Ariston NIMBUS COMPACT S NET Manual page 93

MAINTENANCE
Maintenance is an essential operation to insure safety, correct
working and duration of life of the appliance.
It must be carried out in accordance with the regulations in force.
It is requested to check periodically the pressure of the refrigerant
gas. Before proceeding with maintenance:
• Disconnect the power supply from the appliance
• Close the water taps of the heating circuit
IMPORTANT!
The minimum temperature value of the water in heating, for a cor-
rect functioning of the system, is 20 ° C. During the starting phase
of the machine, it is allowed to work with lower temperatures. If
the external temperature reaches a value below 12 ° C it is ne-
cessary to have a backup energy source. NEVER DISCONNECT
THE INTEGRATED RESISTIVE ELEMENTS FROM THE TERMINAL
BOARD
General remarks
It is necessary to perform at least once a year the following checks:
1. Visual control of the general state of the system.
2. Check for leakage of the hydraulic circuit and possible replace-
ment of the seals.
3. Tightness of the circuit of the refrigerant gas.
4. Check the functioning of the heating safety tools (thermostats).
5. Overall control of the functioning of the appliance.
6. Check the pressure on the heating circuit.
7. Check the pressure of the expansion vessel
8. Keep clean the front grille and the outdoor unit battery pack.
ATTENTION
Empty the components that may contain residual hot water befo-
re manipulating them.
Remove limestone deposits from the components, following the
instructions on the descaling agent used.
Do this in a ventilated room, wearing the necessary safety devices,
avoid mixing of chemical products and protecting the equipment
and surrounding objects.
Information for the user
Inform the user on how the installed appliances work.
In particular, provide the user with the instruction manual, infor-
ming him of the need to keep the booklet close to the appliance.
Also, inform the user of the need to proceed with the following
actions:
• Periodically check the water pressure
• Pressurize the system, when necessary providing an adequate
air purge
• Adjust the parameters setting and devices in order to obtain a
better functioning and a more economical management of the
system
• Subcontract, as provided by the rules, periodic maintenance
Antifreeze function
The system has a frost protection.
Frost protection of the external unit : the primary circulator of the
internal unit is switched on if the return water temperature to the
external unit is equal to or less than 7 ° C for more than two con-
secutive minutes. If the water temperature reaches and exceeds
8 ° C for more than two consecutive minutes, the pump is turned
off . In the case of return temperature probe failure, the function
refers to the values of the flow temperature probe.
In the case in which the antifreeze function of the external unit is
not sufficient, the frost protection of the internal unit will be au-
tomatically activated. Also in this case the primary circulator of the
internal unit is switched on if the return water temperature to the
external unit is less than or equal to 7 ° C for more than two con-
secutive minutes. If the water temperature reaches and exceeds
9 ° C for more than two consecutive minutes, the pump is turned
off . In the case of return temperature probe failure, the function
refers to the values of the flow temperature probe.
In case of the circulation of water provided by the main pump is
still not sufficient to ensure a frost protection, the system will au-
tomatically manage the ignition of the entire external unit and of
the electrical resistances .
HYDRAULIC CONNECTION
CAUTION!
For countries which have enacted European standard EN
1487, the overpressure device supplied with the applian-
ce (if present) is non-conforming. The regulatory device
must be calibrated to a maximum pressure of 0.7 MPa (7
bar) and include at least a cock, check valve and control,
safety valve and hydraulic load cutout.
Some countries may require the use of alternative safety devices,
as required by local law; the installer must check the suitability of
the safety device he tends to use. Do not install any shut-off devi-
ce (valve, cock, etc.) between the safety unit and the heater itself.
The appliance's drain outlet must be connected to a drain pipe of
diam ter at least equal to the of the outlet itself,
with a funnel to permit an airgap of at least 20 mm for visual
inspection to prevent damage or injury to persons, animals and
property when the device operates; the manufacturer is not liable
for any such consequences. Use a hose to connect the overpres-
sure device to the mains cold water supply; fit a cock if necessary.
Fit a drain pipe to handle circumstances in which the drain cock is
opened.
When installing the overpressure safety device, do not tighten it
fully down, and do not tamper with its settings. It is normal that
water drip from the overpressure safety device when the applian-
ce is heating. For this reason one must install a drain, open to the
air, with a continuously downwards sloping pipe, in an area not
subject to subzero temperatures. If the mains pressure is close
to the valve's setting, fit a pressure reducer as far away from the
appliance as possible. If you decide to install mixer units (taps or
shower), purge the pipes of any potentially damaging impurities
first.
The appliance must not be supplied with water of hardness less
than 12°F, nor with especially hard water (greater than 25°F);
we recommend installing a water softener, properly calibrated and
controlled - do not allow the residual hardness to fall below 15°F.
Before using the appliance, we recommend filling its tank with wa-
ter and draining it completely so as to remove any residual impu-
rities.
93 / GB