Toshiba MMU-AP0091H service manual Flow Selector Unit FS Unit, 171

171

9-8-2. Flow Selector Unit (FS Unit)

Leakage of SVD valve or SVS valve, etc; Positions to be checked and check code when a trouble such as miswiring occurred.

						Phenomenon which appears as result
				Correspon		(Corresponding indoor unit or flow selector unit)					Example of
	Trouble
Part name			Operation mode	ding indoor			May become	l Abnormal		Judgment and position to be checked	refrigerant
	mode			unit	Not	Not		cooling sound	Detection of		flow
							almost normal
					cooled	heated		¡ Circulating	check code
							capacity
								sound
			All heating operation	All		¡				• TC1 is lower than normal indoor unit.
	Clogging		Mainly cooling, part heating operation	Heating unit						• Temperature of suction gas pipe at indoor side of the flow selector
			Mainly heating, part cooling operation	Heating unit						unit is lower than that of normal FS unit.
			All cooling operation (SV11 ON)	All						• Compared with normal indoor unit, TCJ is higher.
								¡ SVD circuit –		• Suction gas pipe at outdoor side of the flow selector unit is hot.	A
	Leakage		Mainly cooling, part heating operation	Cooling unit	¡
								SVS circuit		• Refrigerant circulating sound is heard in bypass from SVD valve
			Mainly cooling, part heating operation	Cooling unit
										to SVS valve.
			All cooling operation (SV11 OFF)	All			¡	¡ SVD circuit		• Refrigerant circulating sound is heard from SVD valve circuit.
SVD valve										• TCJ is high and SH is little. (Liquid pack)
										• Temperature of TCJ and TC1 become high similar to heating. (All
	Miswiring/		All cooling operation (SV11 ON)	All						heating circuit)
					¡			¡ SVD circuit		• Discharge gas pipe at outdoor unit side of the flow selector unit is	B
			Mainly cooling, part heating operation	Cooling unit
	Misinstallation									rather hot.
	of coil		Mainly cooling, part heating operation	Cooling unit						• Refrigerant circulating sound is not heard from SVS valve, but it is
	SVD ↔	SVS								heard from SVD valve.
			All heating operation	All					L18 “Flow	• Gas pipe at indoor side of the flow selector unit is cold. (Cooling
			Mainly cooling, part heating operation	Heating unit		¡		¡ SVS circuit	selector unit	circuit, Liquid pack)	C
										• Refrigerant circulating sound is not heard from SVD valve, but it is
			Mainly heating, part cooling operation	Heating unit					error”	heard from SVS valve.
			All cooling operation	All						• TCJ is higher than normal indoor unit.
	Clogging		Mainly cooling, part heating operation	Cooling unit	¡			¡ SVSS circuit		• Gas pipe at indoor side of the flow selector unit is not cold.
			Mainly heating, part cooling operation	Cooling unit						• Refrigerant circulating sound is heard from SVSS valve.
SVS valve									P19 “4-way	• Compared with normal indoor unit, TCJ is low.
			All heating operation	All					valve reversal
	Leakage					¡		¡ SVS circuit	error”	• Temperature of suction gas pipe at outdoor side of the flow
										selector unit is higher than that of normal flow selector unit.
			Mainly cooling, part heating operation	Heating unit
										• Refrigerant circulating sound is heard from SVS valve circuit.
			Mainly heating, part cooling operation	Heating unit
			All heating operation	All				l Indoor unit,		• In start time, when exchanging mode from cooling to heating after
	Clogging		Mainly cooling, part heating operation	Heating unit			¡
								flow selector unit		defrost operation, refrigerant shock sound may be heard.
			Mainly heating, part cooling operation	Heating unit
			All cooling operation (SV11 ON)	All						• Refrigerant circulating sound may be heard from SVDD valve
							¡	¡ SVDD circuit		circuit.
			Mainly cooling, part heating operation	Cooling unit
										• Suction gas pipe at outdoor unit side of the flow selector unit may
			Mainly heating, part cooling operation	Cooling unit
	Leakage									be hot.
			All heating operation	All						• Refrigerant circulating sound may be heard from SVDD valve
SVDD			Mainly cooling, part heating operation	Heating unit			¡	¡ SVDD circuit
										circuit.
valve			Mainly heating, part cooling operation	Heating unit
	Miswiring/		All cooling operation (SV11 ON)	All						• Refrigerant circulating sound may be heard from SVDD valve
	Misinstallation						¡	¡ SVDD circuit		circuit.
	of coil		Mainly cooling, part heating operation	Cooling unit						• Suction gas pipe at outdoor unit side of the flow selector unit may
			Mainly heating, part cooling operation	Cooling unit
	SVD ↔	SVS								be hot.
			All heating operation	All				l Indoor unit,		• In start time, when exchanging mode from cooling to heating after
			Mainly cooling, part heating operation	Heating unit			¡
								flow selector unit		defrost operation, refrigerant shock sound may be heard.
			Mainly heating, part cooling operation	Heating unit