71
7.7
Bypass in the Solar Circuit
In some cases, integrating a temperature-guided bypass in the solar
circuit is a good idea. This bypass is to prevent cooled-down water,
which remains in the lines after downtimes, from being pumped
through the warm storage tank and therefore cooling this at the start.
Protecting a plate heat exchanger against ice cold water is also easy
in this manner.
To enable this bypass function you need only one of the four
differential thermostat functions (chapter 5.2), one available input and
one available output (called Tx and Rx in the adjacent diagram).
Function: If the solar circuit pump, for example, does not switch on for
the first time until the morning then only the collector will have been
heated. In the pipelines, however, there is still cooled-down solar fluid.
To keep this away from the storage tank or plate heat exchanger the
3-way valve (Rx) does not activate the solar circuit until the
temperature in the storage tank feed line (Tx) is at the set difference
higher than that of the storage tank (T2) or plate heat exchanger (T3).
Implementation: Open the menu item 'Settings' -> 'Service' ->
'Functions' -> 'diff. thermostats' and activate an available diff.
thermostat (
--2sec OK -->
:
). Then under Settings enter the
desired switch-on and switch-off differential and also the terminal
positions of the temperature sensors (Tx and T2 or T3) and the 3-way
valve.
Min. temp input W and max. temp input C are not needed with this application and should therefore be
selected so that they are outside the expected temperature range.
T1
