Actuation of High Pressure Switch
1. Error Detection Method
It is judged an error if the internal circuit of the high pressure switch is dead.
The electronic circuitry of the high pressure switch is cut off if the pressure at the pressure sensor port of the high pressure switch reaches 3.80 MPa. Once it is cut off, it remains cut off until the pressure drops to 3.15 MPa.
- The high pressure switch is malfunctioning.
- Service valve inside the outdoor unit closed
- There is a short air circuit through the outdoor unit’s heat exchanger. (when cooling)
- The outdoor unit’s fan is broken. (when cooling)
- The outdoor unit’s heat exchanger is clogged. (when cooling)
- There is a short air circuit at the indoor unit. (when heating)
- The filter of the indoor unit is clogged. (when heating)
- The fan of the indoor unit is broken or the fan motor is malfunctioning. (when heating)
- The refrigerant circuit is closed and the high pressure is increasing abnormally high. (solenoid valve or expansion valve not activated, a stuck check valve, etc.)
- Refrigerant overcharged.
- Nitrogen or air contaminated in the refrigerant system
2. Error Diagnosis
High pressure switch
|1-1||The socket of the high pressure switch is securely inserted in the PC board. The wiring is not opened.||Yes||1-2|
|No||Correct connection and/or wiring|
|1-2||Even if parts near the high pressure switch are shaken quite a lot, the high pressure cutoff will be activated.
Even if the covering is in good condition, in several cases vibration has caused wiring inside to open.
|Yes||Replace the high pressure switch (wiring)|
|Service valve inside the outdoor unit closed||Yes||Open the service valve|
|There is an extreme difference in temperature in/out of the service valve.||Yes||2-3|
|Check the flare connection, someone may have forgotten to remove the bonnet. If there is a problem within the service valve, replace the valve.|
Problem around the heat exchanger
|3-1||While cooling is operating an alarm is occurred.||Yes||3-2|
|The intake temperature (ambient temperature) of the outdoor unit’s heat exchanger is above 46°C.||Yes||Prevent air short circuit|
|3-3||The outdoor unit’s heat exchanger is clogged.||Yes||Clean the heat exchanger|
|3-4||Check whether the outdoor unit fan is normal or if the sockets are firmly pressed onto the plugs on the outdoor PC board, as well as if any wiring is opened. Are these checking finished without fail?||Yes||4-1|
|No||Replace the outdoor unit fan. Correct connection and/or wiring|
|3-5||While heating is operating an alarm is occurred.||Yes||3-6|
|3-6||The intake temperature (ambient temperature) of the indoor unit is above 36°C.||Yes||Prevent air short circuit|
The filter of the indoor unit is clogged.
|Yes||Clean the filter|
The fan of the indoor unit is broken or the fan motor is faulty.
|Yes||Replace the indoor fan (motor)|
Blockage in the refrigerant circuit
Is the outdoor unit’s electronic control valve operating correctly? (Check for debris clogging the electronic control valve, a problem with the electronical coil and/or the control PC board.)
|No||Repair the electronic control valve of the outdoor unit|
The indoor unit's expansion valve is operating correctly. (check for debris clogging the valve, a problem with the electronical coil and/or the control PC board)
|No||Repair the expansion valve of the indoor unit|
|4-3||If an alarm is occurred with the high pressure below 3.80 MPa, with the pressure measured as displayed by the manifold gauge, check the check valve in the compressor discharge line. Are these checking finished without fail?||
|No||Replace the check valve in the compressor discharge line|
|4-4||The electronic control valve is faulty. In systems where the solenoid valve kits and the ice thermal storage tank are connected, check these solenoid valves.||Yes||Replace the electronic control valve and/or solenoid valve.|
|5-1||Error occurs when the system is operating in cooling mode.||Yes||5-3|
|5-2||Error occurs when the system is operating in heating mode.||Yes||5-4|
|5-3||An alarm is occurred with the high pressure at 3.80 MPa, with the pressure measured either as displayed by the monitoring software or with a manifold gauge, at which time the temperature of liquid in the outdoor unit’s heat exchanger is detected to be at the temperature of the outside air.||Yes||5-5|
|No||Contact the service representative|
|5-4||An alarm is occurred with the high pressure at 3.80 MPa, with the pressure measured either as displayed by the monitoring software or with a manifold gauge, at which time the temperature of liquid in the indoor heat exchanger is detected to be at room temperature (intake temperature).||Yes||5-5|
|No||Contact the service representative|
|5-5||The system may be overcharged. Check how much refrigerant was added during installation. When a system is inspected for airtightness, it is seldom that enough nitrogen has been expelled, so some remains in the circuit. In this case, it is necessary to collect the refrigerant and then recharge the system.|