Air-to-water heat pump
Reverse cycle air-to-water heat pump with manual mode switch. The unit is supplied with anti-freeze oil and refrigerant and has been factory tested. On-site installation therefore just involves making connections to the mains power and water supplies.

Unit charged with R407C ecological refrigerant.

STANDARD UNIT COMPOSITION
Supporting frame
Base and frame in thick hot-galvanised shaped sheet steel. All parts polyesters-painted.

Panelling
The external panelling, made from galvanized, epoxy painted sheet metal, offers maximum ease of access to the internal components. All the panels are lined with high density sound-absorbing material.

Screw compressors
Semi-hermetic screw-compressors with 2 five and six- lobe rotors. The five-lobe rotor is directly splined onto the 2-pole motor (2,950 rpm) without the use of overgears. Compression occurs five times every motor turn and therefore the gas discharges continuously without the typical throbbing of reciprocating compressors. Leading-edge numerical control machines were used to make the rotors and machine the bearing seats. The slide valve can limit the cooling capacity of each compressor by 50% and 75%. In addition to the standard no-load starting feature, the motors are fitted with electric starting devices which limit the power absorbed during the compressor starting phase. A check valve on the refrigerant delivery line prevents the rotor from reversing after stopping. Special maintenance-free bearings allow very long work cycles. Lubrication is forced, without the use of an oil pump. The high efficiency built-in oil separator ensures the constant presence of oil in the compressor. The rotors are dynamically balanced to ensure the vibrations typical of reciprocating compressors do not occur. The absence of vibrations and the absence of delicate intake and delivery valves, in addition to very fine manufacturing tolerances, sophisticated quality controls during the production process and a limited number of moving parts, guarantee quiet and highly reliable operation. Each compressor is fitted with manual-reset motor thermal protection, delivery gas temperature control, an oil level float, an oil level sight-glass and an electric resistance for heating the oil when the compressor is stopped.

Water-refrigerant heat exchanger
Direct expansion heat exchanger type with asymmetric refrigerant paths to maintain the correct refrigerant velocity inside the tubes during both liquid and gaseous phases. The steel shell is insulated with a closed-cell anti-condensation lining. The copper pipes are internally grooved so as to improve the heat exchange. The pipes are mechanically expanded onto the tube plate ends. An antifreeze electric heater prevents the formation of ice inside the casing of the exchanger when the unit is not operating but connected to the electrical supply. Differential pressure switch for controlling the water flow is fitted standard.

Refrigerant-air heat exchanger
Aluminium fins and copper tubes type heat exchanger. The aluminium fins are correctly spaced to guarantee the best heat exchange efficiency. The lower part of the exchanger functions as a sub-cooling circuit thus increasing the cooling capacity.

Fans
Axial electric fans, protected to IP 54, with external rotor and profiled die-cast aluminium blades. Housed in aerodynamic hoods complete with safety grille. 6-pole electric motor with built-in thermal protection. Pressure switch condensing control by sequentially excluding certain fans.

Refrigerant circuit
Main components of the refrigerant circuit:
- compressor discharge check valve,
- compressor discharge shut-off valve,
- compressor suction shut-off valve,
- liquid line shut-off valve,
- liquid line solenoid valve,
- dryer filter with replaceable cartridge,
- refrigerant line sight glass with humidity indicator,
- externally equalised thermostatic valve,
- high pressure safety valve,
- low pressure safety valve (if required by regulations),
- high and low pressure switches,
- high and low pressure gauges,
- liquid receiver and separator,
- 4-way reverse cycle valve.

Electric power and control panel
Electric power and control panel, built to EN 60204-1/EC 204-1 standards, complete with:
- control circuit transformer,
- general door lock isolator,
- power circuit with bar distribution system,
- fuses and contactors for compressors and fans,
- terminals for cumulative alarm block (BCA),
- remote ON/OFF terminals,
- spring-type control circuit terminal board,
- electric panel with double door and seals for outdoor installation,
- electronic controller.

Basic model
Unit without heat recovery.

Model with partial heat recovery (D)
Reverse cycle air-water heat pump fitted with a desuperheater. Similarly to the basic unit, this version produces hot or chilled water in the primary circuit, depending on which seasonal mode has been selected. Compared with the basic configuration, this version features a water/freon heat exchanger on the gas delivery line. This heat exchanger, fitted in series with the traditional cooling circuit condenser, is large enough to recover just desuperheating heat for the production of medium-to-high temperature water (secondary or recovery circuit). Hot water can be produced in the recovery circuit for domestic hot water and the like both in summer and winter. The heating capacity of this circuit is approximately equal to the power input of the compressor. After going through this exchanger, the refrigerant gas enters the condenser (refrigerant-air exchanger in summer and refrigerant-water exchanger in winter) where condensation is completed. There are two operating cycles:

WINTER MODE
The exchanger to which the main water circuit is connected works as a condenser (the refrigerant-air exchanger works like an evaporator). The refrigerant-water exchanger for partial heat recovery (desuperheater) allows hot water to be produced in a second hydraulic circuit for domestic hot water and the like.

SUMMER MODE
The exchanger to which the main water circuit is connected works as an evaporator (the refrigerant-air exchanger works like a condenser). The refrigerant-water exchanger for partial heat recovery (desuperheater) allows hot water to be produced in the same way as the winter mode.

Model with total heat recovery (R)
Air cooled chiller with total heat recovery. Compared with the basic configuration, this version features an additional refrigerant/water heat exchanger on the gas delivery line. This heat exchanger, fitted in parallel with the traditional cooling circuit condenser, is large enough to recover heat for the production of domestic hot water and the like. The heating capacity of the heat recovery circuit is approximately equal to the cooling power plus the power input of the compressors.

AVAILABLE VERSIONS
B (base)
Standard unit.

HL (High Temperature - Low Noise)
High efficiency low-noise version.

HT (High Temperature)
Version suitable for operation with high condenser input air temperatures. This version features an oversized condensing section in order to ensure that heat is correctly exchanged even in particularly tough environmental conditions. As a result, when working at normal air temperatures, an increase in cooling capacity and a decrease in power input is obtained, thereby improving the cooling efficiency ratio (E.E.R.).

LN (Low Noise)
Low noise version. This configuration features special soundproofing for the compressor chamber and reduced fan speed. Fan speed is automatically increased if environmental conditions are particularly tough.

SL (Super Low Noise)
Super low noise version. This configuration features special soundproofing for the compressor chamber, reduced fan speed, an oversized condensing section, spring supports for the compressors, vibration proof joints on the compressor intake and delivery lines, and a muffler on the compressor delivery line. Fan speed is automatically increased if environmental conditions are particularly tough.