Vaillant MultiMatic 700/2, Product Training

Page: 81 / 112

multiMATIC 700/2
Notes
10/2015 77 Training 0020228700_00

the collector sensor is fitted in the immersion sleeve outside the collector

and the static pressure of the solar system is set relatively low.
In these operating phases the start-up of the solar circuit pump must be securely pre-
vented, as otherwise there could be pressure shocks in the system. Damage to the
solar circuit pump from excessive temperatures from the collectors is prevented. Also,
in many cases it is not possible for the pump to ensure the necessary circulation of the
solar fluid if a steam buffer is present.
Functional description:
If the temperature at the collector sensor exceeds the adjustable solar circuit protection
temperature, the collector pump remains switched off. If solar circuit protection is ac-
tive, this is shown on the controller's display as "Solar protection" (status info).
Only once the temperature has fallen below the solar circuit protection hysteresis (30K)
is the pump switch-on block removed and the usual switch-on conditions apply to re-
start the collector pump.
4.5.7.13 Solar cylinder 1 (VR 70 = 6, 12)
Prompt/setting Select Comment
Switch-on differential
2
– 25 K
Switch-off differential 1
– 20 K
Maximum temperature 0
– 99 °C
Cyl. temp.: Bottom Display in °C
Maximum temperature
A maximum limit for the solar cylinder temperature can be set to not only ensure max-
imum yield from the solar cylinder heating but also provide protection against scalding
and scaling. When the preset maximum temperature is exceeded, the collector pump
is switched off. Solar charging is only enabled again when the temperature at the sen-
sor falls below the following value:
0.1 * maximum temperature
– 1 K, but at least
1.5 K . (Example: Maximum temperature = 80 °C => 0.1 * 80 K
– 1 K = 7 K). The cylin-
der frost protection function is not affected. The frost protection function is enabled
when the cylinder temperature falls below 10 °C. The cylinder is then heated to
15 °C. In the "Off" operating mode, "> 10 °C" is shown on the display as the target val-
ue.