Toshiba MMU-AP0181MH, MMU-AP0151MH Leakage check for SV3C valve, Clogging for SV3E valve

Check code name	Check code name				Cause of operation
[H07]	Oil level down		1. Valves of balance pipes closed.
	detection protection		2. Miscabling or misinstallation of TK1 to TK4 sensors
			3.	TK1 to TK4 sensor error
			4.	Gas leak or oil leak of all outdoor units
			5.	Refrigerant stagnation of compressor case
			6.	SV3A, 3B, 3D, 3C, 3E valve error
			7.	Clogging of oil return circuit from oil separator
			8.	Clogging of oil-equation circuit system
Are TK1, TK2, TK3, and		NO
					Correct miswiring and misinstallation.
TK4 sensors connected correctly?					TK1: CN514, TK2: CN515	)
Is there no sensor coming-off or misinstallation?					( TK3: CN516, TK4: CN523

YES

In some cases, it may be difficult to check the leakage of clogging in the following condition of refrigerant stagnation in low ambient temperature condition.

In this case, take a longer operating time prior to check.

(Criterion: Discharge temperature of TD1 and TD2 are 60°C or higher)

(*1)

a)	Leakage check for SV3A valve (For multiple outdoor unit system)
	•	Turn off the power supply, take off connector of SV3A valve, and then start a test operation after power-ON.
	•	Check the temperature change at secondary side of SV3A valve during operation . (• in the figure.)
		→ If temperature is raised, it is a leakage of SV3A valve. Replace SV3A valve.
b)	Leakage check for SV3C valve
	•	Turn off the power supply, take off connector of SV3C valve, and then start a test operation after power-ON.
	•	After operation for several minutes, check temperature at secondary side of SV3C valve. (‚ in the figure.)
		→ If temperature is high (equivalent to discharge temperature TD), it is a leakage of SV3C valve. Replace
		SV3C valve.

Are TK1 and TK2 sensors connected correctly? Is there no sensor coming-off or misinstallation?

Are sensor characteristics normal?

YES

Check leakage of SV6 circuit.

Normal

NO

Characteristics-2

Abnormal

Correct miswiring and misinstallation.

(TS1: CN504, TS2: CN522)

Sensor error Replace

Replace defective parts.

(Even if there is leakage from SV3C valve does not occur, temperature of SV3C valve at secondary side

rises during operation. When the checked temperature is equivalent to TD temperature, it is a leakage of

SV3C valve. Replace SV3C valve.)

c) Clogging check for SV3B valve (For multiple outdoor unit system)

• While outdoor unit is operated, set up SW01/02/03 = [2] [1] [3] to 7-segment display [Hr] [ 2], and push SW04

for 2 seconds or more.

75

Check whether there is setup missing					Abnormal		Set up to cooling only operation mode.
							Item code (DN) OF
of cooling only indoor unit.
							Cooling only operation mode: 0001
		Normal			NO
Are characteristics of TK1 to TK4 normal?
					Characteristics-4		Sensor error Replace
		YES
Check gas leak of outdoor unit.					Abnormal		Specify a position where
Check oil stain in the							gas leaked and repair it.
( machine room of outdoor unit. )								(Recharge, refill oil.)
		Normal
					NO
Is the flow selector unit normal?							Repair the flow selector unit.
	YES
Check accumulation of			NO		( 1) Check leakage of		YES
					solenoid valve. (SV3C)				Replace defective parts
refrigerant in compressor case.					Check clogging.
	Refrigerant accumulation				(SV3E)
						No leakage or clogging
Correct accumulation of
refrigerant in compressor case,
reset power supply and					( 2) Check clogging in oil
then start operation.							YES
					recovery circuit of the oil separator.				Replace defective parts
					(Capillary, Strainer)
					Check clogging of SV3D valve.
Check oil level judgment						No clogging
of each compressor.
		SW01/02/03=1/16/1		are
		displayed on 7-		segment display.
Are all the oil levels appropriate?
			NO
	YES						Clogging
Eliminate cause of accumulation.					Check clogging of oil-equation circuit.				Replace defective parts
					( 3)

Indoor/outdoor PMV error

(Cause of refrigerant accumulation) Discharge check valve error, etc.

• Set up SW02 = [9], and turn on SV3A, SV3B, SV3C valves. (7-segment display [Hr] [ 3–])

• While outdoor unit is operating, check temperature change at secondary side of SV3B valve. (ƒ in the figure.)

→ If temperature does not rise (equivalent to suction temperature), it is a clogging of SV3B valve.

Replace SV3B valve.

d) Clogging for SV3E valve

Reset the power supply.

ò

Referring to “Valve forced open/close function” of the outdoor unit, check ON/OFF operation (Sound, coil surface temp up) of SV3E valve is performed.

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Start test operation in COOL or HEAT mode.

ò

After operation for several minutes, check the pipe temperature at the secondary side of SV3E valve whether temperature changes or not. If it is equivalent to outside temperature, clogging of SV3E is considered.

(„ in the figure.)

(Reference)

If SV3E valve is clogged, temperature of all TK1, TK2, TK3, and TK4 do not change.

(*2) Clogging check for SV3D valve of oil return circuit from oil separator

a)Oil return circuit

•While outdoor unit is operating, check temperature (secondary side of capillary) on oil return circuit. (… in the figure.)

→If temperature is low equivalent to suction temperature), a clogging of strainer of oil return circuit or capillary is considered. Repair the clogged part.

b)Clogging check for SV3D valve

•While outdoor unit is operating, set up SW01/02/03 = [2] [1] [3] to 7-segment display [Hr] [ 2], and push SW04 for 2 seconds or more.

•Set up SW02 = [6], and turn on SV3D valve. (7-segment display [Hr] [ 3d])

•If temperature is low at secondary side of the valve or it does not change, clogging of valve, capillary, or strainer is considered. († in the figure.)

(Reference) If refrigerant is accumulated in the compressor case, oil level short may be judged.