Leak Check And System Evacuation - Trane MCC Series Installation Operation & Maintenance

Leak Check and System Evacuation

Leak Check
After the connection operation of
refrigerant lines to both the outdoor
and indoor unit is completed, the
field brazed connections must be
checked for leaks. Pressurize the
system through the service valve
with dry nitrogen to 400 psi. Use
soap bubbles or other leak-checking
methods to ensure that all field joints
are leak free. If not, release pressure,
repair and repeat leak test.
System Evacuation
•
After completion of leak check,
evacuate the system.
•
Attach appropriate hoses from
manifold gauge to gas and liquid
line pressure taps.
Note : Unnecessary switching of
hoses can be avoided and
complete evacuation of all lines
leading to sealed system can be
accomplished with manifold
center hose and connecting branch
hose to a cylinder of R410A/R32
and vacuum pump.
•
Attach center hose of manifold
gauges to vacuum pump.
•
Evacuate the system to hold a
-760 mmHg vacuum.
•
Close off valve to vacuum pump
and observe the micron gauge.
If gauge pressure rised above
-760 mmHg in one (1) minute,
then evacuation is incomplete
or the system has a leak.
•
If vacuum gauge does not rise
above -760 mmHg in one (1)
minute, the evacuation should
be complete.
•
With vacuum pump and micron
gauge blanked off, open valve on
R410A cylinder and allow refrigerant
pressure to build up to about
40 PSIG.
10
•
Close valve on the R410A/R32
supply cylinder. Close valves on
manifold gauge set and remove
refrigerant charging hosed from
liquid and gas gauge ports.
•
Leak test the entire system. Using
proper procedures and caution,
repair any leaks found and repeat
the leak test.
Refrigerant Charging Procedure
Charge refrigerant through the gauge
port on the liquid line until pressure
at gauge is up to 120-150 PSI.
Once the charge enters the system,
backseat (open) the liquid line service
valve and disconnect the charging
line and replace the cap on the
gauge port.
Gaseous Charging
This procedure is accomplished
with the unit operating. Electrical
connections must be complete.
Do not proceed until the system is
ready to operate.
www.ttair.co.th | Tel : 02-385-0728 | E-mail : sales@ttair.co.th | LINE ID : @ttair
Procedure
•
Connect R410A/R32 drum with gauge
manifold to the Schrader valves
(pressure taps) on the compressor
discharge and suction lines.
•
Turn on power to the unit. Allow
the system to run for five to ten
minutes to stabilize operating
conditions.
•
Once proper airflow is established,
observe the suction and head
pressure gauges on the gauge
manifold. Pressure reading should
fall approximately at the normal
points. Add or remove refrigerant
(gas only) as required to obtain
correct head and suction pressures.
Check suction line superheat and
condenser sub-cooling to ensure
the unit is operating properly.
•
Disconnect all power to the unit.
•
Remove the charging system from
the unit and close the opening in
the bottom of the control box with
the pivotal cover before attempting
to replace access panel.
Liquid pressure Suction pressure
Electrical connection
Liquid line
Suction line
Refrigerant
R410A/R32
(Liquid charge only)
Service hose
Figure 11
Vacuum pump
MCC-SVN01A