AERMEC TX Handbuch Seite 23

VALVE ON/OFF FUNCTION
If a shut-off valve is installed (dip1 ON), the position of the probe can be managed both upstream and downstream of the valve itself (on the standard
position available in the heat exchanger). The difference between the two options lies in how ventilation is managed. If the water probe is upstream of
the valve (dip2 ON) or isn't installed, there is an exchanger pre-heating function that enables the fan 2'40'' after the first opening of the valve.
For this exchanger pre-heating function, the valve in question is Y1 in the case of a 2-pipe system (dip5 Off) or Y2 with a 4-pipe system (dip5 On). The
fan inhibition time is then calculated automatically according to how long the valve has remained closed; in this way, it can vary from a minimum of 0'
00'' to a maximum of 2' 40''. This ventilation enabling delay in relation to the opening of the valve is reset if the electric heater is enabled, the purpose
being to guarantee greater safety for the user.
The figure below indicates the valve operating logic if the thermostat is used with thermostat-controlled ventilation logic or modulated logic. As you can
see, in HEATING mode the valve is used by exploiting the capacity of the terminal to dispense heat even when ventilation is disabled (stack effect).
On the one hand, this takes advantage of the stack effect, and on the other it avoids the continuous opening and closing of the valve (that takes a few
minutes to respond), which means the water in the terminal is always circulating during normal operation.
In COOLING mode, thermostat control of the valve is not synchronised with that of the fan. This helps take full advantage of the cooling capacity of the
machine, and ensures more precise room temperature control.
If the thermostat uses continuous ventilation, the valve operating logic is as shown below:
COOLING/HEATING MODE CHANGEOVER
SEASON CHANGEOVER ON THE BASIS OF THE WATER
If the thermostat is configured to be used without a valve (dip 1 OFF) or with a probe upstream from the valve (dip 2 ON), the measured water
temperature is the one effectively available on the terminal so the season is forced to Heating or Cooling according to that temperature. The
season changeover thresholds are shown in the figure below (where you can also see the meanings of dip 4).
In this configuration, the indications of the left-hand LED correspond to the active mode (red for Heating, blue for Cooling, and blue/pink or
red/pink in the disabled area). Ventilation is only enabled if the water temperature is suitable for Heating mode or Cooling mode. This avoids
unwanted cold ventilation during the winter, and controls the activation and deactivation of all the terminals on the basis of the effective state
of the water available (centralised control of the On-Off and Heating-Cooling commands).
SEASON CHANGEOVER ON THE BASIS OF THE AIR
There are certain types of system in which the season changeover depends on the air:
• 2-pipe systems with a water probe downstream of the valve
• all 2-pipe system without a water probe
• 2-pipe systems (cooling only) + Heater (heating only)
• 2-pipe systems + Heater used for integration/replacement
• All 4-pipe systems
The season changeover takes place on the basis of the following criterion:
- Cooling mode: if the room temperature is lower than the set value and the difference is equal to the dead band (2°C or 5°C), heating mode is
activated
- Heating mode: if the room temperature is higher than the set value and the difference is equal to the dead band (2°C or 5°C), cooling mode is
activated
The dead band is defined via Dip 7 - i.e. if Dip 7 is OFF, the dead band is 5°C, whereas if Dip 7 is ON, the dead band is 2°C.
Heating setting
Valve
Heating setting
Valve
Ventilation
Vantilazione
Cooling
Freddo
disabled
disabilitata
17°C 22°C
22°C 25°C
Cooling setting
Dead band
Cooling setting
Valve
Dead band
Heating
Caldo
35°C 39°C Normal band (Dip 4 OFF)
31°C 35°C Reduced band (Dip 4 ON)
Valve
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