AERMEC WMT21 Manuel D'installation page 60

C22: If the buttons are inactive for a few seconds the thermostat returns
to display the room temperature.
When this parameter is set to 1, the thermostat displays the set-point
temperature instead of room temperature.
C23: This parameter set the special function that should be performed on
output 8. Table 6 shows which functions can be performed.
See the paragraph on "Output 8" section for further information.
ROOM TEMPERATURE CORRECT ACQUISITION
For a correct temperature acquisition it is mandatory to remember and
apply the following tips:
- In order to have an accurate room temperature acquisition the controller
must be installed far from heat sources, airstreams or cold walls
(thermal bridges). When the remote sensor is used in conjunction with
the controller, then this note is to be applied to the remote sensor itself.
- When a remote sensor is used, do not use the same duct for signal wires
and power (mains) wires, as the temperature reading accuracy could
be impaired. Wirings can be usefully made with bipolar screened cable,
whose screen is only wired at the regulator side (terminal 14) with
1,5 mm² minimum cross section and 15 m. maximum length.
- In the normal operation with internal sensor, the controller conditions the
signal acquired according an exclusive algorithm designed to compensate
the heat generated from its internal components. From this derives that
the temperature value displayed at turn-on can be actually lower than
the real one. This must be considered a normal behaviour: anyway in
some minutes this difference should decrease down to zero.
- In case the controller should drive with its outputs large loads (whose
current is close to the maximum rated value) it might happen that the
internal components heat gets bigger. This temperature increase could in
turn influence the room temperature acquisition when the internal sensor
is used. This problem is not present when the remote temperature sensor
is used.
- When, for any reason, the room temperature accuracy is considered
unsatisfactory (due to the above mentioned reasons), it can be corrected
with parameter P12.
- When the controller is powered with 230V~ it is mandatory to respect
the live and neutral (L and N) position during wiring.
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