10
AHU Kit – Installation Instructions –
11/2021
General information and safety notes
1
WARNING
The following precautions need to be followed strictly, in order to avoid hazardous situations, which
could result in death or serious injury.
A fire or explosion hazard and the generation of poisonous gas may result if R32 refrigerant
gas comes into contact with open flames.
► The air conditioning appliance with direct expansion (DX) coil shall be installed, operated
and stored in a space without continuously operating ignition sources (e.g. open flames,
an operating gas appliance or an operating electric heater).
►
If DX coil appliance is not installed in a separate refrigeration machinery room as
specified in EN378, calculate the maximum allowed density limit of the relevant
installation space as detailed below (see
→
1.3.1 Calculating the density limit, p. 10
).
► The DX coil appliance shall be installed, operated and stored in a well ventilated space
with a ceiling height of at least 2.5 m and a floor area larger than [A
min
] m² so that it
complies with the required density limit (see
→
1.3.1 Calculating the density limit,
► Pay particular attention to prevent refrigerant leakages during installation, maintenance
and repair work (see
→
1.3.2 Preventing leakages, p. 18
► If a leak is suspected, do the following:
>
remove or extinguish all naked flames immediately
>
ventilate the room immediately
● use a calibrated electronic leak dectector to detect any leaks
(see
→
)
► Repair any leaks diligently (see
→
refrigerant system with refrigerant and checking for any leaks again.
ATTENTION
For full details on the required precautions for the installation and maintenance of an R32 unit,
always refer to the Installation Guide of the relevant PACi or PACi NX unit.
1.3.1 Calculating the density limit
As R32 is a slightly flammable refrigerant (ASHRAE flammability class A2L), the requirements for
the installation space of the DX coil appliance must comply with the applicable regulations and
standards, such as IEC60335-2-40 and EN378.
Depending on perspective, the density limit determines either the minimum floor area “A
min
”
(specified in square metres (m²)) required for a given refrigerant charge amount (specified in
kilogrammes (kg)), or vice versa the allowed maximum refrigerant charge “m
max
” for the DX coil
appliance (specified in kilogrammes (kg)) in relation to the floor area of the available installation
space (specified in square metres (m²)). The charge limits for R32 installations (based on
IEC60335-2-40, 6th edition) also depend on the mounting position of the DX coil.
!
02.06.2021, JW
Better replace “EN60335-2-40” with “IEC 60335-2-40,
6th ed.”, as the EN has not yet followed the latest
IEC, but will follow within the next year.
22.07.2021, cH: done
Summary of Contents for PAW-280PAH3M-1
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