
7
Guidelines Of Field-charging Air Conditioning Systems With Scroll Compressors
These guidelines are intended for use with Scroll compressors only with R, R07C, Ra, R0A, R07,
and R0A refrigerants. They do not apply to reciprocating compressors or competitive Scroll compressors.
Field-charging - Some Precaution Points
Scroll compressors have a very high volumetric efficiency and quickly pump a deep vacuum if there is
insufficient refrigerant in the system or if refrigerant is added too slowly. Operation with low suction pressure
will quickly lead to very high discharge temperatures. While this process is happening, the scrolls are not being
well lubricated - scrolls depend on the oil mist in the refrigerant for lubrication. A lack of lubrication leads to high
friction between the scroll flanks and tips and generates additional heat. The combination of heat of compres
-
sion and heat from increased friction is concentrated in a small localized discharge area where temperatures
can quickly rise to more than 00°C. These extreme temperatures damage the Scroll spirals and the orbiting
Scroll bearing. This damage can occur in less than one minute especially on larger compressors. Failure may
occur in the first few hours or the damage done during field charging may show up some time later.
Other typical field charging problems include undercharging, overcharging, moisture or air in the system etc.
In time each one of these problems can cause compressor failure.
Equipment
Minimal equipment is required for field charging. The minimum equipment required to do a satisfactory job is:-
Set of service gauges
Hoses
Vacuum pump
Vacuum gauge
Scales
Thermometer
Charging Hoses
Most field-charging is done using standard service hoses. Hoses are made in different colors with
different working pressures and with different leak rates but the most important point is the presence or
absence of Shredder valve depressors. Shredder valve depressors severely restrict the flow through the
service hoses. This slows evacuation and vapor charging dramatically. In most cases the Shredder depressor
can be removed but it is simpler to have one set of hoses with and one set without Shredder depressors.
Hose with Shredder valve Depressor
Hose without Shredder valve Depressor
Hose selection is important depending whether the system is being evacuated or charged. Charging liquid
from the cylinder into the liquid line should be carried out using an open hose connected to an unrestricted
fitting. This will reduce charging time.
Содержание A4MC 100ER
Страница 1: ...Ceiling Concealed D Series ACC D2 2007 ACC 75 D DR ACC100 D DR Models ...
Страница 50: ...48 Model AMC A4MC 75 100D ER Note All Dimension are in mm Outdoor Unit ...
Страница 53: ...51 Model ACC 75 100D vs AMC A4MC 75 100D Cooling Only 10 WIRING DIAGRAMS ...
Страница 54: ...52 Heat Pump Model ACC 75 100DR vs Model AMC A4MC 75 100ER ...