52
. Troubleshooting
No.
Fault symptom
Possible cause
Explanation - Solution
4.
LED2 on FTC4 (Master)
is off.
(See Figure <4.5.1>)
<FTC4 (Master) powered on independent source>
1.
FTC4 (Master) is not supplied with 220 to
240V AC.
1. Check the voltage across the L and N terminals on the indoor power supply
terminal block. (See section 4.1.)
• When the voltage is not 220 to 240V AC, check for faulty wiring to power
supply.
• When the voltage is 220 to 240V AC, go to 2. below.
2.
There are problems in the method of
connecting the connectors.
2.
Check for faulty wiring between the connectors.
• When the connectors are wired incorrectly re-wire them correctly referring to
below. (See section 4.1 and a wiring diagram on the control and electrical box
cover.)
L
N
CN01
CN01
S1
S2
S3
• If no problem found with the wiring, go to 3. below.
3.
FTC4 (Master) failure.
3. Check the FTC4 (Master) control board.
• Check the fuse on FTC4 (Master) control board.
• Check for faulty wiring.
• If no problem found with the wiring, the FTC4 (Master) control board is faulty.
When LED1 on FTC4 (Master) is lit.
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.)
Incorrect setting of refrigerant address for
outdoor unit.
(None of the refrigerant address is set to "0".)
5
LED2 on FTC4
(Master) is blinking.
(See Figure <4.5.1>)
When LED1 is also blinking on FTC4 (Master).
Check for faulty wiring between FTC4 (Master) and outdoor unit.
Faulty wiring between FTC4 (Master) and
outdoor unit
When LED1 on FTC4 (Master) is lit.
1.
Faulty wiring in main controller
Multiple indoor units have been wired to a
single outdoor unit.
1. Check for faulty wiring in main controller.
The number of indoor units that can be wired to a single outdoor unit is one. Ad-
ditional indoor units must be wired individually to a single outdoor unit.
2.
Short-circuited wiring in main controller
2.,3. Remove main controller wires and check LED2 on FTC4 (Master). (See Figure
4.5.1.)
• If LED2 is blinking check for short circuits in the main controller wiring .
• If LED2 is lit, wire the main controller again and:
- if LED2 is blinking, the main controller is faulty;
- if LED2 is lit, faulty wiring of the main controller has been corrected.
3.
Main controller failure
6
LED4 on FTC4
(Master) is off.
(See figure <4.5.1>)
1.
SD memory card is NOT inserted into the
memory card slot with correct orientation.
1. Correctly insert SD memory card in place until a click is heard.
2.
Not an SD standards compliant memory card.
2. Use an SD standards compliant memory card. (Refer to section 4.9.)
LED4 on FTC4
(Master) is blinking.
(See Figure <4.5.1>)
1.
Full of data.
1. Move or delete data, or replace SD memory card with a new one.
2.
Write-protected.
2. Release the write-protect switch.
3.
NOT formatted.
3. Refer to "4.9 Using SD memory card".
4.
Formatted in NTFS file system.
4.
FTC4 is Not compatible with NTFS file system. Use an SD memory card formatted
in FAT file system.
7
No water at hot tap.
1.
Cold main off
1. Check and open stop cock.
2.
Strainer (field supply) blocked.
2. Isolate water supply and clean strainer.
8
Cold water at tap.
1.
Hot water run out.
1. Ensure DHW mode is operating and wait for DHW tank to re-heat.
2.
Prohibit, schedule timer or holiday mode se-
lected.
2. Check settings and change as appropriate.
3.
Heat pump not working.
3. Check heat pump – consult outdoor unit service manual.
4.
Booster heater cut-out tripped.
4. Check booster heater thermostat and press reset button if safe.
Reset button is located on the side of booster heater, covered with white rubber
cap. See component parts diagram (Installation manual of Hydrobox, section 3.) to
find out its position.
5.
The earth leakage circuit breaker for booster
heater breaker (ECB1) tripped.
5. Check the cause and reset if safe.
6.
The booster heater thermal cut-out has
tripped and cannot be reset using the manual
reset button.
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.
Immersion heater cut-out tripped.
7. Check immersion heater thermostat and press reset button, located on immersion
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.
Immersion heater breaker (ECB2) tripped.
8. Check the cause and reset if safe.
9.
3-way valve fault
9. Check plumbing/wiring to 3-way valve.
(i) Manually override 3-way valve using the main controller. (Refer to <Manual op-
eration> in section 7.2.) If the valve does not still function, go to (ii) below.
(ii) Replace 3-way valve coil. If the valve does not still function, go to (iii) below.
(iii) Replace 3-way valve. (Refer to the service manual.)
FTC4 (Master)
powered
from independent
source
Black
Hydrobox
control board
YELLOW
YELLOW
BLACK
BLACK
