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Information regarding design and operation
Note
As contact protection, Viessmann stagnation coolers (see page 106)
are equipped with a plate without flow due to the anticipated high tem-
perature on the surface. When using commercially available radiators,
contact protection must be provided and the connections must be dif-
fusion-proof. All components must be able to withstand temperatures
of up to 180 °C.
Specification
Output at 75/65 °C in W
Stagnation cooler
– Type 21
– Type 33
Pre-cooling vessel
Expansion vessel
For layout, function and specification of the expansion vessel, see
chapter "Installation accessories".
The expansion vessel can be calculated once the steam spread has
been determined and any heat sinks that may be used have been
taken into consideration.
The required volume is determined by the following factors:
■ Expansion of the heat transfer medium in its liquid state
■ Liquid seal
■ Expected steam volume, taking account of the static head of the
system
■ Pre-charge pressure
V
= (V
+ V
+ V
+ V
)·Df
dev
col
dpipe
e
fv
V
Rated volume of the expansion vessel in l
dev
V
Liquid content of the collectors in l
col
V
Content of the pipework subject to steam loads in l
dpipe
(Calculated from the steam spread and the pipework content
per m pipe length)
To determine the system and steam volume in the pipework, the content per m of pipe must be taken into consideration.
Vitotrans 200, type WTT
Part no.
Contents
l
Copper pipe
Dim.
Contents
l/m pipe
Corrugated stainless
Dim.
steel pipe
Contents
l/m pipe
For the liquid content of the following components see the relevant
"Specification" chapter:
■ Collectors
■ Solar-Divicon and solar pump assembly
■ DHW cylinder and heating water buffer cylinder
Selection of the expansion vessel
The details in the following table are standard values. They allow quick
estimates at the design and calculation stage. These values must be
verified by appropriate calculations. The selection relates to system
hydraulics with a liquid "bag" (see page 152) and to the use of a 6-bar
safety valve.
VITOSOL
(cont.)
Cooling capacity during stagnation
in W
482
835
—
V
Increase in the volume of the heat transfer medium in its liquid
e
state in l
V
= V
e
V
System volume (content of the collectors, the heat ex-
a
changer and the pipework)
β
Expansion factor
β = 0.13 for Viessmann heat transfer medium from −20 to
120 °C
V
Liquid seal in the expansion vessel in l
fv
(4 % of the system volume, min. 3 l)
Df
Pressure factor
(p
+ 1): (p
e
p
Max. system pressure at the safety valve in bar (90 % of
e
the safety valve response pressure)
p
System pre-charge pressure
o
p
o
3003 453
3003 454
3003 455
4
9
12 × 1
15 × 1
18 × 1
DN 10
DN 13
DN 16
0.079
0.133
0.201
Note
Check the size of the expansion vessel on site.
Liquid content in l
964
1668
450
· β
a
− p
)
e
o
= 1 bar + 0.1 bar/m static head
3003 456
3003 457
3003 458
13
16
34
22 × 1
28 × 1.5
DN20
DN25
0.314
0.491
DN 16
0.25
1
2
12
18
3003 459
43
61
35 × 1.5
42 x 1.5
DN32
DN40
0.804
1.195
VIESMANN
153
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