The dryer and its auxiliary equipment must be connected to earth and protected against short circuits and overloads.
When the unit is powered, the voltage in the electrical circuit assumes potentially lethal values so the maximum precautions
must be adopted if work is to be carried out on the electrical circuit.
Do not open the electrical equipment enclosure panels while the electrical system is powered unless this is strictly necessary
for the execution of tests, measurements or settings.
This work must be carried out exclusively by qualified personnel equipped with suitable tools and wearing all the relevant
protective equipment to safeguard against electrical hazards.
2.2.4 Maintenance precautions
If replacement parts are needed use only original spares.
Keep a written record of all work carried out on the unit and the auxiliary equipment.
The frequency and the nature of the work required over a period can reveal adverse operating conditions which should be
corrected.
Use only refrigerant gas specified on the data plate of the unit.
Make sure that all instructions concerning operation and maintenance are strictly followed and that the complete unit, with all
accessories and safety devices, is kept in good working order.
Always keep the plant clean.
Protect components and exposed openings, plugging them, for example, with clean rags.
Precautions must be taken when carrying out welding or any repair operation which generates heat, flames or sparks.
Components in the vicinity must be protected with non-flammable material.
Do not weld or perform work that generates heat close to a system that contains oil.
Before performing any such work all systems that may contain oil must be completely drained and flushed, for example, with
steam.
Do not weld or modify a container that may be subject to pressurization.
To prevent an increase in working temperature, inspect and clean heat transfer surfaces (i.e. condenser fins) regularly.
For all dryers establish a convenient time interval for cleaning procedures.
Never use an open flame as a light source to inspect parts of the dryer.
Before dismantling parts of a plant ensure that all mobile and heavy parts are securely fixed, and ensure electrical power has
been disconnected.
When a repair has been completed make sure that no tools, detached parts or rags are left in the dryer.
All guards must be refitted after carrying out repair or maintenance work.
Do not use flammable liquids to clean components while the unit is running.
If non-flammable hydrocarbons containing chlorine are used all the relevant safety precautions must be adopted to protect
against the toxic fumes that may be given off.
Before removing any panels or dismantling any part of the unit, carry out the following operations:
•Isolate the unit from the electrical power supply by disconnecting the supply upstream of the power feeding
line.
•Lock out the disconnect switch (if present) in the “OFF” position by fitting a padlock.
•Place a sign on the handle of the disconnect switch (if present) or in its immediate proximity stating “WORK
IN PROGRESS - DO NOT CONNECT POWER”.
•Do not set the electrical power switch to ON or attempt to start the unit if the warning sign is displayed.
Coloured tracers can be used in service-maintenance operations.
Inspect all refrigerant circuit joints including connectors, flanges, and more generally all critical points (open joints) in order
to prevent possible leakage of refrigerant gas.
2.3 Refrigerant gases
The plants can be charged only with R134a.
The use and storage of cylinders containing refrigerants must be in compliance with the prescriptions of the manufacturers of
the cylinders and in compliance with the applicable safety laws and prescriptions in force in the place of installation.
2.3.1 Characteristics of R134a refrigerant
At normal temperature and pressure conditions, this is a class A1 colourless gas (classification EN 378-1).
Concentrations significantly above 1000 ppm v/v can cause narcotic effects.
In the event of leakages provide adequate ventilation of the room before entering.
