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•
For best operation, keep tubing run as short as possible with a minimum num-
ber of elbows or bends.
•
Locations where the tubing will be exposed to mechanical damage should be
avoided. If it is necessary to use such locations, the copper tubing should be
housed to prevent damage.
•
If tubing is to be run underground, it must be run in a sealed watertight chase.
•
Use care in routing tubing and do not kink or twist. Use a good tubing bender
on the vapor line to prevent kinking.
•
Route the tubing using temporary hangers, then straighten the tubing and
install permanent hangers. Line must be adequately supported.
•
The vapor line must be insulated to prevent dripping (sweating) and prevent
performance losses. Armaflex and Rubatex are satisfactory insulations for this
purpose. Use 1/2" minimum insulation thickness, additional insulation may be
required for long runs.
•
Check Table 3 for the correct vapor line size. Check Table 4 for the correct liq-
uid line size.
7.5 Tubing Connections
Indoor coils have only a holding charge of dry nitrogen. Keep all tube ends sealed
until connections are to be made.
•
Use type "L" copper refrigeration tubing. Braze the connections with the follow-
ing alloys:
– copper to copper - 5%
– Silver alloy (no flux)
– copper to steel or brass - 35%
– silver alloy (with flux)
•
Be certain both refrigerant shutoff valves at the outdoor unit are closed.
•
Clean the inside of the fittings and outside of the tubing with steel wool or sand
cloth before soldering. Always keep chips, steel wool, dirt, etc., out of the inside
when cleaning.
•
Assemble tubing part way into fitting. Apply flux all around the outside of the
tubing and push tubing into stop. This procedure will keep the flux from getting
inside the system.
•
Remove the cap and schrader core from service port to protect seals from heat
damage.
•
Use an appropriate heatsink material around the copper stub and the service
valves before applying heat.
•
IMPORTANT: Do not braze any fitting with the TEV sensing bulb attached.
•
Braze the tubing between the outdoor unit and indoor coil. Flow dry nitrogen
into a service port and through the tubing while brazing.
•
After brazing – use an appropriate heatsink material to cool the joint and
remove any flux residue.
•
The service valves are not backseating valves. To open the valves, remove the
valve cap with an adjustable wrench. Insert a 3/16" or 5/16" hex wrench into the
stem. Back out counterclockwise.
•
Replace the valve cap finger tight then tighten an additional 1/2 hex flat for a
metal-to-metal seal.
7.6 Leak Testing
•
Pressurize line set and coil through service fittings with dry nitrogen to 150
PSIG maximum. Leak test all joints using liquid detergent. If a leak is found,
recover pressure and repair.
WARNING
DO NOT USE OXYGEN TO PURGE LINES OR PRESSURIZE SYSTEM FOR
LEAK TEST. OXYGEN REACTS VIOLENTLY WITH OIL, WHICH CAN
CAUSE AN EXPLOSION RESULTING IN SEVERE PERSONAL INJURY OR
DEATH.
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