de Jong Duke COEX 9CND SERIES, Technical Manual

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5.5 Water flow meter/water counter
The water flow meter measures the quantity of the water
flowing through the hot water pressure system.
Three functions are based on the water flow meter:
1. The water dosages for the consumptions are based on
quantity of the pulses generated by the flow meter.
2. During the start up procedure it is detected if water is flowing
into the system. If not, the machine will stop working and show
the error messages “start-up problem” and “no water
connected”
3. The amount of heating of the boiler is, besides the
measurement with the temperature probe, also based on the
quantity of incoming water.
The water flow meter is built in between the pressure reducer
and the pumps. It is a small turbine which produces electrical
pulses. Each 360º rotation produces 2 pulses in the sensor (Hall
element). The pulses are detected by the control system.
The tube to the water flow meter must be connected in the right position; the
flow meter cannot detect water in the reverse mode. There is a small arrow on
the water flow meter which shows the right direction.
The water flow meter is a 1.8 mm type.
Each pulse is about 0.8 ml of water.
Electrical connections/wire colors:
Number Wire color
function
1 Red-white Common (+)
2 Green-purple Null (0)
3 Blue-black Signal to the IO board