Pfannenberg DTS Air Conditioner - Manual (Page 4)

Operating and Installation Instructions DTS Air Conditioner
08.2001 085 408 022 4
4 Application and Function
The Air Conditioner is designed to abduct heat from sealed switch cabinets. Any
other use shall be deemed as a deviation from the design use.
The units operate according to the principles of a heat pump with two airflow circuits
mutually isolated by mechanical means. The "internal airflow circuit" draws off heat
from the electrical and electronic components into the Air Conditioner. The thus
heated air is cooled and dehydrated inside the cooling unit and then blown back into
the switch cabinet interior.
The "external airflow circuit" makes use of the ambient air to cool the condenser and
thus expel the system's inherent heat into the atmosphere.
The fan in the "internal airflow circuit" is always in operation whenever voltage is
applied to the Air Conditioner. The thermostat in this circuit regulates the
compressor and the fan in the "external airflow circuit".
The air conditioner has been provided with an internal condensation removal system
(depending on the model, supplements). The enclosure air is drawn across the
evaporator pipes, it is cooled and dehumidified before it is blown back into the
enclosure. The condensation has been removed from the air and the ambient air
stream evaporates. The heat of the condenser pipes aids this evaporation.
Although the unit has been designed to remove the small amount of the
condensation that will develop due to air infiltration into the sealed enclosure, care
must be taken to provide the proper drainage for the overflow drain of the air
conditioner. An overflow may occur if the air conditioner is operated for a period of
time with the enclosure unsealed, allowing moisture laden ambient air to enter the
evaporator section.
If water if found to be draining continuously from the overflow drain during normal
operating, this means that a significant quantity of moisture laden outside air is
entering the enclosure. Care should be taken to seal the enclosure against such
infiltration.
CAUTION :
Any effective cooling operation can produce condenser water. Therefore, the
Air Conditioner should only be fitted to sealed enclosures and only operated
with closed doors.
We recommend that you install a contact switch on the door of the enclosure
to cut out the cooling unit whenever the enclosure door is opened.