Baxi MULTIFIT Evacuated Tube Collector Kit Instructions page 37

© Baxi Heating UK Ltd 2011
14.0 Commissioning of solar controller
14.9 Controller functions
The Baxi Solarflo 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).
14.10 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.
14.11 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
(recommended 65° C). Pump operation is allowed as long as
the collector temperature exceeds the cylinder temperature
by the amount set in the programming menu.
Corresponding values in menu
"Programming"
Maximum temperature
dT max (dT on)
Switch-on temperature difference
dT min (dT off)
Switch-off temperature difference
14.12 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 Adjustment" menu point no. 10.
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