Hitachi YUTAKI Series - WEH - Water Electric Heater; DHWT - Domestic Hot Water Tank

Troubleshooting
Service Manual
228
Troubleshooting of accessories
SMGB0066 rev.0 - 12/2009
 
   
Electric power supply
problems in WEH
Control signals from Systems Controls
miss-connected or wrongly connected
Check connections between System
Controller and WEH
Terminals7,8,9fromSystemController
connectedtoTerminals7,8,9WEH
respectively
Check Voltage (230V) between
terminals 8/9 and 8/7 in WEH and also
in System Controller
Check Power Supply in System
Controller
Check Voltage (230V) between
Terminals A1 & A2 in Contactor Coils
of WEH
Repair connections if required
WEH has no Power
Terminals L1~L3 have no voltage
(440V/230V)
ELB,CBorFuseprotectingWEHare
activated.Thereissomeshort-circuit,
wrong connection or any earth leak
Check cable connections in WEH power
circuit. Repair circuit and replace Fuse
or Switch ON ELB/CB
Check possible miss connections in
WEH power circuit
Check cable connections in WEH power
circuit. Repair circuit.
Check Electric Resistances:
26,5Ohms(5%Tolerance)
Replace Resistances if required
Problems in Water Circuit
due to low Water Pressure or
no Water in Water Circuit
LWPS is OFF
[WaterPressure<0,1MPa]
Check Water Pressure
(mustbe>0,1MPa)
Fill Water Circuit with enough pressure
(< 0.1MPa)
Check if Water Circuit is locked
Check Valves and Water Circuit to
ensure water circulation
Check if there is Water leaks
Check Water circuit and repair leaks
if exist
Problems in Water Circuit
due to excesive Water
Temperature in Water Circuit
Thermostat Cut-Out activated
[Excesive water temperature (<85ºC)]
Check Water Temperature and
Thermostat state
Push reset button for thermostat re-start
 
Troubleshooting-DHWT-200/300E/S-2,5H1E
   
"Electric power supply
problems in DHWT"
"Control signals from Systems Controls
miss-connected or wrongly connected"
"Check connections between System
Controller and DHWT"
Terminals11,12fromSystemController
connectedtoTerminals3,4DHWT
respectively
"Check Voltage (230V) between terminals
N/3 and N/4 in DHWT"
"Check Power Supply in System
Controller"
Check Voltage (230V) between Terminals 7
& 8 in Relay coils of DHWT
Repair connections if required
"DHWT has no Power Terminals L~N
have no voltage (230V)"
"ELB,CBorFuseprotectingDHWTare
activated.
Thereissomeshort-circuit,wrong
connection or any earth leak"
"Check cable connections in DHWT power
circuit. Repair circuit and replace Fuse or
Switch ON ELB/CB"
Check possible miss connections in DHWT
power circuit
"Check cable connections in DHWT power
circuit. Repair circuit."
"Check Electric Resistances:
17,7Ohms(5%Tolerance)"
Replace Resistances if required
"Problems in Water
Circuit due to low Water
Pressure or no Water in
Water Circuit"
[WaterPressure<0,1MPa]
"Check Water Pressure
(mustbe>0,1MPa)"
Fill Water Circuit with enough pressure (<
0.1MPa)
Check if Water Circuit is locked
Check Valves and Water Circuit to ensure
water circulation
Check if there is Water leaks
"Check Water circuit and repair leaks if
exist"
"Problems in Water
Circuit due to excesive
Water Temperature in
Water Circuit"
"Thermostat Cut-Out activated
[Excesive water temperature (<90ºC)]"
"Check Water Temperature and Thermostat
state"
"Push reset button for thermostat re-start"