Stulz Tel-Air-2 Series, Operating Instructions Manual

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E/0618/35A/20
3.3 Mechanical parts
Structure
These machines are built using self-supporting panels made of painted galvanised sheet metal to
guarantee good corrosion resistance (not suitable for corrosive and saline environments). They
make the machine easy to inspect and, at the same time, offer adequate protection to its internal
components. The external panels are internally lined with a 3 mm layer of sound-absorbing
material.
The internal components of the unit can be accessed by simply removing the cladding panels.
This is done by undoing their fastening screws.
Air filter
Belonging to class G4, it is designed to prevent large dirt particles present in the environment
from obstructing airflow through the evaporator.
Drip-tray
Made of sheet aluminium, it is located under the evaporator coil to collect the moisture from the
internal air which condenses on the surface of the coil during cooling. It is fitted with a union for
external drainage.
Damper
This damper, fitted in units featuring the free-cooling option, consists of a metal baffle powered
by a servomotor for directing inside and outside air flows. The damper body is made of
galvanised sheet metal.
3.4 Cooling components
The unit comprises a hermetic cooling circuit consisting of a compressor, condenser, refrigerant
filter, thermostatic valve and evaporator. The air inside the shelter is cooled without coming into
contact with the external air in cooling mode.
The system works as follows:
The compressor compresses the refrigerant gas bringing it to a high pressure and temperature.
The hot gas, by going through the condenser, is cooled and liquefied thus releasing heat to the
air in the environment. Pushed through the thermal expansion valve, the liquid refrigerant loses
pressure, which makes it prone to evaporation. This takes place in the evaporator, where the
refrigerant absorbs the heat of the warm air from the shelter, which is therefore cooled.
The circuit components are connected together by copper piping, appropriately welded to ensure
a greater seal. Schrader service valves are fitted internally on the compressor intake and return
lines.
Refrigerant
The refrigerant that is used is R407C (HFC). Optional: R134a.