Danfoss DSH090 Application Manual page 60

Scroll compressors, DSH090 to DSH600 | Application
Figure 64: Heavy
HEAVY
do not lift
manually
Piping assembly
Good practices for piping assembly is a pre-requisite to ensure compressor life time (system cleanliness, brazing
procedure etc.)
Table 37: System cleanliness
Circuit contamination possible cause:
Brazing and welding oxides
Particles and burrs
Moisture and air
Brazing procedure:
• Brazing operations must be performed by qualified personnel.
• Make sure that no electrical wiring is connected to the compressor.
• To prevent compressor shell and electrical box overheating, use a heat shield and/or a heat-absorbent compound.
• Clean up connections with degreasing agent
• Flow nitrogen through the compressor.
• It is recommended to use double-tipped torch using acetylene to ensure a uniform heating of connection.
• For discharge connections brazing time should be less than 2 minutes to avoid NRVI damages if any.
• To enhance the resistance to rust, a varnish on the connection is recommended.
DSH compressors connectors are made of steel copper coated, which benefit to protect against corrosion and
facilitate adhesion during brazing operation.
As per standards practice in the refrigeration industry, Danfoss Commercial Compressor recommend to use of silver
cadmium free solder alloy and flux (added or flux coated rods). The significant silver content in these brazing alloy
will help the brazing operation, providing an excellent fluidity and a limited heating temperature. It will bring also a
good resistance to corrosion, a proper elongation compatible with system vibration, and good behavior under
thermal variation improving the strength of connection and limiting fractures and refrigerant leaks. (Crucial with
A2L refrigerants) A typical content of 34% Ag (Silver) is recommended by Danfoss.
The use of self-flux alloys (as phosphorous alloys) is not recommended by Danfoss. This type of brazing require a
higher working temperature, that may overheat the connectors, damaging the thin layer of copper ,resulting in
phosphides creation and joint zone embrittlement.
For more detailed information see " Brazing technique for compressors connectors" AP192186420580.
© Danfoss | Climate Solutions | 2022.10
Figure 65: Correct
Requirement:
During brazing, flow nitrogen through the system.
Remove any particles and burrs generated by tube cutting and hole drilling.
Use only clean and dehydrated refrigeration grade copper tubing.
Opened compressor must not be exposed to air more than 20 minutes to avoid moisture captured by oil.
Figure 66: Incorrect Figure 67: Handling
1 Slings
2 Spreader bars
3 Frame
AB288965961751en-001402 | 60
1
2
3