55
OCH722A
No.
Fault symptom
Possible cause
Explanation - Solution
20 Noise during hot water
draw off typically
worse in the morning.
1.
Loose airing cupboard pipework.
1.
Install extra pipe fastening clips.
2.
Heaters switching on/off.
2.
Normal operation no action necessary.
21
Mechanical noise
heard coming from
the unit.
1.
Heaters switching on/off.
Normal operation no action necessary.
2.
3-way valve changing position between
DHW and heating mode.
3.
Heat pump unit (compressor) running
22
Water circulation
pump runs for a short
time unexpectedly.
Water circulation pump jam prevention
mechanism (routine) to inhibit the build-up of
scale.
Normal operation no action necessary.
23 Milky/Cloudy water
(Sanitary circuit)
Oxygenated water
Water from any pressurised system will release oxygen bubbles when water is
running. The bubbles will settle out.
24
Heating mode has
been on standby for
a long time (does
not start operation
smoothly.)
The time of “Delay” set in “Economy settings
for pump” is too short. (Go to “Service menu”
→ “Auxiliary settings” → “Economy settings for
pump”).
Increase the time of “Delay” in “Economy settings for pump” .
25
The heat pump unit
that was running in
the heating mode
before power failure
is running in the
DHW mode after
power recovery.
The heat pump unit is designed to run in an
operation mode with a higher priority (i.e. DHW
mode in this case) at power recovery.
• Normal operation.
• After the DHW max. operation time has elapsed or the DHW max. temperature
has been reached, the DHW mode switches to the other mode (ex. Heating
mode).
26
The energy monitor
value seems not cor
-
rect.
Note:
There could be some
discrepancies between
the actual and the
calculated values.
If you seek for accuracy,
please make sure to
connect power meter(s)
and heat meter to FTC
board. Both should be
locally supplied.
1.
Incorrect setting of the energy monitor
1. Check the setting by following the procedure below.
(1) Check if the DIP switch on FTC board is set as the table below.
Consumed electric energy
SW3-4
Electric energy meter
(Local supply)
OFF
Without
ON
With
(2) In the case external electric energy meter and/or heat meter is not used,
check if the setting for electric heater and water pump(s) input is correct by
referring to <Energy monitor setting> in "8-5. Service menu".
(3) In the case external electric energy meter and/or heat meter is used, check if
the unit of output pulse on external meter matches with the one set at the main
remote controller by referring to <Energy monitor setting> in "8-4. Service
menu".
2.
Non-connectable type of external meter
(local supply) is connected.
2. Check if the external meter (local supply) is connectable type by referring to
<Energy monitor setting>" in "8-5. Service menu".
3.
External meter (local supply) failure
3. Check if signal is sent to IN8 to IN10 properly. (Refer to section 5. WIRING
DIAGRAM)
Replace the external heat meter if defective.
4.
FTC board failure
4. Check the FTC control board.
• Check for faulty wiring.
• If no problem found with the wiring, the FTC control board is faulty. Replace the
board.
27
Heat pump is forced
to turn ON and OFF.
Smart grid ready input (IN11 and IN12) is used,
and switch-on and off commands are input.
Normal operation no action necessary.
Delivered heat energy
SW3-8
Heat meter
(Local supply)
OFF
Without
ON
With
Annual Maintenance
It is essential that the heat pump unit is serviced at least once a year by a qualified individual. Any spare parts required should be purchased from Mitsubishi Electric.
NEVER
bypass safety devices or operate the unit without them being fully operational.
<Annual maintenance points>
Use the Annual Maintenance Log Book as a guide to carrying out the necessary checks on the heat pump unit.
Summary of Contents for EHGT17D-YM9ED
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