Danfoss VRJ, Application Manuallines

Application Guidelines

21

AB141686422149en-US0401

Installation

Vacuum evacuation and  
moisture removal

When brazing the compressor fittings, do not 
overheat the compressor shell, which could 
severely damage certain internal components 
due to excessive heating. Use of a heat shield 
and/or a heat-absorbent compound is highly 
recommended. For brazing the suction and 
discharge connections, the following procedure 
is advised:

• 

Make sure that no electrical wiring is 
connected to the compressor.

• 

Protect the terminal box and compressor 
painted surfaces from torch heat damage 
(see diagram).

• 

Use only clean refrigeration-grade copper 
tubing and clean all connections.

• 

Purge nitrogen or CO2 through the 
compressor in order to prevent against 
oxidation and flammable conditions. The 
compressor should not be exposed to the 
open air for extended periods.

• 

Use of a double-tipped torch is 
recommended.

• 

Apply heat evenly to area A until the brazing 
temperature is reached. Move the torch 
to area B and apply heat evenly until the 
brazing temperature has been reached there 
as well, and then begin adding the brazing 
material. Move the torch evenly around 
the joint, in applying only enough brazing 
material to flow the full circumference of the 
joint.

• 

Move the torch to area C only long enough 
to draw the brazing material into the joint, 
but not into the compressor.

• 

Remove all remaining flux once the joint has 
been soldered with a wire brush or a wet 
cloth. Remaining flux would cause corrosion 
of the tubing.

Ensure that no flux is allowed to enter into the 
tubing or compressor. Flux is acidic and can cause 
substantial damage to the internal parts of the 
system and compressor. 

The PVE oil used in VRJ compressors is highly 
hygroscopic and will rapidly absorb moisture 
from the air. The compressor must therefore not 
be left open to the atmosphere for a long period 
of time. The compressor fitting plugs shall be 
removed just before brazing the compressor.

 Before eventual unbrazing the compressor 

or any system component, the refrigerant charge 
must be removed from both the high and low 
pressure sides. Failure to do so may result in 
serious personal injury. Pressure gauges must be 
used to ensure all pressures are at atmospheric 
level.

For more detailed information on the appropriate 
materials required for brazing or soldering, please 
contact the product manufacturer or distributor. 
For specific applications not covered herein, 
please contact Danfoss Commercial Compressors 
for further information.

Moisture obstructs the proper functioning 
of both the compressor and the refrigeration 
system. 

Air and moisture reduce service life and 
increase condensing pressure, which causes 
abnormally high discharge temperatures that 
are then capable of degrading the lubricating 
properties of the oil. The risk of acid formation 
is also increased by air and moisture, and this 
condition can also lead to copper plating. All 
these phenomena may cause both mechanical 

and electrical compressor failures. The typical 
method for avoiding such problems is a vacuum 
pump-down executed with a vacuum pump, thus 
creating a minimum vacuum of 0.02 in Hg (500 
µm Hg). Please refer to Bulletin “Vacuum pump 
down and dehydration procedure”. 

Be sure to follow all government regulations 
regarding refrigerant reclamation and storage.

Compressor connection

Heat shield

C

B

A