TECHNICAL MANUAL
Chapter 5 - Technical features
NGSi 05÷15
7
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The data in this manual are not binding and they can be modified by the manufacturer without notice. Reproduction of this manual is strictly prohibited
CHAPTER 5
TECHNICAL FEATURES
NGSi series water chillers and heat pumps are designed for residential and commercial applications. They are extremely versatile and when
operating in heat pump mode they are able to produce hot water at a temperature of 55°C for environmental heating and domestic use. The
brushless INVERTER compressor, combined with an electronic expansion valve, pump and variable speed fan, optimises the power
consumption and operating efficiency of the refrigerating components.
5.1 Frame
All NGSi units are in hot-galvanised sheet metal, painted with polyurethane powder enamels baked at 180°C to ensure the best resistance to
atmospheric agents. The frame is free-standing with removable panels for easier inspection and maintenance of the internal components. All
screws and rivets for outdoor installations are in galvanised steel.
5.2 Refrigerant circuit
The refrigerant circuit has been manufactured with components supplied by top international producers and in accordance with the UNI EN
13134 standard on braze-welding procedures. The refrigerant gas used is R410A. The refrigerant circuit includes: 4-way reverse cycle valve,
electronic expansion valve, liquid separator (07, 10 and 15 models), liquid receiver, inspection valves for maintenance and checks, PED
standard safety device (high pressure pressure switch), pressure transducers for accurate control of evaporating and condensing pressures and
filters to prevent fouling of the thermal expansion valve.
5.3 Compressors
The DC inverter compressors are of rotary hermetic (05 and 07 models), twin rotary (10 model) and scroll (15 model) types, specifically
designed for use with R410A refrigerant; they are all equipped with thermal overload protection and mounted on rubber dampers.
The compressors are installed in a separate chamber, out of the air stream, to reduce noise.
The crankcase heater is powered up when the compressor is off by at least 30 minutes and if the discharge temperature is below 20°C (with
hysteresis of 2.0°C). The crankcase heater is disabled when the compressor restarts. It is recommend to plug the unit in and put it on stand-
by at least 6 hours before it starts operation.
Compressors can be inspected through the front panel, which allows maintenance to be performed even with the unit in operation.
5.4 Air side exchanger
The air side heat exchangers are constructed with copper tubes and aluminium fins. The copper tubes have a diameter of 7 mm in the 05 and
07 models and 5/16” in the 10 and 15 models; the aluminium fins are 0.1 mm thick. The tubes are mechanically expanded into the aluminium
fins to improve the heat exchange factor. The geometry of these exchangers guarantees low air side pressure drop, meaning that fans
operating at low rpm can be used (reducing the unit’s noise level).
5.5 Fans
The unit is fitted with plastic axial fans with aerofoil blades. They are all statically and dynamically balanced and supplied complete with
safety grille as required by the EN 60335 standard (safety of household and similar electrical appliances). The fans are installed on the unit
on rubber dampers to reduce the noise level. All electric motors used are of 8 pole modulating brushless type (200/1000 rpm). The motors are
directly coupled and equipped with integral thermal overload protection. Motors all have IP X4 protection rating.
5.6 User heat exchangers
The user heat exchangers are of braze-welded plate type and are in AISI 316 stainless steel, insulated with closed-cell material in the factory;
they can be equipped with antifreeze heaters (AK optional accessory). Each evaporator is protected by an antifreeze protection temperature
probe, which starts up the water circulator, even with the unit switched off, if the conditions set on the control unit occur.
PHYSICAL AND CHEMICAL PROPERTIES
Colour: Colourless.
Odour: Slight.
Boiling point: -52.8°C at atmospheric pressure.
Flash point: Non-flammable.
Relative density: 1.08 kg/l at 25°C.
Solubility in water: Negligible.
STABILITY AND REACTIVITY
Stability: No reactivity if used in compliance with the relative instructions.
Materials to avoid: Strong oxidants. Incompatible with magnesium, zinc, sodium, potassium and aluminium.
The incompatibility becomes more serious if the metal is in powder form or if the surfaces have recently
not been protected.
Hazardous decomposition
products:
These products are halogen compounds, hydrofluoric acid, carbon oxides (CO, CO2) and carbonyl
halides.
TOXICOLOGICAL INFORMATION
Acute toxicity: (R32) LC50/inhalation/4 hours/lab.rats >760 mg/l
(R125) LC50/inhalation/4 hours/lab.rats >3480 mg/l
Local effects: Concentrations significantly above the TLV can cause narcotic effects.
Inhalation of products in decomposition can lead to respiratory difficulty (pulmonary oedema).
Long-term toxicity: No carcinogenic, teratogenic, or mutagenic effects observed in laboratory animals.
ECOLOGICAL INFORMATION
Global warming potential GWP
(R11=1):
1.730
Ozone depletion potential ODP
(R11=1):
0
Considerations on disposal: usable with reconditioning.
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