Daikin Altherma 3 M - Page 278

3 | Components
Service manual
278
EBLA09~16DA + EDLA09~16DA
Daikin Altherma 3 M
ESIE20-06A – 2021.03
Is the water pump working? Action
Yes Return to the troubleshooting of the
specific error and continue with the
next procedure.
No Perform the next step.
7 Stop the unit operation via the user interface.
8 Unplug the power supply connector from the water pump.
9 Turn ON the power of the unit.
Activate the water pump.
10 Remove the cap from the power supply connector and measure the voltage
between L ‑ N. The voltage MUST be 195~253VAC.
Is the measured voltage correct? Action
Yes Skip the next step(s) and continue with
the measurement of the PWM signal.
No Continue with the next step.
11 Unplug the water pump connector X16A and measure the voltage between
pins 3–5 on the hydro PCB. The measured voltage MUST be 195~253VAC.
Is the measured voltage correct? Action
Yes Replace the power supply wiring
harness between the water pump and
the hydro PCB, see "3.24.2Repair
procedures"[4279].
No Perform a check of the hydro PCB, see
"3.12.1Checking procedures"[4160].
12 Connect the power supply connector to the water pump.
13 Unplug the PWM signal connector from the water pump.
14 Remove the cap from the PWM signal connector and measure the PWM signal
between the PWM‑GND.
▪ When using an oscilloscope, the measured signal MUST look like the illustration
shown below:
T
t
U
iH
U
iL
T Period of time of complete cycle
t Period of time of high‑level input voltage
U
IH
High‑level input voltage
U
IL
Low‑level input voltage
d Duty cycle (t/T x 100) [%]
▪ When using any equipment that is capable to measure the duty cycle, the
measured signal MUST show profile A (see illustration below). The PWM signal
(duty cycle) is disproportional to the water pump speed (flow rate) in the range
of 10% to 84% and the speed (flow rate) remains at its maximum value when the
PWM signal (duty cycle) is below 10%.