Installation

The units could be installed by using motorized or manual forklift. After installation it is highly important to remove all packaging and to dispose it properly. Special attention must be paid in order to prevent children to get in contact with packaging. That contact may pose potential health hazard.

The unit must be always positioned horizontally. If the floor is not completely horizontal, antivibration pads must be used to insure that the unit stands horizontally. Antivibration height adaptive pads for unit leveling are provided by Frigo Plus Ltd. To ensure horizontal position of the unit use spirit level and it is recommendable to use the lower parts of the machine as a reference points. After testing is completed, unit must be securely attached to the floor.

Technician must use spirit level to check unit position - it has to be mounted horizontally.

If the device is placed in the technical area (e.g. engine room), the space must be adequately ventilated in order to avoid high concentrations of refrigerant in the air. Vents must be designed according to the applicable standards.

Electrical cabineta

The circuit is designed for power supply of 380-400V/3+N phase/50Hz.

Strujni krug treba biti napajan kablom koji je prikladan za snagu grupe i prema uvjetima na mjestu ugradnje.

On the label on the unit, among other things, nominal electrical power (kW) and maximum power current (A) must be written. Nominal absorbed power (kW) is outlined in the tables in the chapter "Description / Technical data" of this manual. Electrical technicians must connect electrical cabinet and ground the unit strictly following all Croatian regulations as well as specific regulations of local area in which the unit is installed.

When carrying out power cable, the gland should be tightened to insure waterproof characteristics. All connections and wires must be properly insulated.

The unit must be grounded (yellow – green cable).

The unit must be grounded.

If installation requires differential protective device (GFCI), it must be connected to power cord and designed for usage with electrical motors. Calibration should be no less than 3% of the sum of the nominal current of the compressors.

Frigo Plus d.o.o. is not liable for all the power outages caused by improper calibration and the accident occurred due to a lack of coordination between the calibration of differential protective switches (GFCI’s) and power supply.

For more information on electric components see chapter "Technical characteristics of the circuit (wiring diagram)" of manual. It is necessary to check the circuit wires and connecting terminals after transport.

Refrigerant circuit

The unit includes:

• Uređaj se dostavlja sa:
• Refrigerant circuit filled with nitrogen › all the pipes (including pressure side pipe) are closed with shut-off ball valves (for more information see operating diagrams of the refrigerant circuit).

Building units operating with refrigerant R404A demands meeting specific standards: all welds must be made in a stream of nitrogen to avoid residual stresses that may damage the device.

Pressure test

Open all valves and components of the unit. Fill and pressurize the unit with a mixture of nitrogen and refrigerant. (First, fill a small amount of refrigerant, then supplement with nitrogen until a pressure of 20 bars). Refrigerant is used to find possible micro-leaks which will be detected by using electronic leak detector. In case of pressure drop it is necessary to find leak locations on the unit (special attention must be paid to the junctions). In a case of leakage, leak location must be isolated and patched before the system is pressurized again. The system must be pressurized for minimum of 12 hours. If within that period the pressure does not vary to a great extent we can conclude that the system is secure and doesn’t leak.

Preparation of filters

The device is provided with a filter without the cartridges. The cartridges are supplied in hermetically sealed containers. Before the first use, in the suction filters appropriate cartridges must be placed. Cartridges are placed in the filter housing using the packet provided parts (interior mesh sieve, cover and spring). Installation is performed according to the instructions given in the box filter.

The system should be closed, and connected to a vacuum pump. Entire system or just certain parts of the system, depending on specific system type, must be vacuumed to a pressure of 0.015 bars. After doing so, the system must be filled with refrigerant (using pressure gauge connections on liquid and suction line) to a pressure of 0.15 bars, and checked whether there are any leaks within the system. The system is then left to rest for a minimum of 12 hours, and if during that period no significant change in pressure is noticed, next stage of testing can commence.

Control of pressure switches, charging system and commissioning

The unit is delivered with a double safety pressure switches (high and low pressure) for which there are a corresponding tag with indicated shut off pressure and serial number. Switches are calibrated to the factory settings onto the pressure indicated in the table in chapter "Technical characteristics of the circuit (wiring diagram)" of manual. After calibration, the regulation screw must be blocked to avoid undesired and unauthorized changing. Reset of pressure switch must be done manually for high pressure and automatically for low pressure.

Always check whether the seals are intact. Any movements that can cause rotation of regulation screw must be avoided at all times.

All malfunctions and irregularities of the unit must be resolved before the safety pressure switch is reset.

