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8.4.3. Creation of depression in system

NOTE
Every time when opening system it is necessary to create depression for protection against hit of air and moisture. After installation of any element it is necessary to support depression in system approximately within 15 min. The elements of system opened for repair have to be under the influence of depression within 30 min.

If the engine does not work, carry out the following procedures.

Fig. 8.60. Situation "is closed"


Attach a set of control manometers to compressor unions. Close gates of lines of the high and low pressure (fig. 8.60).
Make sure that coolant from system is merged.
Attach the central hose of a set of manometers to an entrance branch pipe of the vacuum pump.
Turn on the vacuum pump and open gates of high and low pressure.
Approximately in 10 min. be convinced that the manometer of low pressure shows depression lower than 94,39 kPa (0,96 kgfs/cm2). If depression does not manage to be received, it indicates leakage of system. In this case eliminate leakage, as shown below.
1. Close both gates of a set of manometers and switch off the vacuum pump.
2. Load system with coolant from the capacity (about 0,4 kg).
3. Define the place of leak by a techeiskatel.
4. Again merge coolant and create depression in system. If leaks are not revealed, continue to create depression in system.
Turn on the vacuum pump.
Open both valves of a set of manometers until depression of 94,39 kPa (0,96 kgfs/cm2) (fig. 8.61) is created.

Fig. 8.61. Situation "is opened"


After the manometer of low pressure shows depression about 94,39 kPa (0,96 kgfs/cm2), continue to create depression within 15 min.
After 15 min. finding of system under the influence of depression close both gates of a set of manometers and switch off the vacuum pump. Disconnect a hose from the vacuum pump. The system is ready for charging coolant.

Actions with the system charging gate

Fig. 8.62. The scheme of installation at action with the system charging gate



Before connection of the gate to container with coolant turn its handle to capacity counterclockwise.
Establish a disk in extreme top situation by rotation counterclockwise.
Attach the central hose to the gate union.
Rotation of the handle of the gate clockwise punch an opening in a tight top part.
Weaken an inhaling of a nut of fastening of the central hose to the central union of control manometers.
Let out the air within several seconds, then tighten a nut.

System charging vaporous coolant
Install the gate of container with coolant in the situation stated above in the section "Actions with the System Charging Gate".

NOTE
This operation is carried out for system charging by coolant in a vaporous state through a contour of low pressure. At vertical position of container with coolant the last moves in system in the form of steam.

Open the gate of a contour of low pressure and adjust its situation so that pressure on the manometer of low pressure did not exceed 412 kPa (4,2 kgfs/cm2).
That pressure of vapors in the container with coolant slightly exceeded pressure in system, place container in a vessel with warm water (temperature about 40 °C).
Start the engine on accelerated single to the course and turn on the conditioner.

NOTE
You keep the container with coolant in vertical position to exclude hit of the liquefied coolant in system through the line of absorption that can cause damage of the compressor.


Fig. 8.63. Situation "is closed" a contour of low pressure


Fill system with the required amount of coolant then close the gate of a contour of the low pressure (fig. 8.63).
Amount of the filled coolant: 500 ±25 g.
At the lowered speed of filling with coolant ship the container with coolant in warm water (temperature about 40 °C).

ATTENTION
On immerse the container with coolant in the warmed-up water with the temperature above 52 °C by no means.
It is forbidden to warm up capacity a blowtorch or in the drying camera.

System charging liquid coolant
After a vacuum purge of system completely close gates of high and low pressure.

NOTE
This operation is carried out for charging of the discharged system by coolant in liquid state through a contour of high pressure. At the provision of capacity upside down coolant moves in system in the form of liquid.

ATTENTION
It is forbidden to make system charging through a contour of high pressure at the working engine. At charging liquid coolant low pressure do not open the gate.

Install the gate of container with coolant in the situation stated above in the section "Actions with the System Charging Gate".
Completely open the gate of high pressure, having placed the container with coolant in situation upside down.
Load system with the required amount of coolant, determining its weight by scales. Excessive charging will lead to excess of pressure of forcing (in a contour of high pressure). Upon termination of charging close the gate of high pressure.
Amount of the filled coolant: 500±25 g.
After system charging the required amount of coolant close the gate of control manometers.
By means of a techeiskatel be convinced of lack of leaks from system.

NOTE
Before removal of control manometers it is recommended to check work of system.

Check of tightness of system
In all cases when existence of leak of coolant is supposed or the works connected with a detachment of elements or weakening of an inhaling of connections are performed, carry out check of tightness of system by means of an electronic techeiskatel.
Check the moment of an inhaling of connections of pipelines. When weakening an inhaling delay connections the specified moment. By means of a techeiskatel be convinced of lack of leak of gas.
If after a connection inhaling leak is not eliminated, discharge system, separate connection and check the condensing surfaces for existence of damages. Even slightly damaged details of connections are subject to obligatory replacement.
Check amount of compressor oil and if necessary restore it to norm.
Load system and check its tightness. If leaks are not revealed, make a vacuum purge and charging of system.

Check of refrigerating capacity of system
Install control manometers.
Start the engine and leave it to work with a frequency of rotation of bent shaft 2000 mines-1, install temperature switch in the situation corresponding to giving in salon of most cooled air, and the fan switch – in the situation corresponding to the maximum speed of rotation.
Discover all glasses and doors.

Fig. 8.64. Installation of the dry thermometer in a giving nozzle in salon of the cooled air


Place the dry thermometer in a giving nozzle in salon of the cooled air (fig. 8.64).
Place the psychrometer in the place of an intake of air in a refrigerating contour of the conditioner.
Check indications of the manometer of high pressure which have to be within 1,373–1,575 kPa (14–16 kgfs/cm2). If indications exceed the top specified limit, water the condenser. If indications are lower than the lower limit, cover a forward part of the condenser.
Check indications of the dry thermometer which have to be within 25–35 °C.

Fig. 8.65. Psikhrometrichesky schedule


Determine relative humidity of air by the psikhrometrichesky schedule by comparison of temperatures on the moistened and dry thermometer of the psychrometer placed in the place of an intake of air in the conditioner (fig. 8.65).

NOTE
Having determined values of temperature by the moistened and dry thermometer on an evaporator entrance, it is possible to define relative humidity of air. Example: temperature on the dry and moistened thermometer on an entrance of the evaporator makes respectively 25 °C and 19,5 °C. The point of intersection of the corresponding dashed lines on graphics gives value of relative humidity (60%).

Determine temperature by the dry thermometer placed in a snivel of supply of the cooled air in salon and calculate a difference of values of temperature on the dry thermometer on an intake of air and on the dry thermometer on an air outlet in salon.

Fig. 8.66. Schedule of calculation of relative humidity


Make sure that the point of intersection of lines of relative humidity and a difference of temperatures is in borders of the area which is painted over black that indicates compliance of characteristics of refrigerating capacity to norm (fig. 8.66).