Technical Features

Frame

All QLAC unit enclosures are manufactured from hot-galvanised sheet steel, painted with polyurethane powder enamel and stoved at 180°C to provide a durable, corrosion resistant finish. The frame is self- supporting with removable panels. All screws and rivets are made from stainless steel. The paint colour is RAL 7035.

Refrigerant circuit

Refrigerant is R407C. The refrigerant circuit is assembled using quality brand components and in accordance with ISO 97/23 concerning welding procedures. Model sizes 140 and upwards have multiple refrigerant circuits. Each refrigerant circuit is totally independent of the other. Failure of one circuit does not influence the other circuit. The refrigerant circuit includes:

Liquid line manual shut-off valve Sight glass

Filter drier

Thermal expansion valve with external equalizer

Electronic expansion valve with control to optimise efficiency in part load conditions (option) Reversing valve (heat pump version only)

Non return valve (for heat pump version only) Liquid receiver (for heat pump version only) Schraeder valves for maintenance and control Pressure safety device (according to PED requirements)

Compressors

Scroll compressors are used, each fitted with a crankcase heater and provided with thermal overload protection via a klixon embedded in the motor winding. Compressors are mounted in a separate chamber in order to be separated from the air stream and to enable maintenance to be performed whilst the unit is still operating. The crankcase heater is always powered when the compressors are in stand-by. All compressors are in tandem configuration. This creates higher efficiencies uring part load conditions compared to units with independant refrigeration circuits per compressor.

Condensers

Condensers are made of copper tubes and aluminium fins. The diameter of the copper tubes is 3/8” and the thickness of the aluminium fins is 0.1 mm. Tubes are mechanically expanded into the aluminium fins to maximise heat transfer. The geometry of these condensers guarantees a low air side pressure drop and allows the use of slow running (and low noise) fans. The condensers can be protected by a metallic filter (option).

Fans

Fans are axial type with aerofoil blades. They are statically and dynamically balanced and supplied complete with safety fan guard that complies with the requirements of EN 294. They are mounted on the unit frame using rubber anti-vibration mounts. The electric motors are 6 pole (approx. 900 rpm) in the low noise version and 8 pole (approx. 750 rpm) in the extra low noise version. The fans are directly driven and are fitted with integral overload protection. Motors have moisture protection to IP 54.

4	06617645-02