Water Unit; Cleaning/Replacing The Dhw Filter; 10.3.12 Removing Limescale - Baxi 800 Combi 2 Series Installation And Service Manual

10 Maintenance
Fig.72 Water unit parts
10.3.10

Water unit

Caution
Do not use tools to remove components from inside the water unit
(e.g. filter).
For certain user areas, where domestic water hardness values exceed
20 °F (200 mg of calcium carbonate per litre of water) it is
recommended to install a polyphosphate batcher or equivalent system
complying with the prevailing standards.
10.3.11

Cleaning/replacing the DHW filter

The domestic water filter is housed inside a suitable removable cartridge
positioned on the cold water inlet. Proceed as follows to clean:
1. Disconnect the power supply to the boiler;
2. Close the domestic water inlet cock;
3. Empty the water from the domestic water circuit by opening a user
cock;
4. Remove the hall sensor (1).
5. Unscrew the cartridge (2) containing the filter, taking care not to apply
excessive force;
6. Remove any impurities and deposits from the filter;
7. Check the filter and replace if necessary:
8. Fit the filter back inside the cartridge and reinsert it into its seat;
9. Fit the hall sensor (1)
Notice
If the O-rings in the water unit need to be replaced and/or cleaned,
do not use oil or grease as a lubricant, but only Molykote 111.

10.3.12 Removing limescale

The domestic water circuit can be cleaned after removing the water-water
heat exchanger from its seat, by unscrewing the two front screws (A).
For the cleaning operations, you must:
Disconnect the power supply to the boiler.
Cut off the gas supply to the boiler.
Close the heating system return and flow cocks.
Empty the water contained in the heating circuit by opening the cock (E).
Close the domestic water inlet cock.
Empty the DHW circuit by opening the lowest hot water outlet.
Remove the exchanger by unscrewing the two screws (A).
Clean the plate heat exchanger with a descaling product (e.g. formic or
citric acid with a pH value of around 3). After cleaning, rinse thoroughly
under running water.
To re-assemble, perform the above actions in reverse order.
Caution
The maximum tightening torque for the two fastening screws (A)
for the plate heat exchanger is 4 Nm.
For more information, see
Treatment of water circulating systems, page 23
800 Combi 2 67