Heat Pump Common Faults With Fault Codes And Solution (2)

11) Exhaust temperature too high

Fault cause: The exhaust temperature detected by the host is greater than the limit value (125 ℃).

Handling method:

Check if the exhaust temperature value matches the actual temperature, and if it does not match, replace the coil temperature probe;

If it matches the actual temperature, check the operation of the unit, check if the fins of the surface cooler are blocked, check if the unit is short of fluorine, if the four-way valve is in gas, if the compressor is in gas, and if the refrigerant pipeline is blocked.

12) Outlet water temperature too low

Fault cause: The motherboard detects that the water outlet temperature is below the limit value (3 ℃), which will cause insufficient water pump head flow.

Handling method:

Check if the outlet temperature value matches the actual temperature, and if it does not match, replace the outlet temperature probe;

If it matches the actual temperature, check whether the temperature value of the water tank matches 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, check whether the circulating pump meets the unit flow requirements, and whether it operates normally.

13) High temperature protection

Fault reason: The system detects that the water temperature exceeds the upper limit of temperature control (60 ℃).

Handling method:

Check whether the temperature value of the water tank matches the actual value (if the water tank temperature control machine is working). If the actual temperature exceeds the upper limit of the temperature control, 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.

In general, in practical applications, solar energy and air can be combined more frequently. In summer, when the temperature of solar water exceeds the set upper limit, high temperature protection occurs. When the temperature drops below this set value, it will automatically eliminate it. Don't worry about the alarm of high temperature protection.

Fault and handling without fault codes

14) Reduced heating capacity of the unit

Reason for fault: The unit absorbs less heat, reduces heat exchange efficiency, and causes severe heat loss in the system.

Handling method:

Check if the fins of the unit surface cooler are dirty and blocked;

Check if the unit has poor ventilation, such as the fan not rotating, damaged blades, and poor ventilation in the unit's location;

Check for scale formation in the water side heat exchanger, aging of the water pump, and reduced water flow rate;

Poor insulation of pipelines, aging of insulation pipes, or long pipelines can all reduce the insulation effect.

15) Compressor not running

Fault cause: All are normal (the display does not indicate compressor failure). So there are five possible causes of faults: power failure, damaged compressor contactor, disconnected compressor protector, loose compressor wiring, and overheating protection during prolonged high load operation of the compressor.

Handling method:

Check if the power supply voltage is normal, check the AC contactor, protector, and wiring;

Check if the motor part of the compressor is very hot. If it overheats, it means the compressor is working too long and the load is too high. It is necessary to cool down and check the cause.

16) High noise during compressor operation

Fault cause: The main reason for this part is that the compressor only compresses gas but not liquid, and liquid refrigerant enters the compressor; Damaged internal parts of the compressor; Insufficient refrigerant oil or poor return oil in the compressor (there is a problem with the gas-liquid separator, and the liquid is not completely separated).

Handling method:

Check if the expansion valve is malfunctioning;

Replace the compressor;

Add an appropriate amount of refrigerant oil to improve the lubrication effect of the compressor;

Check if there are any blockages in the refrigerant system.

17) Fan does not rotate

Fault cause: No start signal, possibility of capacitor damage or fan burnout.

Handling method:

Check if the startup signal of the motherboard fan is normal and if there is an output;

Whether the AC contactor is intact;

Check if the capacitor is loose or if the capacitor drum is missing and replace it;

Replace the motor.

This is the motherboard shown in the above figure. Each electrical component, including the water pump, fan, compressor, electronic expansion valve, and other parts, is displayed. If the light is on, it indicates that it is working. The bottom two are fuses. If there is a problem with the fan, the fuse will burn out.

18) Compressor running but unit not heating (cooling)

Reason for fault: This fault is relatively difficult to occur unless all low and high voltage faults in the "Heat Pump Market Watermark" fail. The main reasons are refrigerant leakage, refrigerant system blockage, and compressor failure.

Handling method:

Leak detection and filling with refrigerant;

Detect blocked components;

Replace the compressor.

19) High exhaust pressure (high-pressure gauge)

Fault cause: The main reasons are insufficient water flow, scale formation in the heat exchanger, excessive refrigerant, and air in the refrigerant system.

Handling method:

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 and operates normally;

Clean scale;

Release excess refrigerant;

Release the refrigerant and vacuum again to add refrigerant.

20) Low suction pressure (low pressure gauge)

Fault cause: The main reasons are dirty fins of the surface cooler, poor fan exhaust, low and leaking refrigerant, blockage of the refrigerant system, or small opening of the expansion valve.

Handling method:

Clean the surface cooler;

Repair the fan and remove obstacles;

Leak detection, leak repair, and refrigerant addition;

Check the blocked accessories and replace them, adjust the expansion valve.

If the exhaust pressure is too high or the suction pressure is too low, it is necessary for engineering and maintenance personnel to detect it in advance. When the high and low pressure alarms are not yet reached, there will be some precursor phenomena that can be observed, such as insufficient water flow, scale formation in the heat exchanger, etc. By predicting in advance, the high and low pressure conditions can be dealt with in advance.

In the electrical diagram of a system for a heat pump heating project in a certain fire brigade in 2014, there were two high and two low pressure gauges. The low pressure gauge displayed low, and it was necessary to predict in advance before the low pressure alarm. This may be due to the dirty surface cooler, poor fan speed, small opening of the expansion valve, or slight leakage of the refrigerant enzyme. However, in order to avoid a low pressure alarm, it is necessary to predict in advance and test the system in advance.