Rivacold STH009 Manual De Uso Y Mantenimiento página 48

UK
The pipes must be fixed to the wall at all corners, welds, or every 1.5-2 meters along straight sections.
Suction Line Insulation
With an evaporation temperature below -10 °C the suction lines must be insulated with an anti-condensation pipe at least 13 mm
thick, to limit overheating.
Oil Return
All systems must be designed to guarantee oil return to the compressor. In the situation shown in Figura 5, with the condensing
unit located above the evaporator, it is important to provide siphons on the suction line every 2 m in height difference to ensure
oil return to the compressor. However in the case of horizontal sections, it is important that the suction line has a slope of at least
3% towards the compressor.
Oil Adding
In most cases for systems where the pipes do not exceed 10 meters, it is not necessary to add oil. If the pipes are over-sized
compared to normal or higher than 10 feet, a small amount of oil needs to be added.
Vacuum
Crucial for correct functioning of the refrigeration system and long life of the compressor, correct vacuum must be run into the
system, ensuring the content of air, and especially humidity, are below the values permitted. The introduction of the new gases
requires the use of new polyester oils having higher hygroscopic characteristics that require more attention when running the
vacuum; so it is recommended to run the vacuum on both sides of the circuit. In any case, the target to be achieved is to obtain a
pressure not exceeding 5 Pa.
ATTENTION:
ATTENTION:
Refrigerant Loading
After the vacuum operation, the system must be loaded with the refrigerant type indicated on the EC tag or any alternative type.
For correct loading it is recommended, after having run the vacuum, to pump part of the refrigerant into the compressor to "break
the vacuum"; then start the compressor to suck the remaining required to complete the loading process.
To ensure the correct amount of gas has been loaded, use the pressure gauges connected to the pressure intakes provided; the
pressure must comply with the correct working conditions of the machines.
ATTENTION:
DANGER:
Leakage Control
A system can only operate regularly over time, throughout the life of the compressor, if all the requirements related to the
installation are correctly carried out, also taking into account the leakage of refrigerant. It has been estimated that a refrigerant
leakage equal to that of 10% of the total system loaded, in 15 working years of the compressor, will still allow the correct
operation of the cooling system. With the new gases (R134a, R404A and mixtures) the risk of leakage through poorly carried out
welds and connections is greater due to the reduced molecular size of the gas, therefore it is essential that welds are checked for
leakage using suitable methods and equipment for the gas concerned.
Crankcase Heater (optional)
If the compressor operates at a temperature below + 5°C, it is advisable to use a crankcase heater to prevent the accumulation of
liquid at the bottom of the compressor during periods of inactivity, inevitably requiring choking of the condenser, for example by
reducing the air inlet (e.g. by the speed adjuster).
Working Cycle
The systems must be set up so as not to exceed 5 on /off cycles per hour. Activation of the Thermal/Power protection system shuts
down the compressor, and can be re-started only after the protection system has been re-set.
Picture 5 position mode condenser – evaporator
to avoid irreparable damage to the compressor do not start it in a vacuum condition and without the
gas loaded.
during the vacuum and loading stage remember to power up the solenoid valve coil of the liquid line.
the refrigerant gas mixtures must only be loaded into the system in the liquid state. The loading
operations must be carried out only by qualified staff.
For loading, recovery and refrigerant check operations, wear gloves to protect against low
temperatures.
ST-SP Pag. 48 Rev 00 02/10