system
air
53
Maintenance
In order to ensure smooth performance of heat exchangers, the following operations should be carried out regularly:
•
Check that the steam and water connections are leakage-free and that air joints are firmly mounted and leakage-
free.
•
Check the venting fan operation. In the event of disturbances in the medium flow through the heat exchanger or
the formation of air cushions, vent the piping system.
•
Check the operation of the heat exchanger automatic anti-frost protection.
•
Periodically check the operation of the automatic shut-off of the supply of steam into the heat exchanger with the
unit stopped.
•
Check the continued operation of the fan (for 3 to 5 min) after the unit is stopped to protect the electric motor
against overheating.
•
Regularly check the heating coil blades for dust build-up. Dust or scale build-up on blades reduces the heat
exchanger capacity. Clean the blades at regular time intervals – approx. every 500 hours of operation. To clean the
blades, blow them with compressed air in the direction opposite to the air flow direction. If such cleaning proves
insufficient, disconnect the heating coil, slide it out and wash with low-pressure water or steam. Do not use high-
pressure water or steam in order to avoid deforming the aluminium blades. If washing with water, the pressure
thereof must not exceed 15 bar and the jet must be directed strictly perpendicular to the blades. Exposure to a
water jet at an angle will damage the blades. This applies even more so to the blades at the edge, since these are
even more fragile. Under no circumstances should you attempt to clean with a hard object.
•
Periodically check the proper operation of the automatic condensate discharge pot.
• Regularly clean the condensate discharge lines.
3.7.7
Electric air heater
Caution
See also section 3.1 General instructions.
The connection of the electric air heater must be carried out
by a qualified professional in accordance with the applicable
regulations.
Connection, commissioning and maintenance to be carried out
according to the manufacturer‘s instructions.
Connection
• Any functional section containing temperature-sensitive materials should be separated from the electric air heater
section by an empty section at least 300 mm in length.
•
The air velocity through the electric air heater must not be less than 1,5 m/s; the air inflow must be evenly distributed
across the entire cross section.
• The maximum operating air temperature is 50 °C.
• Connection terminals in the electric air heater connection box are accessible from the section service side.
•
Lead the electric cables into the connection box through the cable glands and make sure the cable run does not
obstruct the servicing of the adjacent functional sections.
• The electric heating elements are connected to the mains voltage of 3 x 230 V or 3 x 400 V, and achieve surface
temperatures depending on air velocity from 200 up to 500 °C during operation.
•
An air handling unit that includes an electric air heater section must be fitted with an air flow control function.
•
The electric air heater may only be switched on after the fan has started and built up an adequate air flow.
• After the electric air heater has been switched off, the fan must continue to run for 3 to 5 minutes to cool down the
electric heating elements.
• The safety temperature limiter and safety thermostat sensors must always be installed in the upper part of the
electric air heater section – above the electric heating elements, where the temperature reaches the highest levels in
the event of air flow interruption.
• The electric air heater is not waterproof, therefore, the electric air heater section must not be installed in a location
exposed to water or water steam.
