Ductwork; Final Inspection; Maintenance - Komfovent DOMEKT Series Installation And Service Manual

4.3. Ductwork

The air flows in/out air handling unit through ductwork. We recommend using galvanized steel (Zn 275 gr/m
ductwork, to ensure easy cleaning and durability. It is necessary to use the ductwork system with low air flow
rate and small pressure drop to have necessary air volume and low sound level and save the energy. The
appropriate sound attenuators will reduce the noise level of the fans in the premises. All ductwork should be
insulated with 50–100 mm thickness insulation to avoid the condensation.
Note: temperature sensor B1 has to be mounted in the supply air duct under electric heater (see the func-
tional diagram in Control System Electrical Installation and Operation Manual). It is necessary to leave space
in straight air duct for sensor mounting and guarantee the space for maintenance and service work. Minimal
space between the unit and B1 sensor is the space of double air duct diameter.

4.4. Final Inspection

After installation of the unit, a thorough inspection should be carried out. This should include inspecting
the inside of the unit and removing debris and tools, which may have been left behind by on site contractors.
Replace any panels, which may have been removed and close all access doors, ensuring that the door sealing
gaskets have not been damaged.

5. MAINTENANCE

It is recommended to carry out routine maintenance of the air handling unit 3–4 times per year. With units
mounted on ceilin do not release the door to the key to open the door. Do not release the door to swing freely,
but open it slowly at a 90 degree angle. Be careful while opening, because clogged filters might fall out.
Besides preventive maintenance inspection, the following operations should be performed:
1. Rotary heat exchanger check. Inspection of the rotary heat exchanger is performed once per year. Free
rotation of the rotary heat exchanger, continuity of the rotating belt, absence of damages of the rotor drums
and the seal gasket are checked. It is necessary to check the stretch of belt. Free belt will slide and the
efficiency of rotary heat exchanger will fall down. To reach maximal efficiency, rotor must turn at least 8
times per minute. Polluted heat exchanger will decrease efficiency. Clean heat exchanger with an air blast
or wash with tepid water. Check out water falling on the electric motor.
2. Plate heat exchanger check. Inspection and dedusting of the plate heat exchanger is performed once per
year (it is removed from the unit and blown with an air blast or washed with tepid water).
Plate heat exchanger cleaning. If plate heat exchanger cleaning by compressed air is not effective, it can
be washed with soapsuds, or if needed – use degreasing soak for metal (aluminum) cleaning. Leave plate
heat exchanger to dry in a warm place. It can be mounted only when it is absolutely dry.
Note: plate heat exchanger may be replaced with summer cassette (for units without by pass), when re-
cuperation is needless.
3. Fans check (once per year). Polluted fans decrease efficiency.
Fans should be carefully cleaned with textile or soft brush. Do not use water. Do not break balance. Check
if direction of fan turns is right, because wrong direction of turns gives only 30 % rating. Check if fan freely
rotates and is not mechanically damaged, if impeller does not touch suction nozzles, fan does not spread
noise, the pressure tubes are connected to the nozzle (if it is required), mounting bolts are screwed.
The rubber couplings connecting the motor base and the unit should be visually inspected for signs of wear
and replaced as necessary.
Any unusual noise or vibration when the fan is running should be immediately investigated, as this usually
an indication of wear or imbalance in the fan system.
4. Air heater check. Recommended to perform periodical inspection and cleaning of heater. Check the
plates of water air heater. The air heater is cleaned with hoover from supply air side or with air blast from
exhaust air side. If it is very dirty, wash with tepid water, which will not make corrosion of aluminium. Check
if position of return water temperature sensor is right. Check if electric air heater is properly fixed, wires
UAB KOMFOVENT we reserve the right to make changes without prior notice
D_20-07
Ductwork, steelwork and any other services should not be supported
off the unit.
It is recommended to install air dampers in the inlet and outlet ducts. For
ventilation units with water air heater, it is mandatory to use inlet air closing
damper with spring return mechanism.
Before performing any inspection work, check whether the unit is
switched off from the electric power supply.
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