Install a water drain in the boiler room and a funnel-siphon for the safety
unit.
Fit a non-return valve to the domestic cold water circuit.
Install a dielectric union on the domestic cold water inlet.
Pressure reducer
If the supply pressure exceeds 80% of the safety valve or unit calibration
(e.g.: 0.55 MPa/5.5 bar for a safety unit calibrated to 0.7 MPa/7 bar), a
pressure reducer must be located upstream of the appliance.
Install the pressure reducer downstream of the water meter in such a way
as to ensure the same pressure in all of the system's pipes.
Domestic hot water circulation loop
To guarantee the availability of hot water as soon as the taps are turned
on, a circulation loop between the draw-off points and the recirculation
pipes in the domestic hot water tank can be installed. A non-return valve
must be included in this loop.
Run the domestic hot water circulation loop via the boiler control system or
an additional timer program to optimise energy consumption.
Measures to take to prevent hot water flow return
Fit a non-return valve to the domestic cold water circuit.
4.10 Filling the domestic hot water tank
Caution
Initial commissioning must be performed by a qualified
professional.
1. Flush the domestic water circuit and fill the tank through the cold
water inlet pipe.
2. Open a hot water tap.
3. Completely fill the domestic hot water tank via the cold water inlet
pipe, leaving the hot water tap open.
4. Close the hot water tap when the water flow is regular, without any
noises in the pipes.
5. Carefully vent all of the domestic hot water pipes by repeating steps 2
to 4 for each hot water tap.
Venting the domestic hot water tank and the mains network helps to
prevent noises and banging caused by trapped air moving through the
pipes during draw-off.
6. Vent the DHW tank exchanger circuit using the air vent provided for
this purpose.
7. Check the safety components (particularly the safety valve or safety
unit), referring to the instructions provided with those components.
Caution
During the heating process, a certain amount of water may
escape via the safety valve or unit because of the expansion of
the water. This phenomenon is perfectly normal and no steps
should be taken to prevent it.
4.10.1 Domestic water quality
In regions where the water is very hard (Th > 20 °fH (11 °dH)), we
recommend fitting a softener.
The water hardness must always be between 12 °fH (7 °dH) and 20 °fH
(11 °dH) to be capable of providing effective protection against corrosion.
The softener does not bring about a derogation from our warranty
provided that it is approved and set pursuant to the codes of practice and
the recommendations given in the instructions for the softener and is
regularly inspected and maintained.
4 Installation
18
AS 300–2E BC
7724479 - v03 - 07102019
