20 common after-sale faults and treatment methods for air source heat pump heating systems

In recent years, air source heat pump heating projects have blossomed everywhere in the north, and their application fields have become more and more extensive. However, because heat pump heating has been promoted in northern China not long ago, engineering companies also lack sufficient technology and experience for such projects, so that when problems arise, many people will be at a loss. So when the air source heat pump heating system fails, what should we do? Based on the collection of online materials, Leomon edits and organizes for everyone to learn from.

1) Phase sequence failure

The cause of the failure: the power provided by the air source heat pump host does not match the host. If the compressor is connected reversely, it is easy to be burned out, so it is necessary to install a phase sequence protector. How to judge the situation? Under normal circumstances, the fault code "LELL3" will be displayed directly on the display panel.

Solution:

First check whether the wiring of the power supply voltage line is correct; if the problem is not solved, it may be that the phase sequence board is broken, just replace the phase sequence board.
According to experience, most of the wires are reversed, and the phase sequence board hardware problems are rare, because the new machines that leave the factory are generally strictly tested.

2) Failure of water flow switch

The cause of the failure: The water flow is too small to close the water flow switch, which causes the air source heat pump to fail to start.

Solution:

If a failure occurs after a period of operation, first check and clean the pipeline filter (the newly installed air source heat pump does not need to be checked);
Check whether the pipeline valve is damaged or opened;
Check whether the circulating pump meets the flow requirements of the unit;
Whether the water pump is connected reversely during the commissioning of the new air source heat pump;
If everything is normal, then the water flow switch itself is faulty, and you need to replace it, or short-circuit the two wires of the water flow switch on the main board. If it starts, it must be the water flow switch problem.

3) Failure of water inlet sensor

The cause of the failure: also called the return water sensor failure, the main board cannot detect the water inlet temperature or the detected value exceeds the limit value.

Solution:

If the wire is not connected properly, you need to check whether the probe circuit is damaged, and check whether the connector on the main board side is firm;
The sensor failure itself has a problem, replace the water inlet temperature probe;
If the main board is broken, the water temperature will not be detected. Replace the main board at this time.

4) Failure of high voltage switch

The cause of the failure: the high-pressure measurement pressure of the air source heat pump unit is too high and exceeds the design value, the pressure gauge exceeds the yellow line, and immediately reaches the red line, a high-pressure failure will occur.

Solution:

Consider the lack of water flow, check and clean the pipeline filter;
Check whether the pipeline valve is damaged or opened. Valves with poor quality may not open properly, resulting in insufficient water flow, and high pressure alarms will occur if the heat of the machine cannot be exchanged;
Check whether the circulating pump meets the flow requirements of the unit and whether it is operating normally;
Check whether there is scale inside the water inlet and outlet of the machine. If there is scale, the heat generated by the compressor cannot be exchanged, and it is easy to cause high pressure failure.

5) Low-voltage switch failure

Cause of failure: This failure is relatively common, that is, the low pressure pressure is too low, at this time the low pressure switch will be disconnected.

Solution:

Check whether the unit is lacking in fluorine. When encountering this kind of failure, the first consideration is the lack of fluorine and fluorine leakage, because the damage of electronic expansion valve and other components or the vibration of the equipment causes it to crack, and the poor welding process of copper pipes will cause fluorine leakage. Low pressure alarm;
Check whether the fins of the surface cooler are blocked. If the fins are dirty, or the surface of the evaporator is seriously blocked, it is easy to cause low pressure failure. Then beware of the attachment of catkins in the north;
Check whether the fan is operating normally. If the fan is not operating normally, frost is likely to occur, especially in winter, which may cause low-voltage switch failure.

The picture below is because it has not been cleaned for a long time, 1/3 of the entire evaporator is stuck, so low pressure failure is prone to occur.

6) The outlet water temperature is too high

The cause of the failure: the outlet water temperature exceeds the set value, which occasionally happens.

