Checking The Digital Inputs And Outputs - Daikin EUWA/Y5-30HB/C(Z) Service Manual

ESIE98–06A
3.3

Checking the Digital Inputs and Outputs

Input route In the following block diagram the digital input route from the transducer (e.g. thermostat, pressostat,
reverse phase, etc.) to the PCB input is shown.
Troubleshooting In most cases a malfunction occurs in the unit itself and not in the control circuit of the unit. If, however,
the latter is the case, then you should measure the relevant signals using the schematic input route
shown above.
Output route The output is generated from 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 output
route is shown in the block diagram below:
Part 3 – Troubleshooting
UNIT TRANSDUCER
voltage free
contact
PCB OUTPUT
voltage free
contact
RELAY
230 V (coil)
C O N T RO L R E L AY
230 V (supply) e.g. fan, valve
Checking the Inputs and Outputs
RELAISCONTACT PCB INPUT
voltage free
contact 24 V AC
DEVICE
1
3 3
4
5
3–17