Simplex 4100ES — AS1668 Fan Start Failure

The display shows AS1668 Fan Start Failure and the amber Fault LED turns ON. The manuals print the message in this one wording. The LED is not lit directly by the panel: the panel controls the AS1668 module, and that module turns the amber Fault LED to ON.

The manuals summarise it as: Fan has been commanded to start but airflow is not confirmed — the amber Fault LED turns ON. In full, the 4100ES-S1 panel has sent the Multi-Point I/O the control that closes the relay which controls the fan to start, for example as the result of a manual start or an auto start, and the air flow sensor in the duct has not sent the panel an indication that the air flow is ON. The fault is raised after a programmable delay, to allow the fan to speed up.

• The panel sent the Multi-Point I/O a control to close the relay that controls the fan to start — the manuals give a manual start or an auto start as the examples of such a command.
• The air flow sensor in the duct did not send the panel an indication that the air flow is ON.
• The panel waited through a programmable delay, to allow the fan to speed up, and the air flow confirmation still had not arrived.

1. Establish how the fan was commanded to start — a manual start or an auto start, the two examples the manuals name for this sequence.
2. Confirm that the panel's control to close the fan-start relay was sent to the Multi-Point I/O; that relay is what controls the fan to start.
3. Check the air flow sensor in the duct: the fault means its indication that the air flow is ON never reached the panel.
4. Take the programmable delay into account — the panel allows the fan time to speed up before it declares the fault, so the air flow ON indication must arrive within that delay.

• Programmable delay before the fault is declared: it exists to allow the fan to speed up; the fault tables print no value for it.