Carrier 30RQ EXV problem

[Absorber81]

Hi All. I have 30RQ120 Chiller with AquaSnap Control System.
In cooling mode, the unit is working fine.
In the heat pump:
The unit starts up and gets into position EXV 27% and off for high pressure
EXV on the sensor does not respond - only 27%
I heated the sensor - no reaction - 27% and off for high pressure
In what could be the reason?
Thanks in advance for your help

[install monkey]

Maximum and minimum temperatures
Cooling mode
Water heat exchanger (evaporator) Minimum Maximum
Entering water temperature at start-up °C 6.8 30
Leaving water temperature during operation °C 5 15
Entering water temperature at shut-down °C - 60
Air heat exchanger (condenser)**
Air entering temperature °C 0 46
Heating mode
Water heat exchanger (condenser) Minimum Maximum
Entering water temperature at start-up °C 8* 45
Leaving water temperature during operation °C 20 50
Entering water temperature at shut-down °C 3 60
Air heat exchanger (evaporator)
Air entering temperature** °C -10 35

[Gibbo]

A bit more information would help, does it trip in heat or defrost mode. Can you supply a running log of what the unit is doing when it trips.