(b) Add dye to the system to detect very small and hard to detect
Use a halide torch to locate leaks.
1 Use the torch to heat the copper element until it is cherry red.
2 Move the hose over the system. A change of color indicates a
a Pale blue--no leaks.
b Yellow-green--small leak.
c Purplish-blue--large leak.
(d) Use an electronic leak detector. Follow the manufacturer's
Connect the manifold gauges.
(a) Connect the blue hose from the compound gauge to the suction
(b) Connect the red hose from the high side gauge to the high side
Connect the yellow hose from the center on the manifold to the
Check the oil in the vacuum pump.
Open both valves on the manifold.
Read the instructions for the pump you are using.
Start the vacuum pump.
(6) Run the vacuum pump until the gauge reads 25 inches to 27 inches
vacuum (the time depends on the size of the system).
Close both valves on the manifold.
Turn off the vacuum pump per the instructions on the pump.