Evaluation Of Abnormal Low Pressure - Daikin R71FUV1 Service Manual

Si20-701_B
CHECK 5

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 operation
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?
∗ Heat Pump model only
Is the LPS normal?
Is the indoor unit installed under
such conditions that short circuit
easily occurs?
Is the refrigerant shortage?
466
Troubleshooting by Remote Controller
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.
Check continuity using a tester.
Visual inspection
Conduct refrigerant collection and
vacuum drying, and then add
proper amount refrigerant.