Control Mode - Pioneer YH024GHFI18RT2 Technical & Service Manual

12. CONTROL MODE

12. Control mode
Control function
1. Cooling Anti-Freeze Protection
The outdoor pressure sensor functions as real time temperature detector of evaporator. It
prevents the indoor unit evaporator temperature becoming too low. If the indoor coil temperature
is too low, the compressor will automatically start protection mode.
2. Overload Protection
To prevent system overload caused by excessive pressure, the machine will implement real-time
detection when outdoor coil temperature is too high during cooling mode or indoor coil
temperature is too high during heating mode.
3. Exhaust temperature protection
To prevent deterioration due to high exhaust temperature of compressor, the machine will realize
the real-time detection of the exhaust gas temperature. If the temperature is too high compressor
provides automatic protection.
4. Oil-return Control
When the compressor runs at low frequencies for a long time, control system will start the oil-return
mechanism. The oil in the system returns to the compressor.
5. Operation Mode
Air conditioning mode is the operation mode set by users through thermostat, two modes are
available: cooling, heating.
6. Four-way Valve Control
Four-way valve of the outdoor unit shuts down when cooling and defrosting but starts when
heating. During the heating process, the four-way valve stops working for a period of time after the
compressor is disconnected.
7. Start-up Protection
To prevent compressor from restarting frequently when the system pressure has not been
completely balanced, it cannot be restarted within 3 minutes.
8. Pressure Protection
When the pressure increases to a preset value, the pressure switch will automatically come
to protection mode. The compressor will stop and report the fault code protection.
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