6
E
nglish
The regulatory thermostats PXA R are control panels for controlling
the fan coils equipped with electrical heating elements, to be
installed on the wall or on the machine.
Each control panel can control a single fan coil.
PXA R controls the working of the fan coil on the basis of the mode
chosen, the room temperature and the temperature of the water in the
circuit, to maintain the desired temperature in the room.
The PXA R thermostats can also control fan coils without electrical
heating elements; in this case it is not necessary to use the selector
position
(A), but you must reset the dip switch 10 to disactivate
the characteristics of the working with heating elements. Before
proceeding with the installation, check that the settings of the dip
switches correspond to the type of system being used.
The layout of the dip switches shown in this manual
indicates all the possible system combinations.
This manual describes the conditions for the
installation of fan coils with electric heater inserted
on 2-pipe systems, with the possibility to connect an
On - Off valve to intercept the water that feeds the
battery.
The control panel only consists of mains
voltage (230V) electrical circuits; all the inputs
for the probes and controls must therefore be
correspondingly insulated for this voltage.
The valve servo commands must also be scaled for
230V.
PXA meets the requirement of the Low Voltage
directives 73/23 (EN 60730-1, EN 60730-2-9, EN
60335-1) and electromagnetic compatibility directive
89/336 (EN 61000-4-1, EN 55011, 55022, 55014).
The panel may only be opened and installed by
specialised personnel.
Cut off the supply voltage before removing the lid of
the control panel. Touching live components could
electrocute you. This is particularly true also for the
setting of contacts on the Sw1
and Sw2 cut outs.
The panel comprises:
– (
A
) on-off selector switch, (manual or automatic) fan speed and
heating with electric heater;
– (
B
) temperature selector;
– (
C
) blue / red/ fuchsia LEDs, operation mode (Cooling/ Heating/
Antifreeze/ Autotest)
– (
D
) yellow led, fan coil operation, Autotest.
+
-
C
A
B
D
V1
= Minimum speed
V2
= Medium speed
V3
= Top speed
Heating with heater
OPERATION
The thermostat's job is to keep the temperature set on selector (
B
)
constant in the room.
The selector switch (
A
) in the
OFF
position take two different functions
that can be programmed during installation:
Frost Protection
, with selector (
A
) in the
OFF
position, this prevents
the temperature, in rooms that are not used for long periods, from
falling below 7°C, which would make it difficult to reheat them when
needed.
If the fan coil is fed with warm water it will start in
AUTO
until the
room temperature is 9°C.
The fan coil, with selector (
A
) in
position, if not fed with
warm water, will start up in heating mode with the electric heater at
medium speed (
V2
) until the room temperature reaches 9°C.
The Frost Protection function must be programmed by the installation
engineer.
All Off
, with selector (
A
) in the
OFF
position, the fan coil is
completely switched off.
VENTILATION
In the two-pipe system, the thermostat makes it possible to enable
the heating ventilation only if the temperature of the water exceeds
35° or 39°C (programmable in the installation phase); in the same
way, the ventilation in the cooling mode is only enabled if the
water temperature is less than 17°C or 22°C (programmable during
installation).
Ventilation is delayed compared with the start and turn off
commands.
The functions described on the one hand prevent unwanted cold
ventilation in winter mode and, on the other, allow all the terminals
to come on and go off depending on the temperature of the water.
The ventilation mode is set with selector (
A
).
Manual mode
(selector in position
V1
,
V2
,
V3
) the fan uses the On-
Off cycles at the selected speed.
Automatic mode
(selector in position
AUTO
) the fan speed is
managed by the microcontroller of the PXA R.
The delay between opening or closing of the warm water valve and
the turning on or off of the fan can last for up to 2’ 40”.
Mode using HEATING ELEMENTS
(selector in position
)
The electric heater cuts in if the temperature of the water in system is not
high enough for normal heating operation.
The electrical heating element turns off when the temperature of the
water in the system reaches the temperature for the normal heating
operation of the fan coil.
The fan speed is managed by the PXA R microcontroller that turns off (
) speed
V1
during normal operation with enabled electric heater
(i.e. speed
V2
will be used as the minimum speed).
When the heater is turned on, the ventilation starts up at speed V1
that it maintains for forty seconds, then it goes to normal operation
with the electric heater.
When the electric heater is turned off, the ventilation continues
at speed
V2
for another minute to prevent the electric heater from
overheating.
AUTOMATIC CHANGEOVER, AIR SIDE
The control makes it possible to automatically set the fan coil
functioning mode at heating or cooling.
- In the two-pipe system, no valve systems or those with probe upline
from the valve, the functioning mode change is determined by the
temperature of the water circulating in the system.
- In systems with probe upline from the valve, the operational mode
change is determined by the temperature of the water circulating in
the system if this has a value above the enabling threshold.
- In two-pipe systems with probe downline from the valve, and
in all the systems without water temperature probes, the change
of operational mode is determined by the difference between the
temperature measured in the room and the set temperature.
- With the selector (
A
) in position
, the fan coil is only able to
function in the Heating mode.
Congratulations on your purchase of the Aermec PXA R control panel with
electronic thermostat. Made with high-grade materials in close
compliance with
safety standards, the “PXA R” is easy to use and will be with you
for many years to come.
