30
To purge the exchanger and/or the DHW system we suggest the use of Cillit FFW-AL or Beckinser
HF-AL.
For specific areas where water hardness exceeds 20
°
F (1
°
F = 10 mg of calcium carbonate per one
litre of water) we recommend you install a polyphosphate metering device - complying with the
applicable regulations - in the cold water inlet pipework.
24. Cleaning the cold water
filter
(LUNA HT 280 - HT 330)
The boiler is equipped with a cold water filter placed on the hydraulic assembly. To clean it do the
following:
• drain the DHW system from water.
• unscrew the nut on the flow sensing assembly (Figure 19).
• pull out the flow sensing device and its filter.
• remove the impurities.
Important: in the event of replacements and/or cleaning of the O-rings on the hydraulic unit, do not
use oil or grease as lubricant but exclusively Molykote 111.
To ensure the boiler operates at peak efficiency, the following checks must be performed every year:
• check on the appearance and tightness of the gas and combustion circuit gaskets;
• check on the condition and position of the ignition and flame sensing electrodes (see section 19);
• check on the condition of the burner and its fixing to the aluminium flange;
• check for any dirt in the combustion chamber. Use a vacuum-cleaner for this cleaning operation,
• check that the gas valve is calibrated correctly (see section 16);
• check if the siphon is dirty;
• check on the central heating system pressure.
• check on the expansion vessel pressure.
25. Annual service
