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Design information regarding installation
13.5 Thermal insulation
■ The thermal insulation material provided must withstand the oper-
ating temperatures to be expected and must be permanently pro-
tected against the influence of moisture. Some open pore insulation
material that can be subjected to high thermal loads cannot provide
reliable protection against moisture produced by condensation. The
high temperature versions of close-cell insulating hoses, on the other
hand, offer adequate protection against moisture, but have a loading
temperature of max. approx. 170 °C. However, the connections at
the collector can be subjected to temperatures up to 200 °C (flat-
plate collector); for vacuum tube collectors these temperatures can
be substantially higher. At temperatures of over 170 °C, the insula-
tion material becomes brittle. However, the brittle zone is limited to
a few millimetres directly at the pipe. This overload only occurs for
a short period and does not pose any further risk to other compo-
nents.
■ The thermal insulation of the solar lines routed outdoors must be
protected against pecking damage from birds and gnawing by small
animals, as well as against UV radiation. A cover protecting the
insulation against damage by small animals (e.g. metal sheath) gen-
erally also provides adequate UV protection.
13.6 Solar lines
■ Use stainless steel pipe or commercially available copper pipe and
bronze fittings.
■ Metal seals (conical or locking rings and compression fittings) are
suitable for solar lines. Should alternative seals be used, such as flat
gaskets, their manufacturer must give an assurance of their ade-
quate resistance to glycol, pressure and temperature.
■ Never use:
– Teflon (inadequate glycol resistance)
– Hemp connections (insufficiently gas-tight)
■ Generally, copper lines in solar circuits are brazed or joined by press
fittings. Soft solder could be weakened, particularly near the collec-
tors, due to the maximum temperatures that may occur there. Metal
seal connections, locking ring fittings or Viessmann plug-in connec-
tions with double O-rings are the most suitable.
■ All components to be used must be resistant to the heat transfer
medium.
Note
Fill solar thermal systems only with Viessmann "Tyfocor LS" heat
transfer medium.
VITOSOL
(cont.)
■ Take high temperature differentials in the solar circuit into consider-
ation when routing and securing pipes.
At pipe sections that may be subject to steam loads, temperature
differentials of up to 200 K can be expected, otherwise 120 K can be
expected.
18
16
14
12
10
8
6
4
2
0
0
50
Temperature differential in K
A 5 m pipe length
B 3 m pipe length
C 1 m pipe length
■ Route the solar connection lines through a suitable roof outlet (ven-
tilation tile).
A
B
C
100
150
200
VIESMANN
109
13
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