Formula To Calculate The Expansion Vessel Pre-Pressure; To Check The Water Volume And Flow Rate - Daikin Altherma 3 R F Installer's Reference Manual

8 | Piping installation

8.2.2 Formula to calculate the expansion vessel pre-pressure

8.2.3 To check the water volume and flow rate

Installer reference guide
80
g Cold water taps
h Hot water taps
i Shower
▪ Domestic hot water tank – Pressure relief valve. A pressure relief valve (part of
the inlet control group) with an opening pressure of 8 bar prevents excessive
water pressure in the water circuit.
▪ Domestic hot water tank – Pressure and temperature relief valve. The pressure
and temperature relief valve prevents excessive water pressure (≥10 bar) and
excessive water temperature (>95°C) in the domestic hot water tank.
▪ Thermostatic mixing valves. In accordance with the applicable legislation, it may
be necessary to install thermostatic mixing valves.
▪ Hygienic measures. The installation must be in compliance with the applicable
legislation and may require additional hygienic installation measures.
▪ Recirculation pump. In accordance with the applicable legislation, it may be
required to connect a recirculation pump in between the hot water end point
and the recirculation connection of the domestic hot water tank.
a b
a Recirculation connection
b Hot water connection
c Shower
d Recirculation pump
▪ Valve towards expansion vessel. The valve towards the expansion vessel (if
equipped) MUST be open.
The pre-pressure (Pg) of the vessel depends on the installation height difference
(H):
Pg=0.3+(H/10) (bar)
The indoor unit has an expansion vessel of 10 litre with a factory-set pre-pressure
of 1 bar.
To make sure that the unit operates properly:
▪ You must check the minimum and maximum water volume.
▪ You might need to adjust the pre-pressure of the expansion vessel.
Minimum water volume
There are no requirements for the minimum water volume.
INFORMATION
In critical processes, or in rooms with a high heat load, extra water might be
required.
c
d
ERGA04~08EAV3(A) + EHVH04+08SU18+23EA6V
Daikin Altherma 3 R F
4P629090-1 – 2020.08