Other Symptoms - Daikin VRV IV+ Service Manual

2 Troubleshooting
Symptom
Disturbing operation noise and
vibration
2.4.21

Other symptoms

Mode: Cooling
Dirty air filters
Air by-pass between air inlet/outlet
@indoor unit
Non condensables (i.e air) in
refrigerant
*1
Moisture in refrigerant
Impurities (dust, burr, ...) in
*2
refrigerant
Refrigerant shortage
*3
Insufficient compression
Mode: Heating
Dirty air filters
Air by-pass between air inlet/outlet
@indoor unit
Non condensables (i.e air) in
refrigerant
*1
Moisture in refrigerant
Impurities (dust, burr, ...) in
*2
refrigerant
Refrigerant shortage
*3
Insufficient compression
*1
Water in the refrigerant freezes inside the electronic expansion
valve and is basically the same phenomenon as pump‑down.
*2
Dust, burr in refrigerant clogs refrigerant filters and results with
symptoms of pump‑down operation.
*3
Pressure difference between high and low pressure decreases.
Service manual
76
https://daikin-p.ru/catalog/vrv-daikn/naruzhnye-vrv-bloki-daikin
Possible failure
Faulty Inverter PCB output
Installation faults
Wet operation
Flash gas on liquid piping
Low pressure
Lower than normal
Lower than normal
Higher than normal
Lower than normal
Lower than normal
Lower than normal
Higher than normal
Low pressure
Higher than normal
Higher than normal
Higher than normal
Lower than normal
Lower than normal
Lower than normal
Higher than normal
Root cause
Instable output voltage from
inverter PCB to compressor(s)
Unit not installed according to
installation manual
Liquid compression
Expansion valve fault of refrigerant
shortage
High pressure
Lower than normal
Lower than normal
Higher than normal
Lower than normal
Lower than normal
Lower than normal
Lower than normal
High pressure
Higher than normal
Higher than normal
Higher than normal
Lower than normal
Lower than normal
Lower than normal
Lower than normal
Repair
Check Power Supply, see
"4.1 Electrical circuit" on page 130.
Restore the power supply in
conform with the requirements.
Check inverter PCB(s) and
perform a power transistor check,
see "3.8 Inverter PCB" on
page 99. Check compressor(s),
see "3.2 Compressor" on page 82
Check installation manual. Correct
necessary items. Leave required
space to outdoor unit for operation
Check thermistors. See
"3.17 Thermistors" on page 128.
Check for refrigerant overcharge,
see "4.2 Refrigerant circuit" on
page 133. Check expansion valves
for heat exchanger that run as
evaporator. Check superheat.
Recover refrigerant and weigh.
Charge refrigerant to the correct
amount
Check expansion valves for heat
exchangers that run as evaporator.
Check superheat. Recover
refrigerant and weigh. Charge
refrigerant to the correct amount
Running current
Lower than normal
Lower than normal
Higher than normal
Lower than normal
Lower than normal
Lower than normal
Lower than normal
Running current
Higher than normal
Higher than normal
Higher than normal
Lower than normal
Lower than normal
Lower than normal
Lower than normal
RYYQ+RYMQ+RXYQ8~20U7Y1B
VRV IV+ Heat Pump
ESIE18-14 – 2019.07