44
VTS reserves the right to implement changes without prior notice
Ventus Air Handling Units
- repeat this procedure several times at short intervals until only air goes out of the
drain hose without any visible drops of water
- screw the drain and vent plugs back
Check contamination level of heater's lamellas at least every four months. Dust deposition on the
heater surface deteriorates the heater's heating power and lead to pressure drop on the air side.
Even if the AHU is equipped with filters, with time from the air supply side, dust settles onto the
heater's lamellas. In case of contamination, cleaning should be carried out in one of the following
ways:
- with a vacuum cleaner with soft suction nozzle from the air inlet side,
- by blowing through with compressed air in a direction opposite to normal air flow direction, directing
air stream in parallel to the lamellas,
- washing with warm water with cleaning agents which do not cause aluminum or copper corrosion.
Before starting washing protect neighboring AHU sections against discharged dirt.
In order to achieve max. heating output of the heater, it must be well vented. Venting plugs are
designed to do so and they are placed on heater’s collectors.
During the AHU standstill, flow of the heating medium should be reduced to minimum so as
temperature inside the AHU does not 60ºC. Exceeding this value may lead to damage of
some elements or subassemblies (motor, bearings, plastic elements, etc.) installed in the
neighboring sections.
7.3.2 Electric Heater
Electric heater's battery consists of bare heating coils. During AHU operation, when the heater does
not work, dust may settle onto the heating coils. Once the heater is turned on again, strong
contamination may cause smell of burning dust or even preliminary fire danger may appear. Check
regularly (every 4 months) and especially before starting a heating period, any electric connections,
condition of heating elements and their contamination level. Any possible contamination should be
removed with a vacuum cleaner with soft suction nozzle or with compressed air.
Wet cleaning of electric heater is forbidden!
Also check operation of overheating protection in case of lack of air-flow. Air speed should not be
lower than 1.5 m/s.
7.3.3 Water or glycol cooler
Contamination level of the cooler should be checked each four months. If necessary, the cooler can
be cleaned applying methods of cleaning the water heater.
Before starting washing protect neighboring AHU sections against discharged dirt.
While checking contamination level, check the condenser status as well as passability of water
siphon. The water siphon should be filled with water before starting up the AHU.
If the condenser is contaminated it should be washed with warm water with some cleaning medium.
In case of glycol cooler check level and density of glycol in the system. In order to achieve max.
output of the cooler, it must be well vented. Venting plugs are designed to do so and they are placed
on cooler’s collectors.
7.3.4 Freon cooler and heater
Maintenance of freon cooler covers the same range as the water heater and cooler. While washing
the freon cooler with warm water, the cooling system should be emptied by sucking off freon to the
container. Otherwise there is a risk of uncontrolled increase of freon pressure and damage of the
cooling system.
7.3.5 Humidifier
Periodic maintenance operations of the humidifier boils down to clean the strainer-type filter on the
water supply pipe at least twice a year, and at least once a year, check the following:
- all wires about aging, cracks, current leakage, etc
- water pipes and joints about aging, cracks and leakage
- if the water pump has abnormal sound or peculiar smell during the running
7.3.6 Cross-flow and counter flow heat exchanger
Check the exchanger every four months and inspect its technical condition as well as contamination
level. Dirt accumulation in plate heat exchangers is often limited to the first 50mm in the exchanger.
Before starting washing protect neighboring AHU sections against discharged dirt.
