Air Source Screw Water Chiller Unit – Installation Operation and Maintenance Manual
36
6
.3.2.13 Refrigerant Recharge
6
.3.2.13.1 Procedure
1)
Operation steps
(1) Ensure that vacuum drying is completed.
(2) Calculate the amount of refrigerant to be recharged (based on the recommended value, actual
liquid pipe dimensions, and length specified in section 7.3.3.1).
(3) Use an electric balance to weigh up the required refrigerant.
(4) Connect the refrigerant cylinder, pressure gauge, and the service valve of outdoor unit with
flexible ducts. Vent out the air in the flexible ducts and the branch of pressure gauge. Then, fill in
the refrigerant in liquid state.
(5) Write down the amount of recharged refrigerant on the nameplate of the outdoor unit.
Precautions
①
The amount of recharged refrigerant must be calculated based on relevant technical instructions
specified in the accessories of indoor unit, instead of based on the current, pressure, or exhaust
temperature. Because the system current, pressure, and exhaust temperature vary with the ambient
temperature and pipe length.
②
If the temperature is low, the refrigerant cylinder can be warmed by using warm water or hot air,
instead of being heated up above fires.
6
.3.2.14 Thermal Insulation
Common thermal insulation is applied to refrigerating devices and pipes. To be specific, devices and pipes
are wrapped by solid and porous thermal materials. Together with proper moisture-proof and protective
measures, a thermal insulation structure is created. The thermal insulation structure varies with the type of
thermal material. Although the thermal insulation performance of this traditional method is not remarkable,
the simple structure, convenient construction, and cost effectiveness make it broadly used in the industry.
6
.3.2.14.1 Thermal Insulation of Refrigerant Pipe
1)
Operation procedure
Refrigerant pipe construction
Thermal insulation (except for the connectors)
Air tightness test
Thermal insulation of connectors
Thermal insulation of connectors such as the soldering area, expanding area, and flange can
be performed only after the air tightness test is passed.
2)
Purposes
(1) When the air conditioner is running, the temperature of gas pipe and liquid pipe can be either too
high or too low. Without thermal insulation, the refrigerating performance can be affected. In
addition, the compressor may be burned.
(2) The gas pipe temperature is very low during refrigerating. If no thermal insulation measure is
