12357 Exc VAT

Certified to EN54-4/A2 by the LPCB and VdS the AST-5-230 PSU is a powerful 24V 3A switch mode/digital hybrid PSU that is suited for use with most aspirating smoke detectors.

The PSU contains a plastic cover on the PSU PCB which guards against touching live parts.

A single-pole volt free changeover relay that switches for any fault condition provides the facility for fault monitoring of the PSU and batteries.

The main PCB contains a status LED to aid in fault diagnosis.
  • 1 flash = Mains Failure.
  • 2 flashes = Battery Voltage Low.
  • 3 flashes = Battery Voltage Critical.
  • 4 flashes = Charger Failure.
  • 5 flashes = Charger OK (Battery is either actively charging, or in float charge).
  • 6 flashes = No Batteries Fitted (indicating DIP Switch 4 position).
  • 7 flashes = Battery Resistance Fault (Level set by DIP Switch 2 position).
  • 8 flashes = Output Over-Voltage.


The AST-5-230 complies with EN54-4/A2 and therefore must monitor battery resistance. The fault threshold is directly related to the ability of the battery to deliver the rated current to the load. For example, batteries stored uncharged for long periods, during shipment and/or distribution, degrade leading to increased internal resistance. If a degraded battery is fitted, a fault will be shown by the PSU as mandated by EN54-4/A2.


    404mm W x 404mm H x 110mm D


    2.5 Ah to 17 Ah. 12v x 2
    Approved 12V VRLA Battery: Yucel Y Series 7Ah - 17Ah.


      ASD Power Supply Unit 24v 3A
      12357 Exc VAT

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