Thermotechnic multisplit fault codes

Has anyone ever had any dealings with Thermotechnic units, especially with the fault codes? My customer thinks it's about 10 years old but uses R410 and has Daikin compressors so it's not a cheap system. The initial fix was just a capacitor and everything seemed fine for an hour before the compressor switched off and displays 4 flashes on the timer light. It's installed in an Apartment block and I just had an idea that it may blocked drain sensor. It's a normal split system and I'm not sure how common it is to include a sensor in these types.