Mitsubishi Electric EHWT17D-MHEDW, Data Book

Page: 62 / 131

Error Codes (FTC)
Code Error Action
L3 Circulation water temperature overheat protection
Flow rate may be reduced. Check for;
• Water leakage
• Strainer blockage
• Water circulation pump function (Error code may display during fill -
ing of primary circuit, complete filling and reset error code.)
L4 DHW tank water temperature overheat protection Check the immersion heater and it’s contactor.
L5
FTC temperature thermistor (THW1, THW2, THW5A,
THW5B, THW6, THW7, THW8, THW9) failure
Check resistance across the thermistor.
L6 Circulation water freeze protection See Action for L3.
L8 Heating operation error Check and re-attach any thermistors that have become dislodged.
L9
Low primary circuit flow rate detected by flow sen -
sor or flow switch (flow switches 1, 2, 3)
See Action for L3. If the flow sensor or flow switch itself does not
work, replace it.
Caution: The pump valves may be hot, please take care.
LC
Boiler circulation water temperature overheat pro-
tection
Check if the setting temperature of the Boiler for heating exceeds the
restriction. (See the manual of the thermistors "PAC-TH012HT-E")
Flow rate of the heating circuit from the boiler may be reduced.
Check for
• water leakage,
• strainer blockage
• water circulation pump function.
LD Boiler temperature thermistor (THWB1) failure Check resistance across the thermistor.
LE Boiler operation error See Action for L8. Check the status of the boiler.
LF Flow sensor failure Check flow sensor cable for damage or loose connections.
LH Boiler circulation water freeze protection
Flow rate of the heating circuit from the boiler may be reduced.
Check for
• water leakage
• strainer blockage
• water circulation pump function.
LJ DHW operation error (type of external plate HEX)
• Check for disconnection of DHW tank water temp. thermistor
(THW5B).
• Flow rate of the sanitary circuit may be reduced.
• Check for water circulation pump function.
LL
Setting errors of DIP switches on FTC control
board
For boiler operation, check that DIP SW1-1 is set to ON (With Boiler)
and DIP SW2-6 is set to ON (With Mixing Tank).
For 2-zone temperature control, check DIP SW2-7 is set to ON (2-
zone) and DIP SW2-6 is set to ON (With Mixing Tank).
LP Out of water flow rate range
Check the installation Table 6.6.2
Check remote controller settings (Service menu / heat pump flow
rate range)
See Action for L3.
J0
Communication failure between FTC and wire-
less receiver
Check connection cable for damage or loose connections.
P1 Thermistor (Room temp.) (TH1) failure Check resistance across the thermistor.
P2 Thermistor (Ref. liquid temp.) (TH2) failure Check resistance across the thermistor.
P6 Anti-freeze protection of plate heat exchanger
See Action for L3.
Check for correct amount of refrigerant.
J1 - J8 Communication failure between wireless receiver
and wireless remote controller
Check wireless remote controller’s battery is not flat.
Check the pairing between wireless receiver to wireless remote con-
troller.
Test the wireless communication. (See the manual of wireless sys-
tem)
E0 - E5 Communication failure between main remote
controller and FTC
Check connection cable for damage or loose connections.
E6 - EF Communication failure between FTC and C.B.
Check connection cable for damage or loose connections.
Refer to service handbook.
E9 C.B. receives no signal from FTC.
Check connection cable for damage or loose connections. Refer to
service handbook.
U*, F* Refrigerant or brine circuit failure Refer to Error Codes (C.B.) or service handbook.
Note: To cancel error codes please switch system off (Press button F4(RESET) on main remote controller, for 3 seconds).
B-259
Water to Water Heat Pump (WTW)
7
Cylinder
unit/
Hydrobox/GSHP/WTW
Cylinder
unit/
Hydrobox/GSHP/WTW