Daikin FTXA25AW - Page 159

3 | Third party components
Service manual
159
FTXA20~50A(W)(S)(T) + FTXA20~50B(B)(S)(T) + RXA42+50A +
RXA20~35A(9) + RXA42+50B
Split Stylish R32
ESIE18-03D – 2021.05
To check if the refrigerant circuit is clogged
Prerequisite: Stop the unit operation via the user interface.
Prerequisite: Turn OFF the respective circuit breaker.
1 Wait for the refrigerant to reach the outdoor temperature.
2 Check that all field piping is done according to the refrigeration practice and
installer reference guide:
▪ Correct piping diameters
▪ Piping distance limits are followed
▪ NO pipes are squeezed
▪ NO short radius bends
3 Connect a manometer to the service port.
4 Turn ON the power of the unit.
5 Activate Heating operation via the user interface.
6 Read the pressure on the pressure gauge. If, at the start of the unit operation,
the pressure is high or very low, the refrigerant circuit might be clogged.
7 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
"3.2.2Repair procedures"[4162].
No Return to the troubleshooting of the
specific error and continue with the
next procedure.
To check if the refrigerant circuit is correctly charged
Due to the relationship to pressure control and electronic expansion valve control,
the amount of refrigerant needs to be examined according to operating conditions.
Refer to the procedures shown below for correct examination.
Refrigerant overcharge diagnosis
1 High pressure rises. Consequently, overload control is conducted to cause
insufficient cooling capacity.