Solution:

Check the probe and its related parts;
Check whether the outlet water temperature value is consistent with the actual value, check whether the water tank temperature value is equal to the actual value, you can directly touch it with your hand, if the temperature is consistent, then the probe is broken and the probe is replaced;
Check and clean the pipeline filter;
Check whether the pipeline valve is damaged or not;
If the valve is not damaged and opened, check whether the circulating pump meets the flow requirements of the unit and whether it is operating normally;
If all the above are normal, you need to check the motherboard to see if there is any problem with the air source heat pump motherboard.

7) Communication failure

The cause of the failure: the air source heat pump display board cannot receive the data from the main board.

Solution:

As far as the normal installation method is concerned, the controller installation will be moved to the house or a place that is convenient for observation, and the cable needs to be extended, so you need to check whether the extension cable is damaged;
Check whether the display signal cable connector is firmly connected;
Check whether the wiring on the back of the monitor is loose or not, and see whether the four wires in the figure below are loose;
Check the display board for problems. Generally speaking, the display board has two signal wires and two power wires. If the distance between the wires is very long, the controller does not supply enough power, and the display board is prone to flashes, then you can Add a transformer to the location to ensure power supply, and the display will be normal.

8) Coil sensor failure

The cause of the failure: the main board cannot detect the coil temperature or the detected value exceeds the limit value. If the coil is faulty, it will cause inaccurate defrosting, which will have a great impact on defrosting in winter.

Solution:

Check whether the probe circuit is damaged;
Replace the coil temperature probe, and check whether the connector of the probe on the main board side is firm;
The sensor itself is not faulty, and the wiring is not loose. Then there is a problem with the motherboard, just replace the motherboard.

9) Failure of exhaust sensor

The cause of the fault: the mainboard cannot detect the exhaust temperature or the detected value exceeds the limit value, or the exhaust temperature detected when the unit is in working condition is lower than 10℃. This kind of failure generally rarely occurs. In winter, if there is fluorine leakage or various reasons make the system have problems and the machine does not work, and the ambient temperature is lower than 10°C, then the exhaust sensor failure will be reported.

Solution:

Check whether the connector of the probe on the main board side is firm;
Inquire whether the exhaust temperature value is consistent with the actual temperature, if not, check whether the probe circuit is damaged, and replace the coil temperature probe;
If it is consistent with the actual temperature, check whether the compressor is working normally when the unit is working;
Check the motherboard for problems.

10) Antifreeze protection

The cause of the failure: the ambient temperature is lower than the antifreeze setting value, and the antifreeze cycle is started to prevent the equipment from being damaged by freezing. In winter, when a single air source heat pump machine stops working, anti-freezing is very important. It must be activated when the temperature is 3°C lower than the ambient temperature, otherwise it may freeze the pump, pipes, and machines. . If the water pump freezes, the antifreeze protection has not been activated yet, and the water pump is easy to burn out, so the antifreeze protection is very important for the stand-alone installation.

Solution:

Check whether the ambient temperature value is consistent with the actual value. If it is consistent, it is normal. If it does not, the probe needs to be replaced.

11) Exhaust temperature is too high

The cause of the failure: the exhaust temperature detected by the air source heat pump host is greater than the limit value (125°C).

Solution:

Check whether the exhaust temperature value is consistent with the actual temperature, if not, replace the coil temperature probe;
If it is consistent with the actual temperature, check the operation of the unit, check whether the fins of the meter cooler are blocked, check whether the unit is lack of fluorine, whether the four-way valve is ventilated, whether the compressor is ventilating, and whether the refrigerant pipeline is blocked.

12) The outlet water temperature is too low

Cause of failure: The main board of the air source heat pump detects that the water temperature is lower than the limit value (3°C), which will cause the pump head flow to be insufficient.

Solution:

Query whether the outlet water temperature value is consistent with the actual temperature, if not, replace the outlet water temperature probe;
If it is consistent with the actual temperature, check whether the water tank temperature value is consistent with the actual value (if the water tank temperature control machine is working), check and clean the pipeline filter, check whether the pipeline valve is damaged or not, and check whether the circulating pump meets the unit flow Requirements, whether it is operating normally.

13) High temperature protection

The cause of the failure: the detected water temperature of the air source heat pump system exceeds the upper limit of temperature control (60°C).

