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After all leak check procedures are completed, refrigerant lines that may be exposed to
high and low ambient temperatures should be insulated. The suction lines should be
insulated with an industry accepted material of no less than ¾” wall thickness.
In case, need more information, please contact Tecumseh representative.
CONNECTIONS OF SUCTION & LIQUID LINE
AND REFRIGERANT PIPING.
For the service end refrigerant piping connections for the evaporator or unit cooler, 3-way
service valves are used. The details of service valve is given in the page No. 4 & 5 of this
booklet.
In case, the suction line is up flow, then use one standard size smaller. A suction
trap should be installed at the base of suction risers. Long radius elbows should be
employed to minimize pressure losses.
To prevent oxidation and scale forming inside the tubes it is recommended to flow
dry nitrogen through the tubing during the brazing operations. A light flow of about
¼ CFM is sufficient.
Assurance of adequate velocity, thus ensuring oil return capability (the tube size
must be limited to maintain velocities no less than 750 fpm for horizontal and
down flow and no less than 1500 fpm for up flow)
Assurance of acceptable pressure drop (The tube size should be limited to
maintain pressure drop no greater than the equivalent of a 2°F temperature drop.)
Assurance of satisfactory sound level (the tube size should be limited to
maintain velocities no greater than 3000 fpm.)
Horizontal suction lines should be sloped downward in the direction of the
compressor at least ½” per 10’ of line.
Please use only refrigeration grade copper tubes & flare nuts.
Always keep the tubes free of moisture and dirt and remove any burrs present on the tube.
The selection of the suction line sizes should be guided by the following criteria:
PRESSURE CONTROLS (MINI PRESSURE SWITCHES)
