Carrier 42N Installations- Und Bedienanweisungen Seite 22

Controls
Control functions
ON/OFF
Three fan speeds manually selected
Fan speed automatically selected
Temperature selector
Green LED – cooling operation
Red LED – heating operation
Yellow LED – automatic seasonal changeover
Yellow LED – energy saving
Manual seasonal changeover button
Centralised seasonal changeover button
Automatic seasonal changeover button
Energy saving button
Return air temperature sensor
Temperature sensor located on the board
Cooling / heating valve (2-pipe)
Heating valve (4-pipe)
Cooling valve (4-pipe)
Electric heater
Frost-protection
External contact
Water minimum temperature sensor
Air sampling (periodic fan starting)
Continuous ventilation
Temperature block
Autotest
Type "U" control (See fig.29)
This is an electromechanical control with a 4 position knob for unit
OFF and fan speed regulation (OFF -
This control cannot be used for room temperature adjustment.
Type "A" and "B" control (See fig.30-31)
Type "A" control is used in 2-pipe systems.
Type "B" control is used in 4-pipe systems and 2-pipe systems with
electric heater.
Functions
(type "A" and "B" controls)
Type "A" and "B" controls have a knob to select the temperature,
with a range from 10°C to 30°C, and room temperature is
maintained at the selected value.
Fan operation
With the fan speed selector a, fan mode can be set either manually
or automatically.
In the manual mode it is possible to select three fan speeds (low/
medium/high) according to personal preference.
In the auto mode fan speed is regulated by a microprocessor in the
control in relation to the temperature chosen.
During installation, it is possible to select continuous fan operation
via the switch located on the electronic board (see paragraph "Dip-
20 42N
switch configuration").
Unit extinction during heating mode is delayed by one minute
- - ). to allow for dispersion of residual heat present on the heat
exchanger coil or on the electric heater if installed (only for
type "B" control).
As an option, fan operation can be disabled during heating, via a
water minimum temperature sensor (42N9004), if the water
temperature is below 40°C and during cooling if the water tempe-
rature is above 18°C.
These two functions allow improved comfort levels during winter
and energy saving during summer by turning the fan coils ON and
OFF automatically in relation to the water temperature.
Frost-protection
This function keeps the temperature from dropping below 7°C in
rooms not used for long periods of time.
When this temperature is reached and with the frost protection
function activated by a dip-switch (set during installation) located on
the electronic board (see paragraph Dip-switch configuration) the
control activates the valve(s) and puts the fan on high speed. The
frost protection function, if enabled, is activated even when the
control is in the OFF position.
Energy saving
This function is especially useful when air conditioning at night or in
rooms where the user is likely to be absent for a longer period of
time. In this case, pushing button
cooling by 4°C and lowers it during heating by 4°C.
Enabling this function (yellow LED ON) cuts out other displays.
Type U Type A
raises the temperature during
Type B