Viessmann Vitodens 100-W Specifications page 19

Minimum clearances
700 mm to the front of the boiler and/or unvented cylinder.
Minimum clearances to the LHS or RHS are not required.
Electrical connections
Recommended cables and leads
NYM-J 3 × 2.5 mm
2
– mains power
2-core min. 0.75 mm
2
– Vitotrol 100, Type UTDB
– Outdoor temperature sensor
NYM-O 3 ×1.5 mm
2
– Vitotrol 100, Type RT
– Vitotrol 100, Typ UTA
Ensure the power supply complies with the requirements of your
local power supply utility and current IEEE wiring regulations.
The mains cable can be protected by a fuse with a maximum
rating of 16 A.
It is recommended to install an AC/DC-sensitive RCD (RCD class
B) for DC (fault) currents that can occur with energy-efficient
equipment.
Make the power supply (230 V~, 50 Hz) via a permanent
connection.
Connect the supply cables and accessories at the terminals inside
the boiler.
Chemical anti-corrosion agents
Corrosion is generally avoided in correctly installed and operated
sealed heating systems.
Chemical anti-corrosion agents should be avoided where possible.
Some manufacturers of plastic pipes recommend the use of
chemical additives. In such cases, only use anti-corrosion agents
offered by the heating trade that have been approved for boilers
with DHW heating via single-walled heat exchangers (plate heat
exchanger or DHW un-vented cylinder).
Plastic pipe work for radiators
It is recommended to install a temperature limiter to restrict the
maximum temperature of plastic pipes in heating circuits with
radiators.
Attic or loft heating installation
The installation of a low water indicator specified as compulsory by
BS EN 1282 is not required when installing the Vitodens in an attic
or loft.
Underfloor heating system (UFH)
For heating systems with plastic pipes, we recommend the use of
impermeable pipes to prevent the diffusion of oxygen through the
pipe walls.
A temperature limiter is to be installed into the flow of the
underfloor heating circuit to limit the maximum temperature.
Combined safety valve (heating circuit) and condensate
drain
A safety valve in accordance with CE directive is integrated in the
Vitodens (operating pressure 3 bar).
The condensate pipe is connected to the discharge pipe of
the safety valve. The condensate hose supplied meets the
temperature requirements that are part of the CE certification.
Connecting the condensate pipe internally to the domestic waste
water system, either directly or via a tundish or washing machine
trap, is recommended.
Water quality/Frost protection
Unsuitable fill and top-up water increases the level of deposits
and corrosion and may lead to boiler damage.
Regarding the quality and volume of heating water, incl. fill and
top-up water, observe the Building Regulations Part L.
Thoroughly flush the entire heating system prior to filling it
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with water.
Only use fill water of potable quality.
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Soften fill water with a hardness above 3.0 mol/m3 (300ppm),
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e.g. with the small softening system for heating water
An antifreeze additive suitable for heating systems can be mixed
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with the fill water. The antifreeze manufacturer must verify its
suitability, otherwise damage to gaskets and diaphragms may
occur, as well as noise during heating operation. Viessmann
accepts no liability for damage or consequential damage as a
result.
Expansion vessel
An 8 litre expansion vessel is integrated as standard in the
Vitodens boiler, which is suitable for sealed heating systems with
a maximum water content of up to 100 litres:
Pre-charge pressure 0,75 bar
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Content 8 litres
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Content CH water volume Vitodens
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– 19 kW 2.8 litres
– 26 kW 2.8 litres
– 35 kW 3.4 litres
The size of the expansion vessel is subject to the heating system
specification and should be checked in each case. If the integrated
expansion vessel is not sufficient for the system then a second
expansion vessel has to be used.
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