Main Protection - Carrier QHC Series Service Manual

In one second interval.
NOTE:
A guide on using the infrared remote is not included in this literature package.

9.3 Main Protection

9.3.1 Three minutes delay at restart for compressor
st
Less than 1 minute delay for the 1 time start-up and 3 minutes delay for others.
9.3.2 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.
9.3.3 Temperature protection of compressor discharge
Compressor discharge temp. T5>108℃ for 9s, compressor stops.
9.3.4 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
9.3.5 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.
9.3.6 Indoor fan delayed open function
When the unit starts up, the louver will be active immediately and the indoor fan will open 7s later.
If the unit runs in heating mode, the indoor fan will be also controlled by anti-cold wind function.
9.3.7 Compressor preheating functions
Preheating permitting condition:
When T4(outdoor ambient temperature)＜3° C, the preheating function will be activated.
9.3.8 Sensor protection at open circuit and breaking disconnection.
When there's only one temperature sensor in malfunction , the air conditioner will keep working but
show the error code, in case of any emergency use.
When there's more than one temperature sensor in malfunction, the air conditioner will stop working
9.3.9 Refrigerant leakage detection
This function is only active in cooling mode. It can better prevent the compressor being damaged by
refrigerant leakage or compressor overload.
Open condition:
When compressor is active, the value of the Coil temperature of evaporator T2 has no change or very
little change.
25