7. Detailed Description
7.4Description of safety features
General cut-off
The heater, the compressor and the circulation pump can be switched off by a relay built into the unit. This general cut- off will be activated if a malfunction is detected by the safety sensors.
When the general cut-off switch is activated, the circulator can only be restarted after the cause of the indicated fault has been eliminated. The display will show when this has occur- red. The circulator can then be re-started by pressing the Reset key.
Protection against over-heating
A built-in temperature limit switch protects against uncon- trolled heating of the bath liquid by activating the general cut-off if this limit is exceeded. (This safety device is indepen- dent of the control temperature sensor that regulates the set working temperature.)
The temperature cut-off limit is set on the dial at the rear of the circulator. This has a range of 20 to 95 °C. You should select a cut-off limit that is 5 to 10 °C above the set working temperature. If the temperature rises above this limit, the general cut off is activated and the following error message is
down to below the cut-off limit, the following code is
The built-in temperature limit switch also senses low levels of coolant. If the liquid level falls and exposes the heating ele- ment, the temperature will rise above the temperature limit cut-off level and the general cut-off will be activated. Top up with coolant to remedy this situation.
The same two error messages shown above will be displayed.
Restart the unit by pressing 
.
(Regular topping up with the liquid coolant is recommended, See Section 4.1, Start-up.)
. After the bath liquid has cooled
.