Installation and Operating Instructions
BDC 102
1328BED001-10B-E
Status 01/07
- 10 -
9
R
E G U L AT O R F U N C T I O N S
Temperature difference control
The BDC 102 regulates the difference in
temperature between the collector and the
storage cylinder:
If the collector temperature is more than 7K
higher than that of the storage cylinder, the
pump is switched on.
If the collector temperature falls below the
value: storage cylinder + 3K, the pump is
switched off.
The pump is
always
switched off if the
storage cylinder temperature is higher than
the value set for TSPmax.
Sensor monitoring
The two temperature sensors and their
connecting cables are monitored for
interruption and short circuit. A defective
sensor is indicated by a flashing “Fault”
light. An incorrect sensor type is generally
also indicated as a “short circuit” or
“interruption”.
Monitoring of circulation
Whilst the system is operating, the control
unit checks (pump = “on”), whether, with the
pump switched on, the difference in
temperature between the collector and the
storage cylinder exceeds the amount of
60°C+7K for 30 minutes. If this occurs, a
fault – continuous red light – is displayed.
Pump block protection
If the solar thermal system is not in use due
for example, to continuous bad weather, the
solar circuit pump can “seize”. To prevent
this from happening, the control unit
switches the pump on for 30 seconds at 10-
day intervals.
Installation protection
If the collector temperature exceeds 120°C,
the control unit switches off the solar circuit
pump. The pump is switched on again at
105°C, equivalent to a hysteresis of 15K.
10 R
E C T I F I C AT I O N O F F AU L T S
There are basically two kinds of system
fault:
•
Faults that are recognised by the control
unit and which it can therefore indicate
•
Faults that cannot be indicated by the
control unit
10.1 Indicated faults (display):
These faults are indicated by means of the red “Fault” LED. The frequency with which a light
flashes within a space of a few seconds indicates a specific error number. The possible
corresponding error sources are listed in the following table:
