Main Protection; Preheating Permitting Condition; Preheating Mode; Preheating Release Condition - Kaisai KFU-09HRDN1-QRC8W Service Manual

8.3 Main Protection

8.3.1 Time delay at restart for compressor
1 minute delay for the 1
8.3.2 Temperature protection of compressor top
The unit will stop working when the compressor top temp. protector cut off, and will restart after the
compressor top temp. protector restart.
8.3.3 Temperature protection of compressor discharge
When the compressor discharge temp. is getting higher, the running frequency will be limited as below rules:
---Compressor discharge temp. T5>115℃ for 5s, compressor stops and restarts up till T5<90℃
---110<T5<115℃, decrease the frequency to the lower level every 2 minutes.
---105<T5<110℃, keep running at the current frequency.
----T5<105℃, no limit for frequency.
8.3.4 Fan Speed is out of control
When Indoor Fan Speed keeps too low (300RPM) for certain time, the unit will stop and the LED will display
the failure
8.3.5 Inverter module protection
The Inverter module has a protection function about current, voltage and temperature. If these protections
happen, the corresponding code will display on indoor unit and the unit will stop working.
8.3.6 Indoor fan delayed open function
When the unit starts up, the louver will be active immediately and the indoor fan will open 10s later.
If the unit runs in heating mode, the indoor fan will be also controlled by anti-cold wind function.
8.3.7 Compressor preheating functions

Preheating permitting condition:

If T4(outdoor ambient temperature)＜3℃ and the machine connects to power supply newly or if T4＜3℃ and
compressor has stopped for over 3 hours, the compressor heating cable will work.

Preheating mode:

A weak current flow through the coil of compressor from the wiring terminal of the compressor, then the
compressor is heated without operation.

Preheating release condition:

If T4＞5℃ or the compressor starts running, the preheating function will stop.
8.3.8 Sensor protection at open circuit and breaking disconnection.
When there's one temperature sensor in malfunction, the air conditioner will display error code and will not stop
immediately, to avoid the case that the air conditioner is in urgent need.
For KFU-09HRDN1-QRC8GW,
st
time start-up and 3 minutes delay for others.
KFU-12HRDN1-QRC8GW,
33
KFU-18HRFN1-QRC8GW,