Daikin VRV IV+, Service Manual

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4 | Third party components
Service manual
364
REYQ8~20+REMQ5U7Y1B
VRV IV+ Heat Recovery
ESIE18-15B – 2020.05
c High pressure/low pressure gas stop valve
2 Check if the stop valves are completely open.
The refrigerant circuit stop valves are
open? Action
Yes Return to the troubleshooting of the
specific error and continue with the
next procedure.
No Open the stop valves of the refrigerant
circuit, see
"4.2.2 Repair
procedures" [ 4 368].
To check if the refrigerant circuit is clogged
Prerequisite: Visually check if the refrigerant liquid/gas pipes between the indoor
and outdoor unit are NOT squeezed or bended into too short radius.
Prerequisite: Stop the unit operation via the central controller.
Prerequisite: Turn OFF the respective circuit breaker.
1 Wait for the refrigerant to reach the outdoor temperature.
2 Connect a manometer to the high pressure and low pressure service ports.
3 Turn ON the power of the unit.
4 Activate Heating operation via the Cool/Heat master user interface.
5 Read the pressure on the high and low pressure gauges. If the difference
between high and low pressure >0.2 MPa, the refrigerant circuit might be
clogged.
6 On the refrigerant liquid piping (between the indoor unit heat exchanger and
the outdoor unit heat exchanger (coil)), using a contact thermometer,
measure the temperature before and after every restricting device. If a big
temperature difference is measured (>2.5~4K), an internal pipe obstruction
may be present at this location.
INFORMATION
Focus on positions with a potential risk for clogging such as:
▪
Filters
▪
Valves
▪
Brazing points
▪
…
INFORMATION
A bigger temperature drop before and after the expansion valve can be normal,
however excessive ice is indicating a malfunction of the expansion valve or internal
obstruction of the valve (dirt or ice build up in case of humidity in the system).
Temperature drop found? Action
Yes Replace the clogged part, see
"4.2.2 Repair procedures" [ 4 368].
No Return to the troubleshooting of the
specific error and continue with the
next procedure.