A.O. Smith AHD 290 - Manual (Page 40)

1.4 Refrigerant circuit – description
The cooling system is used for processing the heat in the inlet air. This is the
manner by which the extracted heat is transferred to the water. This process is
only possible with the external addition of energy, which takes place in the com-
pressor.
In the vaporizer, heat is absorbed from the air and refrigerant in gaseous form and
fed to the compressor. In the compressor, the refrigerant is raised up to a higher
pressure and energy level, so it can deliver the heat to the water through the con-
denser pipe, which is coiled around the tank.
The condensed coolant fluid is throttled down to a lower pressure using the expan-
sion valve so it becomes possible to repeat the cooling cycle in the vaporizer.
1.4.1 Cooling system - description
The skilled technician must make sure that all refrigerant carrying parts are emp-
tied to a level where work may be carried out without any risk to people or materi-
als, before repairs and services are carried out.
When repairing and servicing the heat pump in which the refrigerant system has to
be opened, always take extra care. If the use of an open flame is needed, (Weld-
ing, soldering etc.) special care must be taken in order to prevent fire.
1.4.2 Electrical circuit - description
When work is carried out on the heat pump, the main supply must be discon-
nected. (Pull the plug.)
When the unit is connected to the supply all local and national regulations must be
followed, along with the demands from the power supplier.
1.4.3 Water circuit - description
Only water in drinking quality may be used. During installation the choice of
material must be taken into account, and made sure those are compatible in the
entire circuit. Safety equipment must be installed to prevent over pressure in the
system.
All pipe work must comply with water safety regulations.
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