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Mitsubishi Electric PURY-HP72 Service Handbook page 176

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[6-9 Evaluating and Adjusting Refrigerant Charge ]
Keep the unit running for 5 minutes after adjusting the
refrigerant amount to determine its adequacy.
Gradually add refrigerant from
the service port on the low -
pressure side.
Keep the unit running for 5 minutes after adjusting the
refrigerant amount to determine its adequacy.
Gradually add refrigerant from
the service port on the low -
pressure side.
CAUTION
Do not release the extracted refrigerant into the air.
CAUTION
Charge liquid refrigerant (as opposed to gaseous refrigerant) into the system.
If gaseous refrigerant is charged into the system, the composition of the refrigerant in the cylinder will change and may
result in performance loss.
HWE13080
Start
Turn on SW4 (922) on the OC.
Put all indoor units in the test run mode
and run the units in cooling mode.
Has the initial start-up
mode been completed?
YES
Has it been at least
30 minutes since
start up?
YES
Is the TH4 value of the OC and OS
at or below 100°C [212°F]?
YES
Has the operating frequency
of the compressor on the OC and OS
become stable?
YES
5°C[9°F]≤SH on all indoor units.
YES
Does the following hold true ?
5°C[9°F]≤SC11≤15°C[27°F]
(on the BC)
YES
NO
Does the following hold true ?
15°C[27°F]≤SC16 (on the BC)
YES
NO
Does the following hold true ?
TH4≤95°C[203°F] on the OC and OS
YES
Adjustment complete
Turn off SW4 (922) on the OC.
- 165 -
YES
NO
Operation of the Refrigerant Amount Adjust Mode
When the unit is the refrigerant amount adjust mode, the LEV on the
indoor unit does not open as fully as it normally does during cooling
operation to secure subcooling.
Note
1) SW4-3 on the OS is invalid, and the unit will not go into the refrigerant
NO
amount adjust mode.
2) There may be cases when the refrigerant amount may seem adequate
for a short while after starting the unit in the refrigerant amount adjust
mode but turn out to be inadequate later on (when the refrigerant
system stabilizes).
3) High pressure must be at least 2.0MPa[290psi] to enable a proper
adjustment of refrigerant amount to be made.
4) Refrigerant amount adjust mode automatically ends 90 minutes after
NO
beginning.
When this happens, by turning off the SW4-3 and turning them back on,
the unit will go back into the refrigerant amount adjust mode.
Gradually add refrigerant from
NO
the service port on the low-
pressure side.
NO
Keep the unit running for 5 minutes
after adjusting the refrigerant amout
to determine its adequacy.
NO
Has the LEV opening been stabilized
on all indoor units ?
YES
NO
Does the following hold true?
SC11 < 5°C[9°F]
YES
Gradually add refrigerant from
Gradually draw out
the service port on the low-
refrigerant from the service
pressure side.
port on the low pressure side.
NO
NO
GB

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