Baxi Potterton Solar - Manual (Page 16)

Potterton Solar - Solar Thermal Domestic Hot Water System 16
3.0 Commissioning of solar controller
3.1.9 Controller functions
The Potterton Solar differential temperature controller
contains many functions to regulate and monitor the
solar primary system. Including
- controller functions for heating the solar cylinder
- functions for system protection and system monitoring
- additional functions (other accessories may be required
to achieve these functions).
3.1.10 General controller functions
The controller collects the temperatures of various
measuring points and determines the right time to charge
the storage tank on account of programmed (additional)
functions and controller parameters.
3.1.11 Cylinder heating by solar primary system
Switching action can be adjusted through dTmax (dTon)
and dTmin (dToff), but dTon cannot be set lower than dT
off + 1K .The solar cylinder is heated by operating the
solar pump on output A1 up to the set maximum storage
temperature. Pump operation is allowed as long as the
collector panel temperature exceeds the cylinder
temperature by a set amount.
3.1.12 Systems with two storage cylinders
For systems with more than one storage cylinder (System
Types 1 and 2) the cylinder heating can be optimised
depending on the energy supply. Usually the cylinder with
lower priority will have a lower temperature than that
with the higher priority. Re-directing the energy to the
lower priority cylinder will lower the temperature in the
collector array.To “reinforce” the collector temperature
the heating of the lower priority cylinder will be
interrupted for a short while at fixed intervals. If the
heating criteria for the higher priority cylinder is fulfilled
then the lower priority cylinder will be heated.
The higher priority cylinder can be selected in the
“Basic Settings” menu point no. 10.
“Basic adjustment” “Programming”
--- Maximum temperature
--- dT max (dT on)
Switch-on temperature difference
--- dT min (dT off)
Switch-off temperature difference
Corresponding values in menu