Toshiba MMU-AP0091H service manual Procedure to Identify the Cause of Compressor Oil Shortage, 204

15-3. Procedure to Identify the Cause of Compressor Oil Shortage

Is there any disconnection, mis-cabling,	NO
or incorrect installation of sensors on the unit
of which the compressor has been replaced?

Correct miscabling or incorrect installation of the sensors: TK1: CN514/TK2: CN515 TK3: CN516/TK4: CN523

YES

Are the sensor characteristics of	NO
TK1, TK2, TK3 and TK4 sensors correct?

Sensor error ÆExchange

YES

Check oil-equalization circuit in the following procedure once the compressor is removed.

Check items and procedure for the oil-equalization circuit under when the compressor has been removed

	Check items	Position		Procedure
	Outdoor PMV1, 2, 3	A	1)	Pressurize with nitrogen through check joint of liquid pipe and check for
	leakage	B		pressure at check joint of discharge pipe.
	Check valve leakage			If pressure of check joint of discharge pipe is high, leakage from outdoor
	on main discharge pipe			PMV 1,2, 3 and check valve of main discharge pipe are possible.
				Exchange the parts.
			2)	If the pressure cannot be found, open outdoor PMV 1,2,3 fully and recheck
				pressure.
Check for				If the pressure from the discharge check joint is high, leakage from check
				valve of main discharge pipe is possible. Exchange the parts.
refrigerant
stagnation in	Check valve leakage of	C	3)	If gas leaks from the brazed discharge pipe where compressor has been
compressor	discharge pipe			removed, when pressurized with nitrogen from the check joint of the main
				discharge pipes, the discharge pipe check valves is possibly leaking.
				Exchange the parts.
	Check valve leakage of	D	4)	If gas leaks from the brazed oil-equalization pipe where compressor has
	oil-equalization circuit			been removed, when pressurized with nitrogen from the check joint of the
				discharge pipe, the check valve of oil-equalization circuit is a possibly
				leaking. Exchange the parts.
	SV3A valve leakage	E	5)	Pressurize with nitrogen with the check joint on the discharge pipe then open
	SV3B valve clogging	F		SV3B valve manually.
				If gas leaks from the brazed suction pipe where the compressor should be,
				there may be a leak in SV3A valve. Exchange the parts.
	SV3E valve clogging.	G	6)	Open SV3E valve manually while pressurizing with nitrogen using the check
	Clogging of oil-return	H		joint on the discharge pipe.
Check for oil	capillary			If there is no leakage at the brazed suction pipe where the compressor was
				removed, the SV3E valve or oil return capillary may be clogged.
shortage in
compressor				Exchange the parts.
	SV3D valve capillary	I	7)	Open SV3E valve manually while pressurizing with nitrogen from the check
	clogging.	H		joint of the discharge pipe.
	Clogging of oil-return			If there is no leakage at the brazed suction pipe where the compressor was
	capillary			removed, the SV3D valve/capillary or oil return capillary may be clogged.
				Exchange the parts.

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