Thermo Technologies SMT 100 - Manual (Page 6)

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2.3.1 A ONE PUMP SYSTEM
In this configuration, when the tank temperature is below the set-point,
TT, the AUX. relay is energised, and when rises above TT, the AUX. relay
is de-energised (see SMT 100 Diagram).
1 Connect the output terminal of the AUX. relay to the auxiliary heater or to a
contactor (external relay) if the heater has a greater current rating than 3A.
This is illustrated in the diagram below:
2 Connect the pump cable to the PUMP terminals of the control unit.
3 Connect the “neutral” (N) of the auxiliary heater or contactor, to the supplied
neutral terminal block on the power board.
4 Connect the mains supply to the terminals marked MAINS.
5 Connect the earth to the pump and contactor (if applicable).
Replace the “top” section of the control unit, and then fasten using the two
side fixing screws. The unit is now ready to be powered up.
When < TT : = ON
When > TT : = OFF