EN/07.2013/58/44
If internal humidity probe isn’t connected, the behaviour of fan is under the humidity switch control. The fan will be at
100% of its speed if the humidity switch is “ON”, otherwise it will be at min of its speed (M90).
If the internal humidity probe is connected, the behaviour of fan will be as it is described below.
The minimum speed of the evaporator fan corresponds to the highest humidity level, while the maximum value
corresponds to the lowest humidity value.
The fan speed is proportionally changed between the two values.
Fan going to M90 MIN SPEED (or, if heater is on, to M91): Fan going to M92 MAX SPEED:
If RH > DS + 20% (BHU)
If RH > S05 + M72 * S08
If RH < DS + 2% (BHU)
If RH < S05 + M73 * S08
Fan control for antifreeze
Special parameters involved:
• M90 MIN EVAPORATOR FAN SPEED: pre-set = 30%
• M91 MIN EVAPORATOR FAN SPEED with Heater on; pre-set = 70%
• M92 MAX EVAPORATOR FAN SPEED: pre-set = 100%
Temperature limit for setting fan min speed and fan max speed are fixed.
• M95 EVAP. TEMP. FOR MIN EVAP. FAN SPEED: pre-set= 10°C
• M96 EVAP. TEMP. FOR MAX EVAP. FAN SPEED: pre-set= 5°C
The fan speed depends on evaporator temperature: if TE is too low (default 10 degrees), speed starts to increase till to
reach 100% at 5°C.
The fan speed is proportionally changed between the two values.
Fan going to M90 MIN SPEED (or, if heater is on, to M91): Fan going to M92 MAX SPEED:
If TE > 10°C (TE > M95) If TE < 5°C (TE > M96)
If TE is not present, the anti-freezing control goes on the TM. If also the TM is not present, the anti-freezing control is
bypassed.
4.2.3. Heater logic
The parameters involved are:
• S01 COOLING SET POINT: pre-set= 25°C
• S07 HEATING BAND: pre-set= 5°C
• M65 HEATING ELEMENTS START (% of band): pre-set= 50%
• M66 HEATING ELEMENTS STOP (% of band): pre-set= 0%
• M76 HEATERS ENABLE WITH DEHUMIDIFICATION: pre-set= YES
The heaters start during the dehumidification if enabled by M74 set-up parameter. Their effect is to maintain TI temperature
to S01 set point, during the compressor dehumidification action.
Heaters start (digital output R3) when the temperature: Heaters stop (digital output R3) when the temperature:
T-ON = CS - [50% B]
T-ON = S01 - [M65 * S07]
T-OFF = CS - [0% B]
T-OFF = S01 - [M66 * S07]
Note that the status of heater (on or off) will affect the minimum speed used by the system for the evaporator fan (system
uses different parameters, M90 or M91, for minimum evaporator fan speed according to heating element status).
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