37
12. Malfunctions
12.1 Inspection instructions
Bypass
• If 230V AC is measured at connection DO3H between L and N, the
valve should open/be opened.
• If 230V AC is measured at connection DO4H between L and N, the
valve should close/be closed.
• Check the connections between the main board and the bypass (plug).
Intake and exhaust fan
• Inspect the fan for dirt or mechanical damage.
• In the case of an E1 or E2 malfunction, check the wiring. If this is
correct, the fan, the board, the fuse or the power supply is defective.
• The fans’ supply voltage is 48V DC. If this is not available, disconnect
the 48V DC cord and measure the supply again.
• The control voltage for the fans is between 0 and 10V DC. This voltage
can be measured on the main board at AO1L or AO2L between "+"
and GND.
Three-position switch
Check the switch as follows;
• Detach wires L2 and L1 on the main board. The fans run in mode 1.
• Detach wires L3 and L2 on the main board. The fans run in mode 2.
• Detach wires L3 and L1 on the main board. The fans run in mode 3.
Boards
• If the fans respond to the switch and the display shows no data or
unusual data, then is the display defective. Also check the connection
between the main board and the display.
• If the fans do not respond to the switch and the display shows no data,
then is the main board or the display(operating panel) defective.
• If the main board is replaced the unit must be set up once again.
PTC sensor
• Check the position of the sensor and the wiring. If this is correct, the
sensor should be replaced.
Heat exchanger
• Check whether the heat exchanger is damaged or soiled. See
Maintenance
Filters
• In the case of filter malfunction, remove the filters, clean them and
replace if necessary.
English
