Toshiba HWS-1402XWHM3-E, HWS-802XWHT6-E How to diagnose by error code, 2TWO, 3TWI, Two, Tho

9-3-4. How to diagnose by error code

Defect mode detected by the water heat exchange

									O ... Possible
									× .... Not possible
				Diagnostic functional operation					Number of
Check								Determination and action	abnormalities	Detailed
code						Backup	Automat		for	item
				Operational cause
						present	ic reset		confirmation
	Pump or flowing quantity error
	1) Detected by TC sensor
	TC	63°C is detected in the heating or							4	74
	hot water supply heat pump operation
	(except for defrosting).							1. Almost no or little water flow.
								• Not enough vent air
	2)Detected by flow switch abnormality
								• Dirt clogging in the water piping
	When no signal of the flow switch is							system.	2	74
	showing 2 min after the built-in pump
								• The water piping is too long.
	operation started.
								• Installation of buffer tank and
A01
	3)Detection of chattering abnormality in					×	×	secondary pump
	the flow switch input
	Chattering detection: Detects input								4	74
	changes (OFF⇔ON) 4 times within
	10 seconds during operation.
	4)Disconnection of the flow switch
	connector							1. Disconnection of the flow switch
	When the stopped built-in pump starts							connector.	2	74
	its operation, the flow switch status is							2. Defect of the flow switch.
	detecting "water flow".
	Temperature increase error (heating)					Heating		1. Check the water inlet, water outlet
								and heater outlet (TWI, TWO, THO)
	When one of the TWI, TWO and THO					O
A02							O	sensors.	1	75
	sensors exceeds 70°C.					Hot water
								2. Defect of the backup heater (defect
						×
								automatic reset thermostat).
	Temperature increase error (hot water					Heating		1. Check the hot water cylinder sensor
A03	supply)					O	O	(TTW).	1	76
	When the TTW sensor exceeds 85°C.					Hot water		2. Check the hot water cylinder thermal
						×		cut-out.
	Antifreeze operation							1. Almost no or little water flow.
	1)TWO>20°C condition:							• Dirt clogging in the water piping
	2×TC+TWO < -12°C is detected.							system.
	2)TWO			20°C condition:				• The water piping is too long.
								2. Check the heater power circuit.
	TC+TWO < 4°C is detected.								Heating2
								• Power supply voltage, breaker,
A04	3)TWI		10°C is detected during			O	×		Hot water2	77
								power supply connection
	defrosting.
									Cooling4
								3. Set the presence of the backup
								heater.
								4. Check the water inlet, water outlet
								and heat exchange (TWI, TWO, TC)
								sensors.
	Piping antifreeze operation							1. Check the heater power circuit.
	Activating the heater under the condition							• Power supply voltage, breaker,
	of TWO<4orTWI<4orTHO<4 does not							power supply connection
A05	achieve TWO,TWI,THO				5°C after 30	O	O	2. Check the water inlet, water outlet	1	78
	min elapsed.							and heater outlet sensors (TWI,.
								TWO, THO).
								3. Disconnection of the backup heater.

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