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iNSTALLATiON
maintenance
12. Maintenance
WARNING Electrocution
Carry out all electrical connection and installation work
in accordance with relevant regulations. Before any work
on the appliance, disconnect all poles of the appliance
from the mains power supply.
If you need to drain the appliance, observe chapter "Maintenance /
Draining the appliance".
12.1 Draining the appliance
WARNING Burns
Hot water may escape during draining.
Note
Draining must be carried out in compliance with the ap-
plicable building regulations.
If the appliance needs to be drained for maintenance or to protect
the whole installation from frost, proceed as follows:
f Close the shut-off valve in the cold water supply line.
f Open the hot water tap.
f Open the drain on the bottom of the DHW cylinder with a
6 mm Allen key.
The appliance empties.
f To speed up the draining process, you can open the tempera-
ture and pressure limiter.
f To guide the water into a drain, a washbasin or similar, you
can fit a ø18 mm hose to the lower drain valve.
12.2 Flushing the system
If the system requires flushing, allow at least 50 l of water to run
from the DHW cylinder at the greatest possible flow rate.
f Close the hot water taps. Follow the instructions in chapter
"Maintenance / Draining the appliance".
12.3 Resetting the safety cut-off switch
The following may cause the safety cut-off switch to be triggered.
- Incorrect wiring.
- The temperature controller of the threaded immersion heater
or DHW cylinder is not working properly.
f Always disconnect the power supply to the appliance prior
to removing the control panel cover and resetting the safety
cut-off switch or changing the temperature controller setting.
f Reduce the temperature controller setting and press the
reset button. After adjusting the setting, make sure the cover
of the control panel is correctly positioned again and the
locking screw has been fitted.
f If operating the appliance is still not possible, contact a qual-
ified contractor.
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12.4 Troubleshooting: Intermittent or slow water
discharge from tundish
f Switch off the power supply to the threaded immersion
heaters.
f Turn the cold water supply valve to close it.
f Open a hot water tap.
f Turn the dial on temperature and pressure limiter (C) to the
left. Hold it in this position for 30 seconds.
f Check the pre-charge pressure in the expansion vessel and
adjust the pressure if required.
f Open the cold water supply valve.
f When water flows through the open hot water tap, close the
tap.
f Switch on the power supply to the threaded immersion
heaters.
12.5 Pre-charge pressure of the expansion vessel
Note
The expansion vessel requires annual servicing and may
not be altered or converted.
If water is discharged intermittently or slowly from the tundish
during heating, the appliance needs to be serviced by a qualified
contractor and the pre-charge pressure must be restored to the
original value.
f The expansion vessel must be fully drained in order to check
the pre-charge pressure. If the pressure deviates from the
value indicated on the label, it must be restored to the origi-
nal value.
f Never remove the expansion vessel without lowering the
pressure in the DHW cylinder and draining 10-20 l water via
the drain valve in the bottom of the DHW cylinder.
12.6 Regular maintenance work
Note
In areas with corrosive water, failure to observe the main-
tenance instructions for the threaded immersion heater
can cause the threaded immersion heater to separate
from the DHW cylinder, with subsequent water leakage.
The following maintenance work must be performed annually by
a qualified contractor:
f Check the temperature and pressure limiter and the expan-
sion valve.
f Operate each valve manually by turning the operating cap.
f Check that water can flow unimpeded through the tundish to
the outlet point.
f Make sure that the expansion valve and the temperature and
pressure limiter close correctly.
f Carry out a visual examination of the expansion vessel.
f If the pressure is below 0.3 MPa, top it up with a suitable air
pressure pump until it reaches the pressure value indicated
on the vessel's label.
f Remove, clean and replace the pipe strainer.
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Troubleshooting
