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B.2.
Control Logic Specifications
Fan Coil Unit ON/OFF
There are 3 ways to turn the system on or off:
a)
By the ON/OFF button on the remote handset or wired wall pad.
b)
By the programmable timer on the handset or wired wall pad.
c)
By the manual control button on fan coil unit.
Auto Restart
The system uses a non-volatile memory to save the present operation parameters when the system is turned off or in case of
system failure or cessation of power supply.
The restored parameter data-set depends on the type of user interface.
a)
Handset only user interface:
When the power ON signal is received by the fan coil unit and no wired wall-pad is installed, the Mode, Fan Speed, set
temperature will be the same as the handset setting before the last power OFF.
b)
Wall-pad only OR wall-pad and handset user interface:
When the power ON signal is received by the fan coil unit and a wired wall-pad is installed, the Mode, Fan Speed, set
temperature and Timer ON/OFF weekly program will be the same as the wall pad setting before the last power OFF.
2-pipe Control Logic - with Modulating Valve
COOL MODE
When unit is turned on in cooling mode:
a)
If Tr ≥ Ts + 1ºC (Modbus 300033 setting), MTV1 is turned on. AUX1 is closed. Fan is turned on at setting speed.
DA1 is turned on at 10VDC for 2 minutes, then check Ti1:
When Ti1≤8ºC, DA1 output is based on water temperature difference (Ti1/Ti2) and Modbus
parameter 300027 setting PID
calculation. The output is the minimum output (Modbus300015 setting) ~10VDC.
When 8<Ti1≤10ºC, DA1 output is based on water temperature difference (Ti1/Ti2) and Modbus parameter 300027 setting
minus 1 PID calculation. The output is minimum output (Modbus300015 setting) ~10VDC.
When 10<Ti1≤12ºC, DA1 output is based on water temperature difference (Ti1/Ti2) and Modbus parameter 300027 setting
minus 2 PID calculation. The output is minimum output (Modbus300015 setting) ~10VDC.
When
12<Ti1≤15ºC, DA1 output is based on water temperature difference (Ti1/Ti2) and Modbus parameter 300027 setting
minus 3 PID calculation. The output is minimum output (Modbus300015 setting) ~10VDC.
When 15<Ti1≤28ºC (Modbus 300017 setting), DA1 output is kept
at 10VDC.
When Ti1>28ºC (Modbus 300017 setting), DA1 output is at minimum (Modbus300016 setting). and report pre-heat alarm.
b)
If Tr < Ts- 1ºC (Modbus 300033 setting), then cool operation is terminated and MTV1 and AUX1 are turned off. Indoor
fan runs at set speed. DA1 output is 0VDC.
When unit is turned off, MTV1 and AUX1 are off. DA1 is 0VDC. Fan is turned off after 30s.
The range of Ts is 16 - 30ºC.
Indoor fan speed can be adjusted to low, medium, high and auto.
LOW TEMPERATURE PROTECTION OF INDOOR COIL IN COOLING MODE
If Ti1
≤ 2 ºC for 2 minutes, MTV1 is turned OFF. DA1 is 0VDC. Indoor fan is set at Medium speed if fan runs at low speed.
If Ti1 ≥ 5ºC for 2 minutes, MTV1 is turned ON. DA1 is set to original status. Indoor fan is changed to set speed.
FAN MODE
Indoor fan speed can be adjusted to low, medium and high. If fan speed is set to auto by Modbus, fan will run at low speed.
HEAT MODE
Without Electrical Heater (Modbus300043=0)
When unit is turned on in heating mode:
a)
When
Tr ≤ Ts
- 1 ºC (Modbus 300033 setting), MTV1 and AUX2 are turned on. DA1 is at 10VDC for 2 minutes, check Ti1:
If Ti1 < 28ºC (Modbus 300017 setting), fan is turned on at low speed. DA1 is at 10VDC.
If 28ºC<Ti1< 28(Modbus 3000017 setting) + 4ºC, fan is on at original state. DA1 is at original state.
If Ti1
≥ 28(Modbus 3000017 setting) + 4ºC, fan is on at setting speed. DA1 output is based on water temperature difference
(Ti1/Ti2) and Modbus parameter 300027 setting PID calculation. The output is minimum output (Modbus300015 setting)
~10VDC. If Ti1 sensor is damaged, fan runs at setting speed.
b)
When Tr > Ts+1 ºC (Modbus 300033 setting), MTV1 and AUX2 are turned off. DA1 is at 0VDC. fan will run at lowest
speed.
When unit is turned off, MTV1 and AUX2 are turned off. DA1 is at 0VDC. Fan is turned off after 2 minutes.
With Electrical Heater as booster (Modbus300043=1)
2019-IOM-SWC-V-EC-I-001
