Midea MT-200R20E20

14
Table 4-5
Item Description Image Notice
1
Connect the (low pressure side) hose
of a pressure gauge to the outdoor
unit gas pipe stop valve.
Before performing vacuum drying, make sure that
alltheoutdoorunitstopvalvesarermlyclosed.
2
Connect the hose to the vacuum
pump.
1.Mixingofpumplubricantwithcompressoroil
could cause compressor malfunction and a one-
way valve should therefore be used to prevent
vacuum pump lubricant seeping into the piping
system.
2. Using a vacuum pump with a discharge in
excessof4L/sandaprecisionlevelof0.02mmHg
is recommended.
3
Connect the outdoor unit gas pipe
stop valve to water tank gas pipe
4
Connect the outdoor unit liquid pipe
stop valve to water tank liquid pipe
5
Start the vacuum pump and then
open the pressure gauge valves to
start vacuum the system.
6
After 15-20 minutes, close the
pressure gauge valves.
7
After a further 5 to 10 minutes check
the pressure gauge. If the gauge has
returned to zero, check for leakages
in the refrigerant piping. If the gauge
is no change, then vaccum drying is
OK.
8
Re-open the pressure gauge valves
and continue vacuum drying for at
least 20 minutes and until a pressure
di󰀨erenceof756mmHgormorehas
been achieved. Once the pressure
di󰀨erenceofatleast756mmHghas
been achieved, continue vacuum
drying for 20 minutes.
9
Close the pressure gauge valves and
then stop the vacuum pump.
10
After 1 hour, check the pressure
gauge. If the pressure in the piping
has not increased, the procedure
isnished.Ifthepressurehas
increased, check for leakages.
After vacuum drying, keep the hoses connected
to the pressure gauge and to the outdoor
unit stop valves, in preparation for refrigerant
charging.
4.5 Refrigerant charge
• Pipe length is 2~20m.
• If the pipe length is less than 10m, there is no need to add additional refrigerant charge.
• If the pipe length is more than 10m, adding additional refrigerant charge is necessary, and the rule is 20g/m for the additional pipe.