Telemark Cryogenics 1200 Instruction Manual page 25

Telemark Cryogenics Microprocessor Based Cryochillers
When installing the refrigerant lines it is essential to protect the lines and
fittings from the entrance of moisture, such as water vapour, which causes
rapid degradation of any foam type insulation. An effective vapour barrier is
best achieved by using the approved rubber based impact adhesive
followed by sealing of all glued edges with duct tape or 13mm electricians
type PVC tape.
If the lines have visible frosting or condensation is seen to leak from them
during defrost or standby, all of the line insulation must be replaced. 
Refrigeration line connections are recessed to protect against accidental
damage. When replacing a traditional cryotrap an adapter may be required,
the best solution however is to remove the old connections from the lines
replacing them with the stubs supplied in the units tool kit.
All copper-to-copper joints must be silver or hard soldered,
soft solder is unacceptable.
Inspect and clean all coupling faces. Ensure they are free from dents or
scratches. Small imperfections on the couplings of the refrigerant lines may
be rectified by using 1200 grade wet or dry mounted onto a glass plate.
Special care needs to be taken when handling VCR fittings. It is critical that
the faces are totally flat and square. Always purge lines through with dry
nitrogen to prevent contamination of lines. When using the 1200 grade wet
or dry ensure the abrasive pad is always dry.
It is recommended that the connections on the cryo-coil are male metal seal
couplings (i.e. those with the 'O' Ring groove) as these are more delicate
than the female, flat face seal half of the coupling.
Position the refrigerant lines to suit the installation. Bend the refrigerant line
as necessary. The minimum bend radius is 12 inches (300mm). Ensure at
least 5 inches (150mm) of straight line runs to the unit and to the feed-
through coupling.
It is vital that a new o-ring is used every time a connection
is made or broken. Always use the "O" ring removal tool
when removing the "O" ring. Take care not to damage the
mating surfaces of the connections.
Fig 10 Metal "O" Ring Removal Tool (part No: 22-8000-18)
Page 25 of 63
Revision 1.0.7 October 2018