Pressure Relief Valve; Pressure Gauge; Expansion Vessel - Vaillant ecoTEC SERIES Instructions For Installation And Servicing

3 General requirements
Total heating Total hardness at 20 l/kW
output for the smallest boiler heating
surface
kW mol/m
< 50 No requirement or < 3
> 50 to ≤ 200
2
> 200 to ≤ 600
1,5
> 600
0,02
1) with systems equipped with wall-hung boiler and systems with electric heating elements
2) of the specific system volume (nominal capacity in litres/heating output; in case of multiple boiler systems the lowest individual
heating output should be used)
These data only apply up to 3x the system volume for filling and top-up water. Once this triple system volume is exceeded, the
water will have to be treated exactly the same as in case of exceeding the limit values given in Table 3.6 (softening, desalination,
hardness stabilisation and desludging).
Table 3.5 Guidelines for the heating water: Water hardness
Heating water
Unit
qualities
Electric conductivity
µS/cm
at 25 °C
Appearance
pH-value at 25 °C
Oxygen mg/L
1) With aluminium and aluminium alloys, the ph value range is
restricted from 6.5 to 8.5.
Table 3.6 Guidelines for heating water: Salinity
Caution!
Aluminium corrosion resulting in leakages
caused by unsuitable heating water!
Unlike materials such as steel, cast iron or cop-
per, aluminium is reactive to alkalised heating
water (pH-value > 8,5) which results in signifi-
cant corrosion.
With aluminium, ensure that the pH value of
the heating water ranges between 6.5 up to a
maximum of 8.5.
Caution!
Risk of material damage if the heating water is
treated with unsuitable frost or corrosion pro-
tection agents!
Frost and corrosion protection agents may
cause changes in the seals, noises during heat-
ing and possibly subsequent damage.
Do not use any unsuitable frost or corrosion
protection agents.
16
2)
3
1)
Low-salt saline
< 100
100-1500
Free of sedimentary substances
1) 1)
8,2-10,0 8,2-10,0
< 0,1 < 0,02
Total hardness at > 20 l/kW
< 50 l/kW for the smallest boiler
2)
heating surface
mol/m3
2
1,5
0,02
0,02

3.10.3 Pressure relief valve

A pressure relief valve is provided with the boiler. This
safety device is required on all sealed C.H. systems and
is preset at 3 bar and provided with a 15 mm
compression connection for a discharge pipe, which
must be of no less than 15 mm in diameter. The pressure
relief valve must not be used for draining purposes.

3.10.4 Pressure gauge

This is factory fitted to the boiler and indicates the
primary circuit pressure to facilitate filling and testing.

3.10.5 Expansion vessel

ecoTEC boilers incorporate a 10 litre expansion vessel
which is suitable for a sealed heating system with a
maximum water content of 100 litres.
If the nominal capacity of the built in expansion vessel is
not sufficient for the heating system (for instance in
case of modernisation of old open systems) an
additional expansion vessel can be installed external to
the boiler. It should be fitted in the return pipe as close
as possible to the boiler in accordance with BS 5449:
Part 1.
Guidance on the sizing of an additional expansion vessel
is given in Table 3.7.
Instructions for installation and servicing ecoTEC 839592_12
Total hardness at > 50 l/kW
for the smallest boiler heating
2)
surface
3
mol/m
0,02
0,02
0,02
0,02