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放置一个温度计，通常是数字温度计，以确保其精确性和风速，位置在前端排气口之一。这并不是一个精确的科学实验，但温度最高为10℃时为正常。排气口的温度会随着当天的温度儿变化。当天环境温度为15-20℃时，排气口温度正常值为6-8℃。如果温度高于这些示例值，那么就可以推断系统没有正常运行了。
Normal Operation Pressures 正常运行压强

Note: These readings may vary due to the ambient temperature conditions and manufacturer’s specifications. It is always wise to cross reference with the manufacturer’s technical data.
注意：这些数据由于当天的温度情况和制造商的规格会发生变化。和制造商的技术数据进行相互对照是很明智的做法。
Poor cooling –pressures low 冷却不足-压强低

Under these conditions, the pressure is low on both the low pressure and the high pressure sides. These readings would indicate that the liquid refrigerant evaporates before the evaporator and will therefore absorb the heat energy in the wrong place thus resulting in insufficient cooling performance. By far the most likely outcome of this instance will be a lack of refrigerant within the system. Before the system is re gassed a leak detection process should occur. Leak detection should be carried out in line with DEFRA guidance. The environmental protection act of 1990 states that the deliberate release of refrigerant is banned. Oxygen free nitrogen pressure testing is now widely recommended.
在这些情况下，气压在高压端和低压端都低。这些数据可能说明液态制冷剂在进入蒸发器之前蒸发，从而会在不当位置吸收热能，导致制冷效果不足。目前为止，这一情况最有可能产生的结果是系统中制冷剂的缺乏。系统重新充气前应该进行一次泄漏测试。这一测试应该根据DEFRA手册进行。1990年环境保护条例规定蓄意释放制冷剂是被禁止的。现在广泛使用的是无氧氮气压力检测。
Poor cooling –pressures high 制冷不足- 压强高

Under these conditions the pressure is too high on both the low pressure side and the high pressure sides. These readings could indicate a selection of faults. Firstly there could be too much refrigerant in the system. This will lead to the refrigerant evaporating after the evaporator and will therefore absorb the heat energy in the wrong place thus resulting in insufficient cooling performance. An additional possible cause of this can be air in the system. This can result in the pressures being too high which will result in evaporation of the refrigerant occurring in the wrong location in the system. The final common possibility could be that the condenser is not managing to cool the refrigerant sufficiently. This could be caused by the cooling fan not working or the condenser being blocked/fins bent over.
在这些情况下，压强在高压端和低压端都非常高。这些数据可能显示几点故障：一是系统中的制冷剂过多。这将导致制冷剂离开蒸发器后仍存在蒸发现象，因此会在不当位置吸收热能，导致制冷效果不足。另一个可能原因是系统中的空气。这会导致压强过高，引起制冷剂的蒸发发生在系统中的不当位置。最后可能的原因是冷凝器无法完全冷凝制冷剂。原因是冷却风扇没有工作或冷凝器堵塞，叶片弯曲。
Poor refrigerant flow – does not cool/cools intermittently 制冷剂流动不畅- 不制冷或间歇制冷

Under these conditions, a vacuum is indicated on the low pressure side. Low pressure is indicated on the high pressure side. In most cases the refrigerant flow is being obstructed as moisture turns to ice at the expansion valve. This causes a temporary blockage resulting in the pressure in the high side fluctuating and the pressure in the low pressure side dropping due to a restricted supply to the compressor. There should not be any moisture in the system and it can be a clear indication that the dryer needs to be replaced along with the necessity to thoroughly vacuum down the system and recharge.
在这些情况下，说明低压端存在一个真