【 Weak current College 】 McQuay air conditioning failure of judgment and solutions

I. McQuay air conditioning troubleshooting methods
Air conditioner in the refrigeration system and the electrical system components, it's running again and the working environment and conditions are closely related to the air conditioner's fault analysis needs.
Faults can be divided into two categories: one category for reasons outside the machine or human failure (especially power is normal) and the other for the tank failure. In the analysis processing failures, first of all, the reason should be excluded from outside the machine. Exclude external factors, and can be built-in fault is divided into the refrigeration system faults and electrical system failures, you should exclude the electrical systems in General. As regards the electrical system failure, also available from the following two ways to find: switching power supply for transmission; motor windings is normal.
In accordance with the above mentioned general analysis of ideas, you can narrow your scope, faults are natural to the bottom.


Second, McQuay air conditioning failure check
Refrigeration system is running, a preliminary investigation is die, see, hear, and search, ask. The approach is simple and effective.
Touch: the touch suction tube, exhaust pipes, compressor, evaporator outlet, condenser and other parts of the body temperature. Normal suction tube, exhaust heat and cold. Compressor temperature usually 90-100 ° c, the condensation pipe wall temperature of 45-55 c, evaporator tube wall water dew, outlet has air-conditioning. By feel they can judge the refrigeration effect is good or bad.
See: see capillary pressure part of frosting. Normal refrigeration, the beginning of the compressor, capillary produces thin layer of cream, then gradually melted, but insufficient or pipeline plug refrigerant will occur frosting phenomenon of not.
It is important to note that the outdoor heat exchanger in the winter by heat pump cycle mode, it is a low-voltage, low-temperature parts also occur refrigerant leaks and clogging. If the capillary export to the outdoor heat exchangers entrance this segment Frost and other parts of the dryer, which indicates that the capillary is half a block. The refrigerant from the surface, and half a block is the same.
Also be noted that the air conditioner operation, generally you should take a look at the air conditioner external working conditions, such as indoor and outdoor temperature is too high or too low, the filter is too dirty or there is no ventilation and other phenomena, in order to exclude external causes and factors such as improper installation and use.
Listen to: experienced maintenance staff to voice response is rather sensitive. When the "hum" compressor sound can be immediately identified the compressor does not start correctly, you should immediately turn off the power to find causes of downtime, when you hear a "'" this increasingly lighter air sound (the system pressure balance issue), you know the basic no clogging the system.
In addition, the hearing may determine other noise, for example: ext axial flow fans may hit iron tablets sound enclosure; the fan to the lack of oil "Squeak" scream; fan centrifugal fan and a foam cover friction "scrape" sound; compressor corners bolt, vibration of sound; sound of capillary touch shell.
Enquiries: generally available pressure gauge, thermometer, clip-on semiconductor ammeter, and so on pressure, temperature, current.
For window type air conditioner with clamp ammeter check for current, voltage, resistance is very convenient. Current readings should be around in the rated current range (with temperature and low current slightly changed). For a split air conditioner, with manifold table detection in high and low pressure is a practical, fast and effective method of judging.
When the ambient temperature is around 30 ° c (air conditioning and refrigeration mode), if low table pressure (gauge pressure) in 0.4MPa following, it indicates that insufficient or leakage of refrigerant. High pressure table pressure (gauge pressure) the normal value should be around 2MPa too high or too low is the exception. Condenser outlet to plug enables high pressure rise and low pressure drop.
Inspection and observation of General project: ⑵ low-pressure ⑴; pressure; high pressure ⑶ outage balanced pressure; ⑷ suction temperature; ⑸ exhaust pipe temperature; temperature; ⑺ ⑹ compressor, condenser, evaporator ⑻ ⑼ filters; ⑽ capillary; ⑾ operating current.

III. non-air-conditioner itself causes faults
Machine outer fault was due to a power supply, and others, are listed below:
1. power supply issues
⑴ the supply voltage must not be too low. Generally when a voltage lower than normal voltage 220V 15%, the air conditioner compressor will be difficult to start. Air conditioning operation, ensure the required voltage General 198V above.
⑵ air conditioner dedicated circuit fuse blow for small capacity, or capacity is too large and no protective effect, power outlet is bad, fuse capacity is too small, etc are not allowed.
⑶ power cable cross-sectional area can not be too small.
⑷ air conditioner room too many household appliances and power line capacity is insufficient, it is not allowed.
⑸ part of network voltage low, into electrical resistance, especially the use of air conditioning units, such as the use of high-power motors in the vicinity of electrical equipment, often resulting in excessive voltage fluctuation range.
⑹ power sector temporary power outage or momentary brake, alarm.
2. installation, the environment and use issues
⑴ air-conditioner and obstructions affecting the airflow to reduce heat efficiency, so that the cooling capacity of air conditioners.
⑵ the room temperature is too high or too low, over air conditioner use temperature range allowed.
⑶ a/c room enclosed, door and window is not closed, indoor access frequently.
⑷ indoor use heating appliances, air conditioner, direct sunlight is higher than 43 ° c ambient temperature.
⑸ condenser inlet and outlet of cooling efficiency sharp decline, causing refrigerant condensing temperature and pressure to rise, even more than the actual load of the compressor. Because the throttling state changes, and evaporation area is certain, suction temperature increase in this vicious cycle, there will be intermittent and stopping the compressor, or jitter stop phenomenon.
⑹ air conditioner room area is too large or indoor height too high, and the specifications for the cooling capacity of air conditioners is too small.
⑺ air conditioner room air pollution, dust, resulting inThe air filters with dust, dirt, indoor air circulation disruption, affecting heat.
⑻ If window type air conditioner installation position is too low or too high, do not meet the installation requirements.