If the unit is equipped with pressure switches for manual operation (in case of failure of automatics) of the compressor or condenser fan, it is necessary to check out their factory calibrations. Operation of motor protection switches should be set to the values given in the table (see the end of this chapter).

Microprocessor control for automatic operation of the compressor can be programmed during development of the unit to the standard working conditions.

Before connecting unit to electrical grid, power switch has to be set to postion “0”. Use voltmeter to check voltage: voltage value that supplies the device must be 400V with a maximum variation of 10%.

Check the phase difference. Differences between the phases should not exceed 3%.

First charging of the unit must be done with liquid refrigerant into a liquid receiver using tanks with two separated valves for gaseous and liquid phase, or simply turning the tank upside down if there are only normal valves. This procedure is conducted to insure that the concentration of components of the refrigerant does not vary.

Prior starting the unit crankcase heaters must be turned on for at least 6 – 8 hours. In order to do this action without starting the compressor the motor protection switches 1QM1, 1QM2 and 1QM3 must be turned off. Check the electrical resistance between terminals 14 – N, 24 – N or 34 – N. Turn the power switch to “ON”.

After the desired period has passed, turn the power switch onto “0” and re-enable previously turned off motor protection switches. Make sure that both, intake valve and suction valves are open. If so, the unit can be safely put into operation.

If electrical cabinet requires repairing under voltage, it must be executed only by qualified personnel. Red security lights should be installed to indicate that electrical cabinet door is open. While repairing the machine, technician cannot leave the unit unattended.

Check whether the position of the condenser fan is correct, and if necessary, start with the calibration of high pressure switch.

After the start, the refrigerant should be replenished into the intake manifold in the manner previously described. The system should be filled gradually and the action should be stopped when the refrigerant level is stabilized. The refrigerant level is stabilized when indicator on lower glass reaches top position.

Oil level in compressors

During commissioning and trial run it is CRUICIAL to check oil level in compressors. Compressors used in these units do not have an oil pump, therefore are not equipped with oil differential pressure switch to protect them against insufficient amount of lubricating oil. Lack of lubricating oil in the compressor can cause serious damage.

The unit must not be left unattended during first 48 hours of trial run.

Passive oil recovery system

During normal operation of the compressor, a part of the oil leaves the compressor with the refrigerant into the discharge pipe and the condenser and further into the other parts of installation. The entire cooling system MUST adequately designed primarily to satisfy all the working conditions (fluid velocity, pressure drops, etc.) and to ensure a smooth and continuous return of oil into the intake manifold. Optimized intake manifold implies its proper design. To ensure equal return of oil to the compressors the manifoldmanifold must be positioned horizontally . manifold must be positioned horizontally

Prior to its delivery oil collector is filled with the initial amount of oil (up to mid-level on the sight glass of the intake manifold).

During the first 48 hours it is necessary to constantly control the oil level because some amount of oil can remain in the installation (siphons, evaporators, piping and other components). The amount of oil that could remain in the installation depends on its type and size.

If during this period the amount of oil in the compressors falls below 1/4 sight glass, the unit must be stopped immediately and adequate amount of oil should be replenished into the intake manifold. .

It is necessary to ensure that the oil level in the compressors stays above 3/4 of sight glass.

This method of oil recovery can cause an uneven level of oil in certain compressors but it is compulsory to ensure that the oil level never drops below 1/4 of sight glass.

Active oil recovery system

It is necessary to check oil level in the receiver as well as in each compressor (checks are carried out while the compressors are turned off). At all times oil level on the level controller must be at 3/8 of sight glass, while in the receiver it must be at the top of its sight glass. If not, the system should be filled with oil until the upper values are reached. After 48 hours of work, if the system operates correctly, the oil level in the oil receiver should not be below 1/2 of lower level of sight glass. Oil should be replenished only if its level drops below the 1/2 of the lower level of the sight glass.

After an initial period of operation (approximately 12 hours), or when on the suction filters a significant increase in oil loss is observed, the unit should be stopped. After the unit is stopped, filters should be dismantled and the cartridges should be replaced, using cartriges for mechanical filtration. Vacuum any opened parts of the system, and let the unit into operation. Oil level should be checked again both in compressors and receiver. Oil level should never drop below the bottom sight glass.

If the oil receiver is changed while unit is already in operation, the oil must be added very carefully. Recovery of oil, which is distributed in the pipeline, must be obtained within one day of work. If the oil level does not reach the upper sight glass, sufficient amount of oil should be added. Otherwise, if the oil level exceeds the upper sight glass, it is necessary to drain the excess oil. This action can be executed through a valve mounted at the bottom of the receiver.