Safety Instructions; Description Of Functions - BWT AQA therm HFB-1717 BA Installation And Operating Instructions Manual

These installation and operating instructions are for
the AQA therm HFB-1717 BA and the AQA therm
HES. Both units are available separately. This modu-
lar system guarantees optimum flexibility for all ins-
tallation situations. With both systems your heating
system can be installed with the following cartridges
in accordance with the relevant standards and can
be filled and refilled. The AQA therm HRC/hardness-
reducing cartridge only reduces the calcifying subs-
tances in the water. The AQA therm SRC/desalina-
tion cartridge reduces both calcifying and corrosive
substances in the water. In addition to these water
treatment procedures, installers must ensure that the
heating system is correctly planned, installed, com-
missioned and operated in accordance with the rele-
vant standards and BWT specifications.

1. Safety instructions

I. Refer to the installation instructions.
II. Use the device
- in accordance with the specifications
- in perfect operational conditions
- in full awareness of the safety procedures and
potential risks.
III. Please note that the device is intended for filling
and refilling heating systems. Any use outside
the scope of the manual shall be considered
non-compliance with the specifications.
IV. Note that all installation, commissioning, main-
tenance and adjustment work must only be car-
ried out by qualified personnel.
V. Immediately remedy any faults that may compro-
mise safety.
VI. Treated water has different corrosive chemical
parameters. In addition to these water treatment
procedures, installers must ensure that the hea-
ting system is correctly planned, installed, com-
missioned and operated in accordance with the
relevant standards and BWT specifications.
VII. If the drinking water is heated via the heating
system and category 4 or 5 liquids are present,
any components that come into contact with
such must be double-walled. Demineralised wa-
ter (AQA therm SRC) corresponds to category 2
pursuant to EN 1717 Annex B.

2. Description of functions

AQA therm HFB 1717 BA
The AQA therm HFB-1717 BA comprises a backflow
preventer, pressure reducer and shut-off ball valves
and is designed to provide a secure, standardised
6280_EBA AQA therm HFB_HES_HWG_313660-5.indd 15
connection between the heating system and the drin-
king water supply. The integrated backflow preventer
and pressure reducer must be used to connect the
heating system permanently to the drinking water
system, allowing the heating system to be refilled at
any time.
The BA-installed AQA therm HES, which is installed
immediately after the AQA therm HFB-1717, compri-
ses a water meter, a docking point for optional sof-
tening cartridges (AQA therm HRC) or desalination
cartridges (SRC), an integrated shut-off ball valve and
a distilled water filling point (warning: non-potable
water!). This is used for softening/desalination and
to register the flushing, filling and refilling volumes.
Function of the backflow preventer
(AQA therm HFB-1717 BA)
The backflow preventer is a back-up valve compliant
with DIN EN 1717 and prevents the back pressure,
backflow and return of polluted water into the supply
line, into external systems or other system compo-
nents. The backflow preventer is divided into three
chambers (inlet, intermediate and outlet pressure
chamber). If no water is drawn, the backflow preven-
ter remains in idle mode under operating pressure.
The inlet- and outlet-side backflow preventers and
the drain valve are closed. When water is drawn,
the backflow preventer is in the flow rate setting. The
inlet- and outlet-side backflow preventers are ope-
ned and the drain valve is closed. If the differential
pressure between the inlet pressure and intermediate
pressure chamber falls below 0.14 bar, the backflow
preventer moves into the isolated position (return).
The backflow preventer on the inlet side closes and
the drain valve opens.
Function of the pressure reducer
(AQA therm HFB-1717 BA)
The pressure reducer reduces the inlet-side pressure
(inlet pressure) at the required pressure on the outlet
side (outlet pressure). The pressure reducer operates
on the force-balance principle. The diaphragm force
pushes against the spring force of the control valve.
If the outlet pressure decreases when water is drawn,
and with it the diaphragm force, a stronger spring
force, then opens the valve. The outlet pressure conti-
nues to rise until a state of equilibrium is reached bet-
ween the diaphragm and spring force. Inlet pressure
has no effect on the control valve in the pressure re-
ducer. Pressure fluctuations on the inlet side do not af-
fect the outlet pressure (inlet pressure compensation).
The AQA therm HFB-1717 BA can be permanently
connected to the drinking water supply by a hose or
pipe in accordance with DIN EN 1717 (plastics and
EN
15
24.09.15 09:09