7 - MAINTENANCE AND OPERATING
INSTRUCTIONS
7.1 - General
The AHU(s) require little maintenance. The smooth
inside and outside finish of the panels makes
maintenance very simple.
For dry sections: once a year thoroughly check the
inside and outside of the AHU casing. For
maintenance of wet sections (coolers and humidifiers)
please refer to the air handling section concerned.
7.2 – Casing Panels
7.2.1 - Inside Installation
a) Internal inspection of the casing of double-skin
panels and of all dry parts.
Remove contamination with water and a mild
household soap solution. Where damage of the paint
finish has occurred, if necessary remove rust and
touch up with good quality anti-corrosive primer and
paint. The outside air intake sections can show signs
of corrosion as they contain wet parts and are affected
by mist, rain and air pollutants.
b) Outside inspection of the coating.
If damage to the paint treatment has occurred, remove
the rust (if necessary), and touch up with good quality
anticorrosive primer and paint.
7.2.2 - Outside Installation
Check the sealed joints of AHUs installed outside and
if required seal again with a UV-resistant and paintable
kit. Treat damage as for inside installation.
7.3 - Doors and Access Covers
Check locks and hinges of all doors and access
covers. For outside installation check the storm cord.
7.4 - Flexible Connections
Check the flexible connections for damage.
7.5 - Earthing
Ensure that the unit is earthed and installed in the
correct manner.
7.6 - Dampers
Remove excess contamination by cleaning it with
compressed air. Check adjusting bolts and linkage and
if necessary tighten. Ensure that the damper blades
run free of the casing.
7.7 - Outside Air Intake
Especially the outside air intake is contaminated by
pollution taken in with the air. The maintenance interval
must be observed, as irreparable damage of the
panels might otherwise occur. Clean the outside air
intake well and repair damage as described in point
7.2.1.
7.8 - Filters
The filters must be inspected once a month for excess
pollution, pressure loss, damage and seating of the
slide-in filters or built-in frames. With slide-in filters
ensure that the filters have been correctly positioned
and have been pushed well against each other from
below. When replacing built-in filters you must ensure
that the filter has been pushed well against the sealant
and that the clips have been correctly installed. Filters
must be replaced at the required intervals. The timing
of the replacement depends on the type of filter, quality
and the degree of contamination of the air. The
pressure loss across the contaminated filter can be
measured with a pressure differential gauge.
Maintenance instructions of special filters are available
on request.
7.9 - Electric Heaters
Check once a year for contamination, and if necessary
clean with compressed air. Check the connections in
the control box. Check the operation of the thermostat.
The following warning label is located on the panel:
electrical voltage and hot surface.
7.10 – Cooling Coil
Check once a year for contamination and if necessary
clean with compressed air against the direction of the
air flow or clean with a vacuum cleaner. Check for
leakage. Check the fins of the droplet eliminator after
the coil. Clean the siphon and check its operation.
Check the condensate pan for contamination and
clean if necessary.
7.11 - Heat Recovery Wheel
Check the rotor once a year for contamination, and if
necessary clean with compressed air. Check the rotor
speed and compare it with the design data.
Check the rotation of the rotor. Depending on the rotor
material the wheel can absorb moisture. When
stationary the wheel will become moist on one side
and thus heavier. The rotor speed can be set to
intermittent in the controller so that the wheel will rotate
“x” times per time unit.
13
