What are some air conditioning repair tips?
1. Check the refrigerant. When an air conditioner fails to cool, it is usually due to a lack of refrigerant in the air conditioner or the air conditioner not being cleaned for a long time, resulting in reduced heat dissipation efficiency of the air conditioner radiator. At this point, we can first check if the refrigerant in the air conditioner is insufficient, possibly due to long-term use or refrigerant leakage. If the air conditioner is not cooling because it has not been cleaned for a long time, it should be thoroughly cleaned to ensure proper heat dissipation.
2. Condenser Dripping. When an air conditioner experiences condenser dripping, it is typically due to incorrect installation, not being level, or the air conditioner's indoor unit dripping because of a clogged drain pipe, which is a common cause of condenser dripping. When we encounter condenser dripping in the air conditioner, we can first conduct tests from these aspects.
3. Excessive Noise. The noise is too loud during the operation of the air conditioner. Check if the fan blades of the outdoor unit are deformed or if there is excessive dust accumulation, which can cause the air conditioner to produce excessive noise during operation, or if the fins are blocked. Improper placement of the air conditioner compressor and overworking are also common reasons for loud noise during air conditioner operation. We can address these aspects to simultaneously resolve the noise produced by the air conditioner.
What are common issues with air conditioner repairs?
1. Non-Cooling
Reason Analysis: Upon startup, the air conditioner's refrigeration function was normal upon initial inspection. Approximately 25 minutes later, the air conditioner pressure dropped. When the current decreased, the user reported that the compressor had been replaced, thereby eliminating any inherent compressor fault. Since the refrigeration was mostly normal within the first 25 minutes after startup, the preliminary analysis suggests a system dirt blockage or ice blockage. Upon opening the top panel of the outdoor unit, frost was observed at the capillary tube outlet. After using a lighter to melt the frost, the pressure and current returned to normal, indicating a system ice blockage. After replacing the compressor, it rained, and water entered the system.
Solution: Recycle the refrigerant back into the outdoor unit, install a desiccant filter on the low-pressure pipe of the outdoor unit, and then re-evacuate and start until the ice blockage is completely removed. Remove the desiccant filter and the refrigeration effect starts normally.
Summary of Experience: When repairing the system, technicians should avoid water from entering it, as this can lead to ice blockages. To determine if it's an ice blockage or a debris blockage, observe the capillary tube on the external machine. If frost forms at the intake of the capillary tube, it is a debris blockage. If it starts at the outlet, it is an ice blockage.
2. Poor refrigeration performance
Reason Analysis: On-site startup inspection shows the machine operates normally. Checked the indoor unit air filter and heat exchanger. The outdoor unit heat exchanger is relatively clean and will not affect the refrigeration effect. Inspected the indoor and outdoor fan motor capacitors and various participants.
3. Power failure upon startup
Analysis of the Cause: The machine tripped as soon as it was turned on. The internal machine operated normally when tested individually, indicating the fault was with the outdoor unit. Upon opening the casing, the resistance at both ends of the power line L.N was found to be ∞, confirming there was no short circuit or leakage between the two lines. Subsequently, each component of the outdoor unit was inspected, and during the examination of the compressor capacitor, a short circuit was discovered in the capacitor.
Solution: Replaced the compressor capacitor, trial operation runs smoothly.
Experience Summary: The air conditioner compressor trips as it starts up. First, check for a short circuit in the L and N power lines, then confirm whether the issue is indoors or outdoors, and continue to inspect internally for any external short circuit phenomena.
4. Frequent downtime, poor performance
Reason Analysis: The air conditioner has been installed for over a year in a restaurant with a 220V power supply. The user reported that the air conditioner failed to operate normally after a certain period of use, with a pressure of 5Kg and a current of 12.5A. There is a suspicion of a dirty condenser, and the fault of not excluding cleaning the condenser is considered. Observations of the outdoor unit revealed a slow fan motor speed, with the fan stopping for 30 minutes. The compressor's current increased and then stopped. Inspection found an open circuit in the fan motor winding, with the motor housing very hot. After measuring the winding resistance as normal, the motor cooled down, and it was determined that the fan motor capacitor was faulty.
Solution: Replaced the fan and capacitor, trial operation runs smoothly.
Experience Summary: The investigation revealed that a fan capacitor failure led to fan protection, causing inadequate system cooling and the press to stop. The press restarted after three minutes, repeating the cycle and resulting in frequent startups and shutdowns. Some faults were visible, indicating interactions between electrical control and the system. Therefore, careful inspections during maintenance are crucial to avoid detours.
5. No response upon power-on
Reason Analysis: According to the fault analysis, the power supply was first checked, with a 220V input, ruling out power supply issues. The resistance of the L.N plug was found to be infinite, suggesting a blown fuse or a damaged transformer. Upon opening the indoor unit panel and inspecting the mainboard, the fuse was found to be intact. During transformer testing, a primary circuit break was discovered.
Solution: Transformer replaced, trial operation runs smoothly, fault resolved.
Experience Summary: During the repair process, if the entire unit does not respond, start with the power circuit first to quickly and accurately identify the fault.
6. Non-Heating
Analysis of the Cause: Upon initiating heating, the external fan rotates, but the compressor does not. The four-way valve is closed. Measurement of the internal four-way valve relay output indicates normal. The AC contactor power is also normal. Upon forcibly pressing the AC contactor, the compressor starts, after which the measurement shows the AC contactor coil has been disconnected.
Solution: Replacing the contactor and testing showed normal operation.
Experience Summary: If the internal machine power supply is normal, the external fan power supply is normal, the four-way valve is properly drawing, and the compressor is not operating, first check if the contactor is drawing properly and if the coil resistance value is normal. Then, inspect the compressor issue. Typically, damaged AC contactors are due to coil burning, loose contacts, dirt, or burning.
7. Test Run Fails to Cool
Analysis of the Cause: The machine was powered on, internal components operated normally. Observing the external machine, a "humming" sound was heard during the compressor startup, but it failed to start properly. Voltage was measured dropping from 230 volts to 138 volts, indicating a compressor protection. It was determined that there was an issue with the power supply. Upon inspecting the user's power outlet, it was found that the electrician had mistakenly used a grounding wire as the neutral line. After the correction, the trial operation ran normally.
Solution: Ground and Neutral Connection
Experience Summary: It is mandatory to use the N-end neutral wire during installation; the grounding wire cannot be replaced. Reversing the grounding and neutral wires may also cause the circuit breaker to trip. New installation issues should focus on checking the power source, as sometimes the power cables are too thin, resulting in a large starting current for air conditioners, which can also lead to difficulty in starting due to conductor voltage drop. Besides power cable issues, the size of the circuit breaker is often the cause of starting trips.
