Low Pressure [Mpa] - Daikin VRV IV+ Service Manual

2 | Troubleshooting
Service manual
32
Trigger
Low pressure control (by
sensor) active due to
<safety value certain
times within certain
minutes, see "6.6 Safety
devices" [ 4 449].
To solve the error code
INFORMATION
It is recommended to perform the checks in the listed order.
1 Check that all stop valves of the refrigerant circuit are open. See
"4.2 Refrigerant circuit" [
Possible cause: Closed stop valve in the refrigerant circuit.
2 Perform a cross‑wiring check of the F1‑F2 transmission wiring between the
indoor units and outdoor unit. Set field setting 2‑5 of the outdoor unit to 1 to
start the indoor units connected to that outdoor unit on forced fan operation,
see "6.9 Field settings"
connected to a different outdoor unit) is operating, this indoor unit is
connected to the wrong outdoor unit (cross‑wired). Correct the wiring
between the indoor unit(s) and outdoor unit.
Possible cause: F1‑F2 transmission wiring is cross‑wired with another outdoor
unit system.
3 Check if the refrigerant circuit is correctly charged. See
4
circuit" [ 363].
Possible cause: Refrigerant shortage.
4 Check for the presence of humidity in the refrigerant circuit. See
"4.2 Refrigerant circuit" [
Possible cause: Humidity in the refrigerant circuit.
5 Check if the refrigerant circuit is clogged. See
Possible cause: Clogged refrigerant circuit.
6 Perform a check of the evaporator side expansion valve. See
4
valve" [ 244].
Possible cause: Faulty evaporator side expansion valve.
7 Check the required space around the outdoor unit heat exchanger. See
"4.3 External factors" [
Possible cause: Insufficient air flow or air by‑pass due to required space
specifications not met.
8 Clean the outdoor heat exchanger. See "5 Maintenance" [
Possible cause: Dirty outdoor heat exchanger.
9 Perform a check of the refrigerant low pressure sensor. See
low pressure sensor" [
Possible cause: Faulty refrigerant low pressure sensor.
10 Perform a check of the main PCB. See
Possible cause: Faulty main PCB.
Effect
Unit will stop operating.
4
363].
4
[ 455]. If any other indoor unit (that should be
4
363].
4
372].
4
333]
"3.11 Main
Reset
Manual reset via user
interface.
Automatic Reset when
Low Pressure >reset
value, see "6.6 Safety
4
devices" [ 449].
"4.2 Refrigerant
"4.2 Refrigerant circuit" [
"3.7 Expansion
4
374].
"3.18 Refrigerant
4
PCB" [ 290].
REYQ8~20+REMQ5U7Y1B
VRV IV+ Heat Recovery
ESIE18-15B – 2020.05
4
363].