Daikin ALTHERMA HT Service Manual page 167

ESIE09-08B
Troubleshooting
Check No.2
Troubleshooting
Be sure to turn off power switch before connect or disconnect
connector, or parts damage may be occured.
Caution
Is the
stop valve
open?
 Mount a pressure gauge on the low-pressure service port.
 Connect the Service Tool.
 Reset the operation using the remote control, and then restart
the operation.
Are the
characteristics of
the low pressure sensor
normal? (See
Is the
pressure
detected with the PC
board normal?
(See *2.)
· The low pressure sensor is normal, and the pressure
detected with the PC board is also normal.
· The low pressure has really become low.
Refer to "remove the causes by which the low
CHECK 2
pressure has become low".
*1: Make a comparison between the voltage of the pressure sensor (*4) and that read by the
pressure gauge.
(As to the voltage of the pressure sensor, make measurement of voltage at the connector,
and then convert it to pressure.)
*2: Make a comparison between the low pressure value checked with the Service Tool
and the voltage of the pressure sensor (see *1).
*3: Make measurement of voltage of the pressure sensor.
Micro controller
A/D input
Make measurement of DC voltage between these wires. (*4)
:  Refer to information on page 209.
Troubleshooting by Indication on the Remote Controller
NO
YES
NO
*1.)
YES
NO
YES
+5V
Connector for low pressure sensor
(Blue)
(4)
(3)
(2)
(1)
Open the stop valve.
Replace the low pressure sensor.
Replace the control PC board (A4P). .
Red
Black Low
pressure
White sensor
155