ARITERM SWEDEN AB
Installation, Operation and Maintenance - 2007.10.26- 7/12
WATER PIPING
Radiator system and expansion vessel
When the system is being fi lled, the shunt valve shall be open. Th
e shut-off valves (in
the heat exchanger package for instance) shall be open and the external circulation
pump be turned off . Bleed the system carefully while fi lling. When the installation has
been in service for a few days, it shall be bled and refi lled once again.
Determine the required expansion vessel volume as follows:
Open system: 5% of the heating system water volume.
Closed system: Select the volume of the vessel in accordance with the manufacturer’s
instructions.
In the following table, you will fi nd examples of suitable closed system expansion
vessels.
System volume
Opening pressure
Initial pressure
Vessel volume
(litre)* (bar) (bar) (litre)
70
˚
C 90
˚
C
300
1,5
0,5
18 35
500
1,5
0,5
35 80
1000
1,5
0,5
80 140
1500
1,5
0,5
80 140
2000
1,5
0,5
140 200
An open system with 500 litre water volume demands at least a 35 litre expansion vessel and a 1500 litre
system volume a 80 litre expansion vessel
* System volume = boiler storage tanks + piping radiator volume.
Water piping shall be carried out in accordance with current local and national hot
water and building regulations. Safety equipment shall be installed in accordance
with regulations in force. If a closed expansion vessel is used, an approved safety valve,
a pressure gauge, and a vent valve shall be fi tted. Th
e safety valve shall be fi tted just
above, but not directly on, the boiler in such a manner that the connection with the
boiler cannot be closed off . Th
e connecting line from the boiler to the safety valve must
rise uninterruptedly. Before the boiler is fi lled with water, the enclosed drain tap shall
be fi tted at the bottom of the front panel.
Hot water connections
Th
e hot water connections shall be carried out in accordance with the adjoining piping
diagram. If one of the heat exchanger copper tubes needs cutting, this must be done
with loosened connections to avoid that foreign particles enter the heat exchanger.
Connections
1. Expansion vessel
2. Safety valve
3. Vent valve
4. Feed line - radiator system
5. Return line - radiator system
6. Hot tap water
7. Cold tap water
8. Shunt valve
9. Circulation pump – radiator circuit
10. Mixing valve – hot water circuit
11. Flow switch
12. Strainer
ATTENTION! According to current regulations (Sweden), the mixing valve or equivalent regulating
device shall be adjusted so as to limit the temperature of the leaving hot water to a maximum of
65°C.
9
8
10
11
12
7
6
1
2
5
4
3
