Immergas MAGIS M4-30 Use And Installation page 123

Symptom 5: lacking space heating capacity with low outdoor temperatures.
POSSIBLE CAUSES
The backup heater is not on.
An excessive capacity of the heat pump is used to
heat the domestic hot water (this only applies for
systems with domestic hot water storage tank).
Symptom 6: heating mode cannot switch immediately to DHW mode.
POSSIBLE CAUSES
The tank volume is too small and the position of
the water temperature probe is not sufficiently
high.
Symptom 7: DHW mode cannot switch immediately to heating mode.
POSSIBLE CAUSES
Heat exchanger for space heating not large
enough.
The space heating load is small.
The disinfect function is enabled but without
TBH.
Manually activate the FAST DHW function,
after the hot water meets the requirements, the
heat pump is not able to switch to air condition-
ing mode in time when the air conditioner is
required.
When the room temperature is low, there is not
enough hot water.
DHW mode priority.
Symptom 8: the heat pump in DHW mode interrupts operation but the setpoint is not reached, space heating demands
heat but the unit remains in DHW mode.
POSSIBLE CAUSES
Exchange service of the tank coil not large
enough.
TBH not available.
CORRECTIVE ACTION
Check that the OTHER HEATING SOURCE/Indoor unit backup heater (IBH) is
enabled, Chap. 10.5 Field settings.
Check whether or not the thermal protection of the backup heater has tripped (Chap.
Check the parts for the indoor unit backup heater (IBH)).
Check whether the tank booster heater (TBH) is running. The indoor unit backup
heater (IBH) and the tank booster heater (TBH) cannot run simultaneously.
Check that t_DHWHP_MAX and t_DHWHP_RESTRICT are configured properly.
Make sure that DHW PRIORITY is disabled in the user interface.
Activate T4_TBH_ON in the FOR SERVICEMAN user interface to activate the
tank booster heater.
CORRECTIVE ACTION
Set dT1S5 at the maximum value and t_DHWHP_RESTRICT at the minimum value.
Set dT1SH at 2°C.
Enable the TBH, and the TBH should be controlled by the unit.
CORRECTIVE ACTION
Set t_DHWHP_MAX at the minimum value, the recommended value is 60 min.
If the circulation pump outside of the unit is not controlled by the unit, try to con-
nect it to the unit.
Add a 3-way valve at the fan coil inlet to guarantee
a sufficient water flow.
Normal, heating is not required.
Deactivate the disinfect function.
Add TBH or AHS for the DHW mode.
Manually deactivate the FAST DHW function.
Set T4DHWMIN, the recommended value is ≥ -5°C.
Set T4_TBH_ON, the recommended value is ≥ -5°C.
If there is an IBH connected to the unit, when the hydraulic module is faulty, the
indoor unit must operate in DHW mode until the water temperature reaches the
set temperature before switching to heating mode.
CORRECTIVE ACTION
The same solution as for Symptom 6.
The heat pump remains in DHW mode until t_DHWHP_MAX or the setpoint is
reached. Add TBH for the DHW mode.
TBH must be controlled by the unit.
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