Annual Servicing; Hydraulic Unit; Cleaning The Filters; Dismounting The Water-Water Heat Exchanger - Baxi DUO-TEC COMPACT+ Gebrauchsanleitung Für Den Benutzer Und Installateur

19. ANNUAL SERVICING

If the boiler was operating, wait for the combustion chamber and pipes to cool down.
Before commencing any maintenance operations, make sure the boiler is disconnected from the power supply. After servicing,
reset the original operating parameters of the boiler if they were changed.
Do not clean the boiler with abrasive, aggressive and/or easily flammable substances (such as petrol, acetone, etc.).
To optimise boiler efficiency, carry out the following annual controls:
• Check the appearance and airtightness of the gaskets of the gas and combustion circuits;
• Check the state and correct position of the ignition and flame-sensing electrodes;
• Check the state of the burner and make sure it is firmly fixed;
• Check for any impurities inside the combustion chamber. Use a vacuum cleaner to do this;
• Check the pressure of the heating system;
• Check the pressure of the expansion vessel;
• Check the fan works correctly;
• Make sure the flue and air ducts are unobstructed;
• Check for any impurities inside the siphon (for condensation boilers);
• Check the magnesium anode, where present, for boilers fitted with storage boilers.
It is advisable not to use the service cap at the base to empty and clean the siphon. Remove the siphon from inside the boiler
and clean it with a jet of water. Fill the siphon with clean water and put back in place, making sure that it is properly connected.

19.1 HYDRAULIC UNIT

For special areas, where the water is harder than 20 °F (1 °F = 10 mg calcium carbonate per litre of water), install, on the cold
water inlet, a polyphosphate dispenser or an equivalent treatment system, compliant with current regulations.

19.2 CLEANING THE FILTERS

The DHW and CH filters are housed inside removable cartridges (see figure in annex "SECTION" F at the end of this manual).
The CH cartridge is located on the CH return line (F) while the DHW cartridge is on the cold water inlet (E). To clean the filters,
proceed as described below:
• switch off the boiler;
• shut the DHW inlet valve;
• drain the water in the CH circuit by opening valve (A);
• remove the clip (1-E/F) from the filter as illustrated in the figure and take out the cartridge (2-E/F) containing the filter, taking
care not to apply excessive force;
• to extract the heating filter cartridge, first remove the 3-way valve motor (1-2G);
• eliminate any impurities and deposits from the filter;
• reposition the filter in the cartridge and put it back into its housing, securing it with the clip.
• The NTC DHW sensor is positioned in point (D).
Remove the scale from the seat and relative NTC sensor fitted on the DHW circuit (D).
When replacing and/or cleaning the O-rings on the hydraulic assembly, only use Molykote 111 as a lubricant, not oil or
grease.

19.3 DISMOUNTING THE WATER-WATER HEAT EXCHANGER

The stainless steel plate-type water-water heat exchanger is easily disassembled with a screwdriver (see figure in annex
"SECTION" F at the end of the manual ) by operating as described below:
• drain the system, just the boiler if possible, through the drain tap;
• drain the DHW system;
• remove the two screws at the front securing the water-water heat exchanger and pull it out (B).
To clean the exchanger and/or DHW circuit, use Cillit FFW-AL or Benckiser HF-AL.
Pay great attention when dismantling the individual parts of the hydraulic assembly. Do not use sharp tools, do not apply
excessive force when removing the fixing clip.
41 7220318.01 (1-05/15)