8.2 Bypass
Inspection
Instructions
If 230 V AC is measured between DO3H and N,
the flap must open / be open.
If 230 V AC is measured between DO4H and N,
the flap must close / be closed.
Check the connection between pcb and bypass.
Air intake and air exhaust fan
Check the fans for soiling or mechanical damage.
If the fault E1 and/or E2 is displayed, check the
wiring. If the wiring is OK, then the fan is defective.
The supply voltage to the fans is 230 V. The
control voltage of the fans lies between 0 and 10
V DC. This voltage can be measured at the
terminals AO1L and AO2L on the pcb.
Printed circuit boards
If the fans react to the 3-position switch and the
display shows no or wrong values, then the
display is defective. Check the connection
between display and pcb.
If the fans do not react and the display shows no
values, then the pcb or the operating panel is
defective.
If the pcb is replaced, the unit has to be set up
again. If a protocol of the last setting is available,
the set values can also be taken from the protocol.
PTC thermistor
Check the thermistor and the wiring. If they are
OK, the thermistor must be replaced. See table of
thermistor values.
Temp.°C
-50 -40 -30 -20 -10
0
10
20
25
Ohm
515 567 624 684 747 815 886 961 1000
Temp.°C
30
40
50
60
70
80
90
100
Ohm
1040 1122 1209 1299 1392 1490 1591 1696
Heat exchanger
Inspect the heat exchanger for damage and
soiling. See also chapter “
Maintenance / Care
”.
Three-position switch
Check the function as follows:
Disconnect the cables at terminals L2 and L1 on
the pcb. The fans run at level “
1
”.
Connect terminals L3 and L2 on the pcb. The fans
run at level “
2
”.
Connect terminals L3 and L1 on the pcb. The fans
run at level “
3
”.
Filter
In the event of a filter malfunction, pull out the filters
and clean or replace. See also chapter 7
“
Maintenance / Care
”.
EMC
If the unit causes interference to the television or
stereo system, the EMC filter must be replaced.
9. END OF LIFE PROVISIONS
At the end of the unit’s service life, contact the
supplier for information on adequate disposal. The
statutory regulations in force at the time must be
observed.
