Measuring equipment and how to use it

The given chapter completely is devoted to the description of the measuring equipment necessary for search and elimination of malfunctions. Recommendations for application of this equipment are here too resulted.

Attention: Before beginning of realization of the works connected to the system of air-conditioning, it is necessary to familiarize with the safety precautions described in the first chapter of the second part of this book.

Manometers

As shown in figure the complete set of manometers is one of the important devices of the system of air-conditioning. They are applied at the discharge, charge, allocation, and as the device measuring working pressure from the high and low sides in the system of air-conditioning.

Key rules of using:

• At installation of the device in the system, pay attention not to mix manometers of high and low pressure (it may serve as the reason of breakage of manometers).
• At work with vacuum, not to apply manometers without a discharge scale (not only it is impossible to learn a condition of vacuum, but because of moving of a pointer to the opposite side, it may serve as the reason of failure of a manometer).
• Central connection (В): it is used at refuelling, release of the refrigerant and creation of vacuum.
• Connection on the part of a high pressure (С): joins to the service armature of the compressor on the part of a high pressure and it is used for checking the system from the high pressure side.
• Connection on the part of low pressure (А): joins to the service armature of the compressor on the part of low pressure and it is used for checking the system on the low pressure side.

Attention: It is impossible to mix refrigerants R-12 and R-134a.

Hoses

Hoses are necessary for connection of the compressor with a manometer, and hoses of various colors are applied to each refueling gate.

Recommended colors of hoses:

Dark blue color hose

It is applied to connection on the low pressure side (incorporates to union " A " of the manometer).

Green color hose

It is applied to the refrigerant, release and refuelling (incorporates to union " B " of the manometer).

Red color hose

Serves for connection on the high pressure side (incorporates to union " C " of the manometer).

Before using hoses, they are necessary for checking up on:

• presence of cracks on a hose;
• presence of impurity in a hose (at presence of impurity they clear the refrigerant);
• belliness – А

Attention: It is impossible to mix refrigerants R-12 and R-134a.

Gas detector

The gas detector is intended for checking of outflow of the gas - refrigerant system of air-conditioning. This procedure is one of the major sequences of checking, therefore it needs to be carried out precisely and strictly. The gas-refrigerant of the system of air-conditioning may filter from different places, i.e. such places of connections as the union, the compressor, the service branch pipe, the filling aperture, the evaporator, the receiver-dehydrator.

Recommendations for checking performance

As the gas - refrigerant is heavier than air, checking of outflow needs to be carried out in prospective places of outflow as it is possible below, and the sensitive element of the detector should be always established on the bottom side of a connecting part.

During checking of outflow of gas from all connections and connecting muffs they delete surpluses of oil and due to presence of the refrigerant in oil, wrong work of the detector is prevented.

Smoke of cigarettes on the place of checking, gas - refrigerant and other gases can serve as the reasons of false operation of the detector. Therefore, as the correct way of checking of gas outflow depends on sensitivity of the gas detector, a site of checking should be clean and preferably whenever possible it is carried out on lowland places. Besides such checking needs to be carried out in the well-ventilated places without starting the engine.

If on any connecting site there will be an outflow, then this site this site is either tightened more strongly and if necessary on this site they replace a sealing ring and carry out checking anew as described above.

Thermometer

The thermometer is applied to check the characteristics of the system of air-conditioning. For measurement of temperature and humidity, the water thermometer is usually used – А.

However, for more effective check of air-conditioners, as it is shown in figure, they use the special device for measurement of temperature and humidity. This device on the end of a wire has the thermode installed, and after having inserted it into the ventilating aperture, it is possible to observe indications outside of the automobile. Therefore, using of the device shown on figure (B) would create convenience to check characteristics of the air-conditioner as it allows to observe pressure and temperature simultaneously.

Vacuum pump

If in the system there is moisture and air, it becomes the reason of various malfunctions. Therefore, the vacuum pump plays the important role, performs work on removal of moisture and air.