CMW
070517
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Refrigerant Piping Procedure
When installing/routing the line set, cap both ends of each tube to prevent material or debris from entering the tubing.
Prior to connecting the piping, loosely connect the refrigerant gauges to the service ports of the suction and liquid line service
valves. Purge the charging hoses with dry nitrogen and tighten the hose connections. Remove the service valve caps and turn
the valve stem clockwise (half of a complete turn) in order to unseat the valve and open the service port. The valve comes in a
back seated position from the factory. Keep the piping port sealed until ready to connect to the vacuum pump.
Cleanliness is of the utmost importance. All horizontal suction piping should be pitched toward the condensing unit 1/2” for
every 10’ of pipe. During any brazing procedure, purge the fitting with dry nitrogen at a slow rate to prevent formation of highly
abrasive copper oxide. Make sure there are no obstructions to the flow which would cause pressure to build up and the brazed
fittings to leak. After confirming that there are no leaks, insulate suction line with Armaflex (1/2” wall thickness) or comparable
insulation. Seal all seams using Armaflex 520 foam insulation adhesive or equivalent. Wrap each seam using line set tape.
Liquid Line Piping Procedure
Use of a 1/4” OD copper tube liquid line is required. When making connections, keep the ends sealed until ready to fit the tube.
First connect the supplied refrigerant drier close to the liquid service valve (king valve) on the receiver. Downstream, connect the
moisture-indicating sight glass in an easily visible location. Run the tubing to the evaporator unit (fan coil unit) location and fit
to the liquid line stub from the evaporator unit (fan coil unit). Energize the evaporator unit (fan coil unit) and set the temperature
controller to call for cooling. This will activate the liquid line solenoid valve. Uncap the suction pipe to prevent obstructed
nitrogen flow. Open the nitrogen to allow a slow flow and braze the liquid line fitting. Do not shut off the nitrogen and power
until the suction line is brazed.
Suction Piping Procedure
Slide Armaflex insulation over the tubing for the entire length of the tube and keep the end of the tube sealed during this
procedure. Keep the tubing sealed while running the connection points and fit the suction tube to the evaporator unit (fan coil
unit) outlet connection. Install a Schrader access valve at the outlet of the evaporator unit (fan coil unit) to allow for superheat
checking. If there are brazed fittings along the length of the tube, apply the insulation after leak testing.
After Piping is Run (Ready for the Brazing Process
)
Energize the evaporator unit (fan coil unit) and set the temperature controller to call for cooling. Open the liquid line service
valve and bleed the nitrogen through both the liquid and suction line. Loosen the suction gauge hose to relieve pressure during
the brazing process. Braze the connections and cool them off quickly.
Leak Testing
Using dry nitrogen, pressurize the system to 200 psi. Check to see if there is a noticeable pressure drop. If so, locate and fix leak.
With pressure at 200 psi, check for leaks with a refrigerant leak detector and/or soap bubbles. Confirm the pressure holds at 200
psi for 30 minutes. If not, check again for leaks and repair, then perform another leak test. When it is confirmed that there are no
leaks, release the nitrogen pressure and leave the solenoid valve energized.
INSTALLING THE CONDENSING UNIT
