Specifications

General requirements
20 Instructions for installation and servicing ecoTEC 839592_13
3
b
Caution!
Risk of damage from aluminium corrosion
resulting in leakages caused by unsuitable
heating water!
Unlike materials such as steel, cast iron or
copper, aluminium is reactive to alkalised
heating water (pH-value > 8,5) which results in
significant corrosion.
> With aluminium, ensure that the pH value
of the heating water ranges between 6.5
up to a maximum of 8.5.
b
Caution!
Risk of damage if the heating water is
treated with unsuitable frost or corrosion
protection agents!
Frost and corrosion protection agents may
cause changes in the seals, noises during
heating and possibly subsequent damage.
> Do not use any unsuitable frost or corro-
sion protection agents.
3.10.3 Pressure relief valve
A pressure relief valve is provided with the boiler. This
saf
ety device is required on all sealed C.H. systems and
is preset at (3 bar) 0.3 MPa and provided with a 15 mm
c
ompression 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 cir
cuit pressure to facilitate filling and testing.
3.10.5 Expansion vessel
ecoTEC boilers incorporate a 10 litr
e 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.
Vessel Volume [L]
Initial system pressure (bar) MPa (1.0) 0.1 (1.5) 0.15
Pressure relief valve setting (bar) MPa (3.0) 0.3
Total water content of system litres
25 2.7 3.9
50 5.4 7.8
100 10.9 15.6
125 13.6 19.5
150 16.3 23.4
175 19.1 27.3
200 21.8 31.2
225 24.5 35.1
250 27.2 39.0
275 30.0 42.9
300 32.7 46.8
325 35.7 50.7
350 38.1 54.6
375 40.9 58.5
400 43.6 62.4
425 46.3 66.3
450 49.0 70.2
475 51.8 74.1
500 54.5 78.0
For system volumes other than those given
above, multiply the system volume by the
factor across
0.109 0.156
Table 3.7 Sizing o
f additional expansion vessel
3.11 Pump specifications
3.11.1 Circulating pump
only ecoTEC plus:
T
he circulating pump is included in the boiler. The residual
pump discharge height depending on the by-pass valve is
shown in Fig. 3.10.1 (ecoTEC plus) and 3.10.2 (ecoTEC plus
637 / 837).
The operating mode of the 2-step pump can be adjusted
below the diagnosis number “d.19”, see section 8.1.2.
400
300
200
100
0
0 200 400 600 800 1000 1200 1600
Lift
[
mbar
]
Volumeflow
[
l/h
]
1800
1400
2. Step1. Step
Fig. 3.10.1 Pump specifications ecoTEC plus
(except ecoTEC 637 and 837)