Vaillant Solar System and auroSTOR unvented solar..., Start-Up, Maintenance And Troubleshooting Manual

Page: 28 / 69

35 Manual - Solar hot water systems 0020009607_02
5.3 Installation of the solar circuit piping
5.3.1 General instructions
The Vaillant solar system is a closed hydraulic system in
which heat can be transferred to the cylinders only by
means of heat exchangers due to the special heat
transfer fluid of the solar system.Observe the following
points to ensure perfect operation with maximum
energy utilisation:
• Bleed the system completely during start-up and
maintenance since air in the system has a considerable
effect on the efficiency.
• The pipe diameters should not be too large, otherwise
the the flow in the solar system will slow down,
reducing the efficiency.
• Lay all system components in such a way to ensure an
even flow at the required nominal flow rate.
• Provide sufficient thermal insulation of the pipes to
prevent excessive heat loss. Select weather and UV
resistant insulation which is “bird peck proof“
especially for pipes laid outside.
• Use hard solder only.
• Do not use any plastic pipes.
• Do not use any Teflon tape in the solar circuit.
• Use press fittings only if temperatures of up to 200 °C
are allowed by the manufacturer.
a Caution!
Earth the solar circuit!
The solar pipe work must be earthed in
accordance with the requirements of BS 7671
IEE Wiring Regulations. Wiring protection
should be provided if there is high risk of
lightning strikes. The electronics in the solar
system, heating system or in the house could
otherwise be destroyed if they were to be hit by
lightning. Connect the collectors to an existing
lightning protection on the house.
a Caution!
Risk of damage to the collectors due to
excessive pressure.
The installation of a motorised 2 port valve in
the pipes of the solar system is not allowed,
since the safety devices in the solar circuit
could be overridden by it.
5.3.2 Material
a Caution!
Risk of damage because of wrong piping
material!
Plastic pipes, such as PE pipes or similar, must
not be used because of the high temperatures
that solar fluid might reach.
• Use copper pipes preferably as solar circuit pipes. All
pipelines in the solar circuit must be hard soldered.
5.3.3 Laying of the solar circuit pipes
The right selection of the pipe diameters plays a
significant role in terms of maximum efficiency of the
solar system.
To keep the pressure loss in the solar circuit to a
minimum, the flow velocity in the copper pipe should not
be higher than 1.5 m/s.
A nominal flow of 0.66l/min and 0.4l/min per m
2 of net
collector surface in flat collectors and vacuum tube coll-
ectors respectively is required to achieve an optimum
rate of thermal transfer.
Another decisive criteria for the optimum operation of
your solar system is the right layout of the solar pump.
The pump must be able to deliver more than the
nominal flow rate at the specified operating pressure.
The selection of the required pump speed depends on
the installed system. Reference value for the pump
selection can be found in Section 6.2, Setting the flow
rate and pump.
5.3.4 Connection of the collectors to the solar
pump unit
Vaillant provides various flexible hose systems for the
connection of the collectors to the solar pump unit:
309647: Solar Flexpipe 2 in 1 DN 20 X 15 m
309644: Solar Flexpipe 2 in 1 DN 16 X 15 m
0020023066: single flex pipe DN 16 X 15 m
Instructions for the connection of these flexible hose
systems can be found in the corresponding installation
manual.
Fig. 5.10 Solar flex pipe
Fig. 5.11 Installation of flex pipes at the solar pump unit
Installation 5