Heat Pump Common Faults With Fault Codes And Solution (1)

Heat Pump Common faults with fault codes and their handling : 1) Phase sequence fault. 2) The water flow switch is faulty. 3) The water inlet sensor is faulty. 4) High voltage switch malfunction. 5) Low voltage switch malfunction. 6) The outlet water temperature is too high. 7) Communication failure. 8) The coil sensor is faulty. 9) Exhaust sensor malfunction. 10) Freeze protection. 11) The exhaust temperature is too high. 12) The outlet water temperature is too low. 13) High temperature protection. 14) The heating capacity of the unit has decreased. 15) The compressor is not running. 16) The compressor has high noise during operation. 17) The fan does not turn. 18) The compressor is running but the unit is not heating (cooling). 19) The exhaust pressure is too high (high-pressure gauge). 20) Low suction pressure (low pressure gauge)

In recent years, air source heat pump heating projects have blossomed throughout the northern region, and their application fields have become increasingly widespread. However, due to the recent promotion of heat pump heating in the north, engineering companies also lack sufficient technology and experience in such projects, so that when problems arise, many people will be helpless.

Common faults with fault codes and their handling

1) Phase sequence fault

Fault reason: The power supply provided by the host does not match the host. If the compressor is connected in reverse, it is easy to burn out, so a phase sequence protector needs to be installed. How to judge the situation? Under normal circumstances, the fault code "LELL3" will be displayed directly on the display board.

Handling method:

Firstly, check if the power supply voltage line wiring is correct;

If the problem has not been resolved, it may be that the phase sequence board is broken. Just replace the phase sequence board.

According to experience, most of the wiring is reversed, and it is rare for the hardware of the phase sequence board to have problems, as new machines from the factory are generally strictly tested.

2) Water flow switch failure

Fault cause: The low water flow cannot close the water flow switch, resulting in the inability to start the machine.

Handling method:

If there is a malfunction after running for a period of time, first check and clean the pipeline filter (new machines do not need to be inspected);

Check if the pipeline valves are damaged or open;

Check whether the circulating pump meets the flow requirements of the unit;

Is the water pump connected backwards during the debugging of the new machine;

If everything is normal, then the water flow switch itself is malfunctioning and needs to be replaced, or the two wires of the water flow switch on the motherboard should be directly shorted. If it starts, it must be a problem with the water flow switch.

3) Water inlet sensor failure

Reason for fault: Also known as a return water sensor fault, the motherboard cannot detect the inlet water temperature or the detected value exceeds the limit value.

Handling method:

The wire is not properly connected, it is necessary to check the probe circuit for damage and whether the connector on the motherboard side is secure;

There is a problem with the sensor itself, replace the inlet temperature probe;

If the motherboard is broken, the water temperature will not be detected, so replace the motherboard.

4) High voltage switch failure

Fault cause: The high pressure measurement pressure of the unit exceeds the design value, and the pressure gauge exceeds the yellow line. If it reaches the red line immediately, a high pressure fault will occur.

Handling method:

Considering insufficient water flow, check and clean the pipeline filter;

Check if the pipeline valves are damaged or open. Poor quality valves may not open properly, resulting in insufficient water flow and the inability of the machine to exchange heat, leading to a high-pressure alarm;

Check whether the circulating pump meets the flow requirements of the unit and operates normally;

Check if there is scale inside the inlet and outlet of the machine. If there is scale, the compressor will not be able to generate heat and it is also prone to high-pressure faults.

The following picture shows a 5P machine with a high amount of scale inside the heat exchanger. In this case, it can be cleaned with about 15% phosphoric acid for about 15-20 minutes. The cleaning time is shorter for simple structures and longer for complex structures.

5) Low voltage switch failure

Fault cause: This fault is quite common, which is that the low-pressure pressure is too low, and at this point, the low-pressure switch will open.

Handling method:

Check if the unit is short of fluorine. When encountering such a fault, the first consideration is the lack of fluorine and leakage. Damage to electronic expansion valves and other components, vibration of equipment causing them to crack, and poor welding process of copper pipes can lead to fluorine leakage and low pressure alarm;

Check if the fins of the surface cooler are blocked. If the fins are dirty or the surface of the evaporator is severely blocked, it is easy to cause low-pressure faults. Therefore, in the north, it is necessary to be careful to prevent the attachment of willow catkins;

Check if the fan is operating normally. If the fan is not operating properly, it can easily cause frost, especially in winter, which can lead to low-voltage switch failure.

The following figure shows that due to a long time of not cleaning, one-third of the entire evaporator has become stuck, which can easily lead to low-pressure faults.

6) Excessive outlet temperature

Fault cause: The outlet water temperature exceeds the set value, which occasionally occurs.

Handling method:

Check the probe and its related components;

Check if the outlet temperature value matches the actual value, and check if the temperature value of the water tank is equal to the actual value. You can directly touch it with your hand. If the temperature matches, it means that the probe is broken and you can replace it;

Check and clean the pipeline filter;

Check if the pipeline valve is damaged and open;

If the valve is not damaged and opened, it is necessary to check whether the circulating pump meets the unit flow requirements and operates normally;

If all of the above are normal, you need to check the motherboard to see if there are any issues.

7) Communication failure

Fault reason: The display board cannot receive data from the motherboard.

Handling method:

If the controller is installed in a normal way, it will be moved to a place inside the house or convenient for observation. Therefore, it is necessary to extend the cable and check if the extension cable is damaged;

Check if the signal cable connector of the monitor is securely connected;

Check whether the wiring on the back of the monitor is loose or not, and see if these four wires are loose in the following figure;

Check the display board for any issues. Generally speaking, a display board has two signal lines and two power lines. If the distance between the lines is too long, the controller may not have enough power and the display board may experience flickering. Therefore, a transformer can be added at the controller position to ensure power supply, and the display will be normal.

8) Coil sensor failure

Fault reason: The motherboard cannot detect the coil temperature or the detected value exceeds the limit value. If there is a malfunction in the coil, it will cause inaccurate defrosting, which can have a significant impact on winter defrosting.

Handling method:

Check if the probe circuit is damaged;

Replace the coil temperature probe and check if the connector of the probe on the motherboard side is secure;

If the sensor itself is not faulty and the wiring is not loose, then there is a problem with the motherboard. Simply replace the motherboard.

9) Exhaust sensor malfunction

Fault reason: The motherboard cannot detect the exhaust temperature or the detected value exceeds the limit value, or the exhaust temperature detected when the unit is in operation is below 10 ℃. This type of malfunction is generally rare. In winter, if there is a fluorine leakage or various reasons that cause the system to malfunction, the machine will not work, and the ambient temperature is below 10 ℃, then an exhaust sensor malfunction will be reported.

Handling method:

Check if the connector of the probe on the motherboard side is secure;

Check if the exhaust temperature value matches the actual temperature. If it does not match, check the probe circuit for damage and replace the coil temperature probe;

If it matches the actual temperature, check whether the compressor is working properly while the unit is operating;

Check for any issues with the motherboard.

10) Antifreeze protection

Fault cause: The ambient temperature is lower than the antifreeze setting value, and the antifreeze cycle is started to prevent equipment damage caused by freezing. When a single machine stops working in winter, antifreeze is crucial. It is important to activate antifreeze protection when it is 3 ℃ below the ambient temperature, otherwise it may cause damage to the water pump, pipeline, and machine. If the water pump freezes and the antifreeze protection is not yet activated, the water pump is easily burned out, so antifreeze protection is crucial for single machine installation.

Handling method:

Check if the ambient temperature value matches the actual value. If it matches, it is normal. If it does not match, the probe needs to be replaced.