7
2.3 - Operating limits
•
Cooling mode:
Supply air temperature 12°C, when the unit is installed in
an ambient temperature of 27°C dry bulb and 65% relative
humidity.
•
Heating mode:
The air discharge temperature must not exceed 60°C to
avoid damage of the discharge spigots.
To avoid the risk of stratification and the resulting discom-
fort, Carrier advises to keep the discharge temperature
below 35°C.
•
Operating environment
The 42EM Atmosphera has been designed for internal
application in “urban” conditions having a non-corrosive,
dust free and non-marine environment.
•
The concentrations of the following chemicals must not
be exceeded in any event:
•
SO
2
< 0,02 ppm
•
H
2
S
< 0.02 ppm
•
NO, NO
2
< 1 ppm
•
NH
3
< 6 ppm
•
N
2
O
< 0.25 ppm
Recommended coil water quality
At installation handover, and then periodically every year, it is
advised to analyse the water for bacteria (detection of ferro-
bacterias, H
2
S producing and sulphate reducing bacteria) and
chemicals (in order to avoid problems due to corrosion and
scaling).
The water circuit must include all the necessary elements for
the treatment of the water: filters, additives, intermediate
exchangers, purges, drains, isolating valves, etc., according to
the analysis results.
The results must be in accordance with the values shown below:
•
Total hardness in French degrees:
10 < TH < 15
•
Chloride [CL
-
]
< 10 mg/l
•
Sulphate [SO
4
2-
]
< 30 mg/l
•
Nitrate [NO
3
-
]
= 0 mg/l
•
Dissolved iron
< 0.5 mg/l
•
Dissolved oxygen
4 < [O
2
] < 9 mg/l
•
Carbon dioxide [CO
2
]
< 30 mg/l
•
Resistivity
2000<Resistivity
<5000
Ω
cm
•
pH
6.9 < pH < 8