Setting The Hardness Of Blended Water - BWT Duo-DVGW 2 Einbau- Und Bedienungsanleitung

Example:
24°d Hardness of untreated water
- 8°d Hardness of blended water
——————————————————
= 16 °d Reduction in hardness of untreated water
16 °d x 8.2mg/l = 131.2 mg/l increase in the sodium content.
10 mg/l Sodium content of untreated water
+ 131.2 mg/l Increase in sodium content
+ 5 mg/l Increase due to metering
——————————————————
= 146.2 mg/l Sodium content of partially softened water.
Preparing the brine
All commercially available regenerative salts conforming to EN 973 can
be used (in loose or tablet form).
Unscrew the lid (7) of the salt/brine container (6) and remove. Fill the
regenerative to a filling height of 250–350 mm (see Technical specifica-
tions). The brine cavity automatically fills with water during the "disinfec-
tion" stage. Wait and then check that the automatic water refilling turns
off as soon as the water has risen above the sieve base. Pour in the
regenerative (always adding whole units) up to a maximum of 75–150
kg. Close the cover and lock it.
Note: Allow hours for the brine to form, unless large immediate water
consumption is expected (e.g. filling a swimming pool).
Duo 2 and 3 only
During installation, it is possible to initiate a water refilling process manu-
ally to supplement the automatic process. Do this by pressing the button
in recess D for 3 seconds. Filling will continue automatically.
D

Setting the hardness of blended water

For Duo 2 and 3, shut the adjusting spindles (14+15) by turning them in
a clockwise direction and then set the optimal blended water hardness of
8 °d (only use an AQUATEST hardness tester to set, check and correct
hardness), ensuring that each spindle is opened by the same amount.
For Duo 6 and 10, shut both adjusting spindles (14+15) by turning them
in a clockwise direction. Open the large spindle until the hardness of the
blended water equals approximately 8 °d. Fine adjust the hardness of
the blended water using the small spindle (black turning knob). The small
spindle should never be opened completely, since only untreated water
could be drawn via this opening in the case of limited water use. (Only
use an AQUATEST hardness tester to set, check and correct hardness.)
Drinking water regulations stipulate a sodium limit of 200 mg/l. This limit
has been set so low so that people on a low sodium diet can still drink
water from the unit and use it for cooking.
Calculating the sodium content of partially softened water
The sodium content increases by 8.2 mg/l if the hardness of untreated
water is decreased by 1 °d.
Hardness of untreated water – hardness of blended water x 8.2 mg/l =
increase in the sodium content.
Ask at the water works what the sodium content of untreated water is
(e.g. 10 mg/l).
Sodium content of untreated water + increase of sodium content (due
to softening) = sodium content of partially softened water.
Repeated dosage further increases the sodium content by approx. 5 mg/l.
Drinking water regulations stipulate a sodium limit of 200 mg/l. We
recommend setting the treated water to a hardness between 4 °d and 8
°d. If the mandatory sodium limit of 200 mg/l is exceeded, the blended
water hardness may have to be set at more than 8 °d.
The unit is now ready for use.
Handing over the unit to the operator
If there is a delay between the installation of the unit and handover to
the user, a manual regeneration must be performed. The operator must
be told how the unit works as well as how to operate and inspect it.
Ensure that the operator receives the installation and operating manual.
EN
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