Mitsubishi Electric EHSE-YM9EC Service Manual page 45

Error code Title and display conditions
L9 Low primary circuit (Zone2 side) flow rate
detected by flow switch
Note: " 3" is displayed in "Request code: 569" in
"Running information".
LC Boiler circulation water temperature overheat
protection
<DHW/Heating/LP/FS/OS>
Error code displayed when THWB1 detects a
temperature ≥80ºC for 10 consecutive seconds
or THWB2 detects a temperature ≥80ºC for 10
consecutive seconds
LD Boiler temperature thermistor (THWB1, THWB2)
failure
LE Boiler operation error
<Heating>
Boiler is running and THW6 detects a
temperature <30ºC for consecutive 60 minutes.
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
P1 Indoor unit temperature thermistor (TH1A/TH1B)
failure
P2 Indoor unit temperature thermistor (TH2) failure
P6 Anti-freeze protection of plate heat exchanger
<Cooling>
The error code displayed when Ref. liquid temp.
(TH2) stays at −5ºC or lower for 10 seconds after
compressor operates for 6 minutes.
OCH590B
Possible Cause
1. Insufficient system head
2. Reduced flow in primary water circuit
due to 1 or more of the following;
Faulty pump, insufficient air purge,
blocked strainer, leak in water circuit.
3. Terminal wire has become detached
or loose wiring.
4. Flow switch fault
5. Incorrect setting of the SW3-3
6. FTC board failure
1. The set temperature for Boiler is too
high.
2. Flow rate of the heating circuit from the
boiler may be reduced.
Refer to error codes (P1/P2/L5/LD).
1. THW6 has become detached from its
holder.
2. Incorrect wiring between FTC (OUT10)
and the boiler
3. Boiler fuel has run out or the system is
OFF.
4. Boiler failure
5. FTC board failure
Disconnection or loose connection of flow
sensor
Flow rate of the heating circuit from the
boiler may be reduced.
1. D HW tank water temp. thermistor
(THW5) has become detached from its
holder.
2. F low rate of the sanitary circuit may be
reduced.
Incorrect setting of DIP switches
1. Boiler operation
2. 2-zone temperature control
3. Multiple outdoor units control
Refer to error codes (P1/P2/L5/LD).
Refer to error codes (P1/P2/L5/LD).
<Cooling>
1. Reduced water flow
• Clogged filter
• Leakage of water
2. Low temperature
• Low load
• Inlet water is too cold.
3. Defective water pump
4. Defective outdoor fan control
5. Overcharge of refrigerant
6. Defective refrigerant circuit (clogs)
7. Malfunction of linear expansion valve
45
Diagnosis and action
1. If more head required either add an pump
of the same size or replace existing pump.
2. Check circulation pump (See "10-6.
Checking Component Parts' Function" for
how to check).
Open purge valve to remove trapped air.
Check the strainer for blockages.
Check the primary water circuit for leaks.
Check that the flow amount is within the
recommended range.
3. Visually check the IN7 terminal and reat-
tach if necessary.
4. Electrically test to determine fault.
5. Check the SW3-3 setting.
6. Replace board.
1. Check if the set temperature for Boiler for
heating exceeds the restriction. (See the
manual for the thermistors "PAC-TH011HT-E")
2. Check for
• water leakage
• strainer blockage
• water circulation pump function
1. Visually inspect location and reattach as
necessary.
2. See the manual of the thermistors "PAC-
TH011HT-E".
3. Check the status of the boiler.
4. Check the status of the boiler.
5. Replace board.
Check flow sensor cable for damage or loose
connection.
Check for
• water leakage
• strainer blockage
• water circulation pump function
1. C heck for disconnection of DHW tank water
temp. thermistor (THW5).
2. Check for water circulation pump function.
1. 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).
2. 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).
3. For multiple outdoor units control, check DIP
SW1-3 is set to ON on FTC (slave) that runs
DHW operation .
1., 2. Check water piping.
3. Check water pump.
4. Check outdoor fan motor.
5., 6. Check operating condition of refrigerant circuit.
7. Check linear expansion valve.