Mitsubishi Electric EHSD-MED Service Manual page 51

No. Fault symptom
4 LED2 on FTC is off. <FTC powered on independent source>
(See "6. WIRING
1. FTC is not supplied with 220 to 240 VAC.
DIAGRAM".)
2. There are problems in the method of
connecting the connectors.
3. FTC failure
When LED1 on FTC is lit:
Incorrect setting of refrigerant address for
outdoor unit
(None of the refrigerant address is set to "0".)
5 LED2 on FTC is When LED1 is also blinking on FTC:
blinking.
Faulty wiring between FTC and outdoor unit
(See "6. WIRING
When LED1 on FTC is lit:
DIAGRAM".)
1. Faulty wiring in main remote controller
Multiple indoor units have been wired to a sin-
gle outdoor unit.
2. Short-circuited wiring in main remote controller 2.,3. Remove main remote controller wires and check LED2 on FTC. (See Figure
3. Main remote controller failure
6 LED4 on FTC is off. 1. SD memory card is NOT inserted into the
(See "6. WIRING memory card slot with correct orientation.
DIAGRAM".)
2. Not an SD standards compliant memory card
LED4 on FTC is 1. Full of data
blinking.
2. Write-protected
(See "6. WIRING
3. NOT formatted
DIAGRAM".)
4. Formatted in NTFS file system
7 No water at hot tap. 1. Cold main off
2. Strainer (local supply) blocked
8 Cold water at tap. 1. Hot water run out.
2. Prohibit, schedule timer or holiday mode se-
lected or demand control input (IN4) or smart
grid ready (switch-off command).
3. Heat pump not working
4. Booster heater cut-out tripped.
5. The earth leakage circuit breaker for booster
heater breaker (ECB1) tripped.
6. The booster heater thermal cut-out has tripped
and cannot be reset using the manual reset
button.
7. Immersion heater cut-out tripped.
8. Immersion heater breaker (ECB2) tripped.
9. 3-way valve fault
OCH712C
Possible cause
51
Explanation - Solution
1. Check the voltage across the L and N terminals on the indoor power supply
terminal block. (See "7. FIELD WIRING".)
• When the voltage is not 220 to 240 VAC, check for faulty wiring to power
supply.
• When the voltage is 220 to 240 VAC, go to 2. below.
2. Check for faulty wiring between the connectors.
• When the connectors are wired incorrectly re-wire them correctly referring
to below. (See "7. FIELD WIRING". and a wiring diagram on the control
and electrical box cover.)
L
N
Modified settings
White
CN01
(Separate power
Hydrobox
supply to S1
control board
the hydrobox)
S2
S3
• If no problem found with the wiring, go to 3. below.
3. Check the FTC control board.
• Check the fuse on FTC control board.
• Check for faulty wiring.
• If no problem found with the wiring, the FTC control board is faulty.
Recheck the refrigerant address setting on the outdoor unit.
Set the refrigerant address to "0".
(Set refrigerant address using SW1(3–6) on outdoor controller circuit board.)
Check for faulty wiring between FTC and outdoor unit.
1. Check for faulty wiring in main remote controller.
The number of indoor units that can be wired to a single outdoor unit is one.
Additional indoor units must be wired individually to a single outdoor unit.
5.2.1. in installation manual)
• If LED2 is blinking check for short circuits in the main remote controller wiring.
• If LED2 is lit, wire the main remote controller again and:
- if LED2 is blinking, the main remote controller is faulty;
- if LED2 is lit, faulty wiring of the main remote controller has been corrected.
1. Correctly insert SD memory card in place until a click is heard.
2. Use an SD standards compliant memory card. (Refer to section 5.6 in instal-
lation manual)
1. Move or delete data, or replace SD memory card with a new one.
2. Release the write-protect switch.
3. Refer to "5.6 Using SD memory card" in installation manual.
4. FTC is Not compatible with NTFS file system. Use an SD memory card for-
matted in FAT file system.
1. Check and open stop cock.
2. Isolate water supply and clean strainer.
1. Ensure DHW mode is operating and wait for DHW tank to re-heat.
2. Check settings and change as appropriate.
3. Check heat pump – consult outdoor unit service manual.
4. Check booster heater thermostat and press reset button if safe.
Reset button is located on the side of booster heater, covered with white rub-
ber cap. See "4. PART NAMES AND FUNCTIONS" to find out its position.
5. Check the cause and reset if safe.
6. Check resistance across the thermal cut-out, if open then the connection is
broken and the booster heater will have to be replaced.
Contact your Mitsubishi Electric dealer.
7. Check immersion heater thermostat and press reset button, located on im-
mersion heater boss, if safe. If the heater has been operated with no water
inside it may have failed, so please replace it with a new one.
8. Check the cause and reset if safe.
9. Check plumbing/wiring to 3-way valve.
(i) Manually override 3-way valve using the main remote controller. (Refer to
<Manual operation> in section "9-4. Service menu".) If the valve does not
still function, go to (ii) below.
(ii) Replace 3-way valve.