products.
  • Before proceeding with calibration, fill the feed pipes of the dosing units with the relevant product. Both operations must be carried out from the control panel.
  • The installation of an automatic peristaltic detergent pump is always recommended.

Cleaning and maintenance of the dishwasher

Cleaning the dishwasher tank

Many industrial dishwashers have a self-cleaning cycle at the end of the working day, but this is only effective if the correct amount of detergent is used, to prevent scale formation from detergent build-up.

Overly aggressive or abrasive sodium hypochlorite-based cleaning products such as bleach must be avoided at all costs.

Grease and limescale in the tank can be cleaned with specific products; it is a good idea to use a descaling agent according to the instructions in the related technical data sheet, carrying out a maximum of 4 empty washes.

vasca a L della lavastoviglie Unica

Cleaning the front panel and control display

It is important to clean the front panel of the industrial dishwasher often with a damp sponge: the impurities are very difficult to remove after a long time and can even discolour the surfaces.

pulizia display lavastoviglie professionale

The control panel must therefore be cleaned regularly with a damp cloth and then dried with a soft cloth.

Cleaning the filter unit

pulizia filtro lavastoviglie
  • Carefully remove all dishwasher filters. Cleaning the washing tank filters: after extracting the filter from its housing, remove particles and dirt residue. Then rinse with running water. Replace the filter in its housing, taking care to install it correctly. Never operate the dishwasher without the filters. If a degreasing agent is used to clean the filters, rinse very well to avoid foaming once the filters are reinserted in the machine. 
  • Carefully re-position each part after completing the listed operations.

Cleaning the dishwasher washing arms

It is essential to switch off the dishwasher in order to be able to dismantle the washing arms safely. After removing the lower basket, use a pointed object such as a small screwdriver, toothpick, or toothbrush to clean the nozzles from which wash and rinse water flows. Once finished, rinse. The Sistema Project Italia dishwashers’ snap fit nozzles can be easily removed for convenient and thorough maintenance.

For deeper cleaning, the wash and rinse arms, also known as spray arms, are easily removable to allow periodic cleaning of the nozzles and prevent possible obstructions and/or deposits. Simply unscrew the nut that fastens them to the pivot and the arms can be removed for more comfortable cleaning.

Cleaning the washing-rinsing unit:

  • Unscrew the nut and pull out the arms
  • Wash each part under running water, clean the nozzles carefully using a toothpick or small pointed tools if necessary, the nozzles can be disassembled for better cleaning or be replaced.
  • Clean the pivot pins of the arms inside the machine and the arm support assembly
  • Re-position the arms and check that they rotate freely
wasking the water jet holes of the washing arm

Non-routine dishwasher maintenance

Approximately every 1500 washing cycles, it is a good idea to check the general condition of the dishwasher more thoroughly by carrying out extraordinary maintenance with the support of a technician. This is to prevent more complex and serious machine problems and faults from occurring. It is therefore important to:

  • change the detergent and rinse aid suction and dosing tubes
  • check whether limescale has formed in the boiler using a vacuum cleaner to extract the limescale
  • check for limescale build-up on the heating element. If it is present, use a degreasing product
  • check that the safety micro switch is working properly
  • clean the solenoid valve filter
  • clean the steel surfaces of the dishwasher with specific products for steel

Dishwasher unused for a long time. What to do?

If the industrial dishwasher has not been used for a long time, it is advisable to carry out the following checks and operations with the help of a technician:

  • changing the draining and dosing pipes
  • check the washing and rinsing hydraulic circuit
  • check that the washing, rinsing and drainage pumps rotate and work properly
  • perform at least one vacuum cycle to check that there are no leaks and that all components are working (pressure switch, solenoid valve, heating elements, etc.)

Sistema Project Italia‘s commercial dishwashers for bars and restaurants are made of AISI 304 – 18/10 stainless steel, which is easy to clean both internally and externally, and unalterable over time.

However, it is necessary to follow a few but fundamental rules summarized below:

1) Connect the industrial dishwasher to a general circuit breaker or fuses, and install an efficient earthing connection in order to prevent potential leakage currents;

2) Connecting the machine to a centralized water treatment plant, prevents limescale build-up;

3) Check that the water hardness is within ‘reasonable limits’ ;

4) Use quality detergents and rinse aid. To also protect the environment, we recommend not using corrosive and/or polluting products and not exceeding the doses recommended by the manufacturers;

5) Change the water in the tank at least 3 times a day or whenever necessary, if you do not have a fresh water dishwasher installed;

6) Regularly check the level of detergent and rinse aid in the tanks and replace them if necessary;

7) Daily cleaning of the filters is highly recommended; remove and clean the first tank filter and the pump suction filter;

8) Do not allow dirt of any kind to enter the pipes; this would lead to clogging of the washing or rinsing nozzles and thus to inefficiency of the dishwasher;

Points 1-2-3-4, if not correctly implemented, can give rise to corrosive phenomena which can be seen in the form of MICRO-POINTS visible to the naked eye. This can represent the start of the corrosive and unaesthetic process.

The other points described can lead to functional defects.

Not enough for you?

Contact our service department for further advice. If service is needed in your area, we will be able to direct you to a suitable technician.

Sistema Project Italia staff