Viessmann Vitocell 200 Cylinder Design, Installation, User & Servicing Instructions page 13

d) It is preferable for the discharge to be visible at both the tundish and the final point
of discharge but where this is not possible or practically difficult there should be
clear visibility at one or other of these locations. Examples of acceptable discharge
arrangements are:
1. Ideally below the fixed grating and above the water seal in a trapped gulley.
2. Downward discharges at a low level; i.e. up to 100mm above external surfaces
such as car parks, hard standings, grassed areas etc are acceptable providing
that where children play or otherwise come into contact with discharges, a
wire cage or similar guard is positioned to prevent contact whilst maintaining
visibility.
3. Discharges at a high level; e.g. into metal hopper and metal down pipe with the
end of the discharge pipe clearly visible (tundish visible or not) or onto a roof
capable of withstanding high temperature discharges of water and 3m from
any plastic guttering systems that would collect such discharges.
4. Where a single pipe serves a number of discharges, such as in blocks of flats,
the number served should be limited to not more than 6 systems so that any
installation can be traced reasonably easily. The single common discharge pipe
should be at least one pipe size larger than the largest individual discharge pipe
to be connected. If unvented hot water storage systems are installed where
discharges form safety devices may not be apparent i.e. in dwellings occupied by
blind, infirm or disabled people, consideration should be given to the installation
of an electronically operated device to warn when discharge takes place.
Safety
The safety devices supplied or fitted on an Viessmann Vitocell 200 Cylinder are selected
for their suitability for the temperatures and pressures involved. They must not be
changed, removed or by-passed and it is essential that only genuine replacement parts
supplied or approved by Viessmann Limited are used. This includes the immersion
heaters, which must incorporate an energy cut-out. All parts are available to approved
installers from Viessmann Limited.
Secondary
Return Circuit
P&T Relief Valve
Pump Non Return
Valve
Immersion Heater
Stop
Tap
Boiler
Flow
Kitchen
Boiler
Cold
Return
Tap
Schematic Diagram
Hot Outlet
Tundish
Expansion
To Drain
2 Port Valve
Page 13
iNSTALLATiON
Combination inlet Group
Combines elements 1, 2 and 3 below.
1. Pressure Reducing Valve - This must be fixed
near the cylinder. The cold water supply to
any mixer taps/showers must be taken from
the cold water tapping of this valve to ensure
balanced hot and cold pressures. This valve
is factory set to ensure the correct operating
pressure for the Viessmann Vitocell 200
Cylinder.
Balanced
Vessel
2. Non Return Valve - This is integral with the
Cold
Outlets
pressure reducing valve to prevent backflow
of hot water towards cold water draw off
ERV
NRV
points.
PRV
3. Cold Water Expansion Relief Valve - This safety
device is preset at the factory and will relieve
excess cold water pressure resulting from a
Combination
Valve
fault condition.