Daikin EUWL KZW1 Series Service Manual page 98

Checking the Inputs and Outputs
3.4 Checking the Digital Inputs and Outputs
1
Troubleshooting
Input route to PCB
3 3
Output route from
PCB
4
5
3–16
In most cases a malfunction occurs in the unit itself and not in the control circuit of the unit. However,
if a malfunction does occur in the control circuit, measure the relevant signals using the schematic
input route shown below.
The block diagram below shows the digital input route from the transducer (e.g. thermostat,
pressostat, reverse phase, etc.) to the PCB input.
Unit Transducer
Voltage free
contact
The output is generated by the PCB. If a device does not operate, you should find the relevant output
signal from the PCB in order to decide whether the PCB or the device needs replacement.
The block diagram below shows the output route.
PCB output
Voltage free
contact
Relay contact
Relay
230 V (coil) Voltage free
contact
Control relay
230 V (supply)
ESIE-0303
PCB input
24 V AC
Device
E.g. fan, valve...
Part 3 – Troubleshooting