Daikin RZQ Series FCQ20EVA Service Manual page 164

Troubleshooting by Remote Controller
CHECK 3
Evaluation of Abnormal Low Pressure
Abnormally low pressure level is mostly caused by the evaporator side. The following contents are provided
based on field checking of service engineer. Further, the number is listed in the order of degree of influence.
In Cooling
Check items (Possible causes)
Does the outdoor unit fan run normally?
Is the indoor unit filter clogged?
Is there clogging before or after the EV (capillary)?
Is the check valve clogged?
Is the indoor unit installed under such conditions that
short circuit easily occurs?
Is the refrigerant shortage?
In Heating
Check items (Possible causes)
Does the outdoor unit fan run normally?
Is the outdoor unit heat exchanger clogged?
Is the outdoor unit installed under such conditions that
short circuit easily occurs?
Is there clogging before or after the EV (capillary)?
Is the check valve clogged?
Is the refrigerant shortage?
155
Judgement
Visual inspection
Visual inspection
Check if there is a temperature difference before and
after EV (capillary).
Check if the main valve unit of EV operates (by noise,
vibration).
Check if there is a temperature difference before and
after check valve.
 If YES, the check valve is caught.
Visual inspection
Conduct refrigerant collection and vacuum drying, and
then add proper amount refrigerant.
Judgement
Visual inspection
Visual inspection
Visual inspection
Check if there is a temperature difference before and
after EV (capillary).
Check if the main valve unit of EV operates (by noise,
vibration).
Check if there is a temperature difference before and
after check valve.
 If YES, the check valve is caught.
Conduct refrigerant collection and vacuum drying, and
then add proper amount refrigerant.
SiME281501E
Service Diagnosis