16
Installation Procedure
English
Installation Procedure
Step 8 Vacuum drying the refrigerant
circuit
HIGH PRESSURE LEAK TEST WITH DRY
NITROGEN(before opening valves)
In order to determine if there are any leaks in the
refrigerant piping system prior to vacuum drying, the
system must be pressure tested using a dry nitrogen leak
test.
First, pressurize the system with dry nitrogen up to
100 psi. Hold for 5 minutes and observe if the pressure
decreases. If the pressure does decrease, a leak is likely
present and should be repaired before repeating the high
pressure leak test.
If the system holds pressure at 100 psi for 5 minutes, then
proceed to increase the pressure to 300 psi and again
determine if there may be leaks by waiting 5 minutes and
observing if there is a pressure drop in the system.
If the system holds pressure at 300 psi, then proceed to
increase the pressure to 600 psi. Hold for one hour and
observe if there is any loss in pressure after 1 hour. Repair
any leaks, if necessary, and repeat the high pressure leak
check, or proceed to evacuate and vacuum dry the system
as indicated in the next steps.
CAUTION
• Perform this triple evacuation procedure to remove
all noncondensables and moisture from the system
before charging. Failure to do so will result in reduced
performance and shorter equipment life.
The time required to perform each evacuation will depend
on the capacity (CFM) of the vacuum pump used.
1 Use a micron gauge to measure the degree of vacuum
during the evacuation step. The micron gauge should
be placed as far as possible from the pump in order to
ensure an accurate reading.
2 Install the high and low side hoses to the manifold
gauge, and to the high and low service ports of the
outdoor unit service valves.
3 Attach a vacuum pump to the common hose of the
manifold set.
4 To ensure optimal performance, verify that the vacuum
pump’s oil has been changed recently.
5 If desired, first verify the manifold gauge and hoses are
leak free.
6 Energize the vacuum pump and begin vacuuming.
7 Evacuate until 4000 microns is achieved, for at least
10 minutes.
8 Close the gauge manifold valve, shut off the vacuum
pump, and remove the common hose.
9 Connect the hose to the nitrogen pressure regulator
of the dry nitrogen cylinder and bleed the hose by
opening the end of the common hose closest to the
manifold.
10 Open the manifold valves and slowly bring the system
pressure to atmosphere (0 psig). Hold the system at
atmospheric pressure for 15 minutes.
11 Close the manifold and nitrogen cylinder and remove
the common hose.
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