59
CONTROL SYSTEM
Remote Cooling - Heating
This function allows remote switching of the machine operating mode and is enabled only if Pa H49 = 1. The digital input used is ID11.
If the input is active (contact open) the selected operating mode is Heating.
Automatic mode
This function enables automatic switching between the cooling and heating modes according to the inlet air temperature and set
points. It can be activated by means of the remote thermostat (EKF400 RT type keyboard) or setting the parameter Pa H49 to 2.
Recording hours of operation
The controller can record in the non-volatile memory the hours of operation of :
• compressors
• internal fan
The internal resolution is in minutes. The values are visible in the special menu with label Ohr (see menu structure).The whole value is
displayed for values below 999 hours; for higher values the hours/100 are displayed and the decimal point lights up.
Example. 1234 hours are indicated as follows :12.3
The hours are reset by pressing the set button for 2 seconds, while the hours of operation are displayed. In case of a power failure the
last hour fraction recorded is set to 0, therefore the hour count is rounded off to the lowest gure. (es. 35.48 = 35.00).
Power failure
In case of a power failure, when the power is restored the control goes to the status existing prior to the failure. If a defrost is in progress
the procedure is cancelled. All timings in progress are cancelled and reinitialised.
Probe characteristics
NTC10K-25°C type temperature probes are
used.
When the probe bulb is at the temperature of
25°C the electrical resistance at the probe ends
measurable with a multimeter is approx. 10 kΩ.
The thermistor of these probes is at a negative
temperature: the electrical resistance value
decreases with the increase in temperature.
To verify if a probe is faulty or disconnected,
check the agreement between the resistance
value in kW and the temperature of the bulb in °C
according to the following table.
For a reliable check is not essential to control
every single value but just several sample values.
If the instrument indicates infinite resistance it
means that the probe is disconnected.
Example. With a temperature of 20°C on the
probe, the ohmmeter display will indicate approx.
12.21 kΩ.
Heating
HEATING
Pa b02
Inlet
air
Set point
HEATING
Cooling
COOLING
Set point
COOLING
Pa b01
Temperature Resistance Temperature Resistance Temperature Resistance
[°C]
[k
Ω]
[°C]
[kΩ]
[°C]
[kΩ]
0 25,7950 20 12,2110 40 5,7805
1 24,8483 21 11,7628 41 5,5683
2 23,9363 22 11,3311 42 5,3640
3 23,0578 23 10,9152 43 5,1671
4 22,2115 24 10,5146 44 4,9774
5 21,3963 25 10,1287 45 4,7948
6 20,6110 26 9,7569 46 4,6188
7 19,8546 27 9,3988 47 4,4493
8 19,1259 28 9,0539 48 4,2860
9 18,4239 29 8,7216 49 4,1287
10 17,7477 30 8,4015 50 3,9771
11 17,0963 31 8,0931 51 3,8312
12 16,4689 32 7,7961 52 3,6906
13 15,8644 33 7,5100 53 3,5551
14 15,2822 34 7,2343 54 3,4246
15 14,7213 35 6,9688 55 3,2989
16 14,1810 36 6,7131 56 3,1779
17 13,6605 37 6,4667 57 3,0612
18 13,1592 38 6,2293 58 2,9489
19 12,6762 39 6,0007 59 2,8406
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