Fill And Top-Up Water - Bosch Condens 8300i W Installation And Maintenance Instructions Manual

5.7

Fill and top-up water

Water quality of the heating water
The quality of the fill and top-up water is an essential factor for increased
efficiency, functional reliability, long service life and for maintaining the
operational readiness of a heating system.
NOTICE
Unsuitable water, antifreeze or heating water additives can damage
the heat exchanger or cause a fault in the heat source or DHW
supply!
Unsuitable or contaminated water can lead to sludge formation,
corrosion or scaling. Unsuitable antifreeze or hot water additives
(inhibitors or anti-corrosion agents) can damage the heat source and
heating system.
▶ Flush the heating system prior to filling.
▶ Only fill the heating system with potable water.
▶ Do not use well water or groundwater.
▶ Treat the fill and top-up water according to the instructions in the
following section.
▶ Only use antifreeze approved by us.
▶ Only use a heating water additive, e.g. corrosion inhibitor, if the
manufacturer of the heating water additive certifies its suitability for
a heat source made of aluminium materials and for all other materials
in the heating system.
▶ Only use antifreeze and heating water additives according to
specifications of the manufacturer, e.g. with regard to the minimum
concentration.
▶ Follow the instructions of the manufacturer of the antifreeze and
heating water additive about regular checking and corrective
measures.
Heating system water
Unsuitable fill and top-up water in the heating system can result in the
heat exchanger scaling up and failing prematurely.
Hardness range
soft (≤ 8.4° dH)
medium (8.4 - 14° dH)
hard (≥ 14° dH)
Table 8
CAUTION
The type of fluid used in the combination boiler heating circuit is to
be of a non-toxic type.
Antifreeze
The document 6 720 841 872 contains a list of approved antifreezes.
You can use the document search on our website to display this. You will
find the address of the website on the back cover of these instructions.
Corrosion inhibitor
The following corrosion inhibitors are permitted:
Designation
Fernox
Sentinel
Table 9
Condens 8300i W – 6721841531 (2022/10)
Water treatment
not required
recommended
required
Concentration
see supplier information
see supplier information
Heating water additives
Heating water additives, e.g. corrosion inhibitors, are only required in
the case of constant oxygen ingress, which can not be prevented through
other means.
Sealants in the heating water can cause deposits in the heat exchanger.
We therefore advise against their use.
Measures for hard water
To protect against increased limescale and resulting service work:
Water hardness Action
range
≥ 15 °dH/25 °f/ ▶ Set the DHW temperature lower than
2.5 mmol/l (hard) 55 °C.
≥ 21 °dH/37 °f/ We recommend:
3.7 mmol/l (hard)
▶ Installing a water treatment system.
Table 10 Measures for hard water
Preconditions for installation
15