Solution:

Check whether the water tank temperature value is consistent with the actual value (if the water tank temperature control machine is working), if the actual temperature exceeds the temperature control upper limit, check whether other heat sources are turned on normally, if it is normal, the fault will automatically recover when the temperature drops. If the check value does not match the actual value, replace the temperature control probe.

Generally speaking, in practical applications, solar energy is combined with air energy. In summer, when the temperature of solar water heating exceeds the set upper limit, high temperature protection will appear. When the temperature is lower than this set value, it will automatically be eliminated. Worry about the alarm of high temperature protection.

Failure and handling without failure code

14) The heating capacity of the unit is reduced

The cause of the fault: the heat absorbed by the air source heat pump unit is reduced, the heat exchange efficiency is reduced, and the heat loss of the system is serious.

Solution:

Check whether the fins of the surface cooler of the unit are dirty and blocked;
Check whether the exhaust air of the unit is not smooth, such as the fan does not rotate, the fan blade is damaged, the location of the unit is not well ventilated, etc.;
Check whether the water side heat exchanger is scaled, whether the water pump is aging, and whether the water flow is reduced;
Poor heat preservation of pipes, aging of heat preservation pipes or long pipes will reduce the heat preservation effect.

15) The compressor does not work

Cause of failure: All air source heat pumps are normal (the display does not indicate a compressor failure). Then the possible causes of failure are the following five points: power failure, compressor contactor damage, compressor protector disconnection, compressor wiring loose, and compressor overheat protection during long-term high-load operation.

Solution:

Check whether the power supply voltage is normal, check the AC contactor, protector and wiring;
Check whether the motor part of the compressor is very hot. If it is overheated, it means that the compressor has been working too long and the load is too large. You need to cool down and check the cause.

16) The compressor is noisy

Causes of failure: The main reasons for this part are: the compressor only compresses gas but not liquid, and liquid refrigerant enters the compressor; internal parts of the compressor are damaged; the compressor has insufficient refrigerating oil or poor oil return (the gas-liquid separator has a problem, divided The liquid is not thorough).

Solution:

Check whether the expansion valve is malfunctioning;
Replace the compressor;
Add appropriate amount of refrigerating oil to make the compressor lubrication effect better;
Check whether the refrigerant system is blocked.

17) The fan does not turn

Cause of failure: No start signal, possibly broken capacitor or blown out fan.

Solution:

Check whether the start signal of the fan on the main board of the air source heat pump is normal and whether there is output;
Whether the AC contactor is in good condition;
Check whether the capacitor is loose or not, and replace the capacitor;
Replace the motor.

18) The compressor is running but the unit is not heating (cooling)

Cause of failure: This failure is more difficult to occur, unless all failures of low voltage and high voltage have failed. The main reasons are refrigerant leakage, refrigerant system blockage, and compressor failure.

Solution:

Leak detection and filling of refrigerant;
Detect blocked parts;
Replace the compressor.

19) Exhaust pressure is too high (high pressure gauge)

Causes of failure: The main reasons are insufficient water flow, scale formation on the heat exchanger, too much refrigerant, and air in the refrigerant system.

Solution:

Check and clean the air source heat pump pipeline filter, check whether the pipeline valve is damaged or open, and check whether the circulating pump meets the flow requirements of the unit and operates normally;
Clean the scale;
Let go of the excess refrigerant;
Drain the refrigerant, re-vacuum and add refrigerant.

20) Low suction pressure (low pressure gauge)

Cause of failure: The main reason is that the surface cooler fins are dirty, the fan exhaust is not smooth, the refrigerant is small and leaking, the refrigerant system is blocked or the expansion valve is small.

Solution:

Clean the surface cooler;
Repair the fan and remove obstacles;
Leak detection, leak repair and refrigerant;
Check the clogged accessories and replace, adjust the expansion valve.

Exhaust pressure is too high or suction pressure is too low to rely on air source heat pump engineers and maintenance personnel to find out in advance. When the high pressure and low pressure alarms are not yet there, there will be some precursors for observation, such as insufficient water flow, Heat exchanger scales, etc., through advance judgment to deal with the high pressure and low pressure conditions in advance.