6
Service and Maintenance
The indoor hydrobox must be serviced once a year by a qualified individual. Ser-
vicing and maintenance of the outdoor unit should only be done by a Mitsubishi
Electric trained technician with relevant qualifications and experience. Any electri-
cal work should be done by a tradesperson with the appropriate electrical quali-
Error Codes
Code
Error
L3
Circulation water temperature overheat protection
L4
DHW tank water temperature overheat protection
Indoor unit temperature thermistor (THW1, THW2, THW5B, THW6, THW7, THW8,
L5
THW9) failure
L6
Circulation water freeze protection
L8
Heating operation error
L9
Low primary circuit flow rate detected by flow sensor or flow switch (flow switches 1, 2, 3)
LA
Pressure sensor failure
en
LB
High pressure protection
LC
Boiler circulation water temperature overheat protection
LD
Boiler temperature thermistor (THWB1) failure
LE
Boiler operation error
LF
Flow sensor failure
LH
Boiler circulation water freeze protection
LJ
DHW operation error (type of external plate HEX)
LL
Setting errors of DIP switches on FTC control board
LP
Out of water flow rate range for outdoor heat pump unit
P1
Thermistor (Room temp.) (TH1) failure
P2
Thermistor (Ref. liquid temp.) (TH2) failure
P6
Anti-freeze protection of plate heat exchanger
J0
Communication failure between FTC and wireless receiver
J1 - J8
Communication failure between wireless receiver and wireless remote controller
E0 - E5
Communication failure between main remote controller and FTC
E6 - EF
Communication failure between FTC and outdoor unit
E9
Outdoor unit receives no signal from indoor unit.
EE
Combination error between FTC and outdoor unit
U*, F*
Outdoor unit failure
A*
M-NET communication error
Note: To cancel error codes please switch system off (Press button F4(RESET) on main remote controller).
29
fications. Any maintenance or 'DIY' fixes done by a non-accredited person could
invalidate the Warranty and/or result in damage to the hydrobox and injury to the
person.
Action
Flow rate may be reduced. Check for;
• Water leakage
• Strainer blockage
• Water circulation pump function (Error code may display during filling
of primary circuit, complete filling and reset error code.)
Check the immersion heater and it's contactor.
Check resistance across the thermistor.
See Action for L3.
Check and re-attach any thermistors that may have become dislodged.
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.
Check pressure sensor cable for damage or loose connections.
• Flow rate of the heating circuit may be reduced. Check water circuit.
• Plate heat exchanger may be clogged. Check the plate heat exchanger.
• Outdoor unit failure. Refer to outdoor unit service manual.
Check if the setting temperature of the Boiler for heating exceeds the re-
striction. (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
Check resistance across the thermistor.
See Action for L8. Check the status of the boiler.
Check flow sensor cable for damage or loose connections.
Flow rate of the heating circuit from the boiler may be reduced. Check for
• water leakage
• strainer blockage
• water circulation pump function
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. (primary / sanitary)
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).
Check the installation Table 4.3.1
Check remote controller settings (Service menu / heat pump flow rate
range)
See Action for L3.
Check resistance across the thermistor.
Check resistance across the thermistor.
See Action for L3.
Check for correct amount of refrigerant.
Check connection cable for damage or loose connections.
Check wireless remote controller's battery is not flat.
Check the pairing between wireless receiver to wireless remote controller.
Test the wireless communication. (See the manual of wireless system)
Check connection cable for damage or loose connections.
Check that the outdoor unit has not been turned off.
Check connection cable for damage or loose connections.
Refer to outdoor unit service manual.
Check both units are switched on. Check connection cable for damage or
loose connections. Refer to outdoor unit service manual.
Check combination of FTC and outdoor unit.
Refer to outdoor unit service manual.
Refer to outdoor unit service manual.
