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Installation Manual - A-VMH18DU,28TU,36QU,48PU-1
2
4
Fig. 9.3
Air Evacuation
9
Safety Precautions
Evacuation Instructions
Before using a manifold gauge and a vacuum
pump, read their operation manuals to make
sure you know how to use them properly.
Manifold Gauge
Compound gauge
Low pressure valve
High pressure valve
Charge hose
Charge hose
Vacuum pump
Pressure gauge
Low pressure valve
Fig. 9.1
1.
Connect the manifold gauge’s charge hose
to the service port on the outdoor unit’s low
pressure valve.
2.
Connect the manifold gauge’s charge hose
from the to the vacuum pump.
3.
Open the Low Pressure side of the manifold
gauge. Keep the High Pressure side closed.
4.
Turn on the vacuum pump to evacuate the system.
5.
Run the vacuum for at least 15 minutes, or until
the
micron gauge
reads
<400 microns
.
6.
Close the manifold gauge’s Low Pressure valve
and turn off the vacuum pump.
7.
Wait for 5 minutes, then
confirm that system
pressure remains below 500 microns.
NOTE:
If there is no change in system pressure,
unscrew the cap from the packed valve (high
pressure valve). If there is a change in system
pressure, there may be a gas leak.
8. Insert hexagonal wrench into the packed valve
(high pressure valve) and open the valve by
turning the wrench 1/4 counterclockwise.
Listen for gas to exit the system, then close the
valve after 5 seconds.
Flare nut
Cap
Valve body
Valve stem
Fig. 9.2
9. Watch the Pressure Gauge for one minute to make
sure that there is no change in pressure. It should
read slightly higher than the atmospheric pressure.
10.Remove the charge hose from the service port.
11. Using hexagonal wrench, fully open both the
high pressure and low pressure valves.
OPEN VALVE STEMS GENTLY
When opening valve stems, turn the hexagonal
wrench until it hits against the stopper.
DO NOT
try to force the valve to open further.
12.
Tighten valve caps by hand, then
seat caps
with a
wrench.
13.
On units with main and zone refrigerant
service valves, do not open main valves
until evacuation and leak detection is
complete.
CAUTION
system.
•
The outdoor unit does not need vacuuming.
DO NOT
open the outdoor unit’s gas and
liquid stop valves.
•
DO NOT
use refrigerant to
purge
the
main valves
zone
valves