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Isolatable Timer Relay With Optional Keyswitch


SKU: 8d56e113eb9f Category: Brand:


This product is designed to meet the varied and demanding requirements of system integration and Isolation of auxiliary equipment for managing false alarms and system test purposes.

The main applications are:

Fire system alarm delays and temporary isolating of remote signaling (dialers etc) and Isolating unwanted plant shutdown during periodic system testing. Fire system interlinking in shopping complexes, where satellite systems may be connected together or connect to a larger main control system.

How it works

The unit accepts an alarm activation signal from a control panel and then triggers its onboard relay. The front RED LED indicates that the relay contacts have operated. The front YELLOW LED Indicates isolation/timing and an internal engineer LED indicates the timer setting in minutes (only viewable when cover is removed).

Turning the keyswitch to the ISO position will STOP the output relay from operating under any circumstances, however a warning YELLOW LED (slow pulse) and buzzer informs the user of this (also the keyswitch cannot be removed in the ISO position). The buzzer can be totally silenced by the DIL Switch settings but the disabled YELLOW LED cannot be inhibited.

To manage false alarms, an adjustable TIMER is provided (0 to 5mins) which delays the signal received from the fire panel. This will give some time for a responsible person to investigate an alarm before a telephone based digital communicator alerts the call centre. The unit produces a tick/tock noise and fast flashes the YELLOW LED when counting down to alarm. The internal engineer LED pulses indicate the time in minutes. At the end of the timer period the output will activate (the timer indicators will stop and the RED LED will also come on).

The ANTI-LATCH (DIL Switch selectable feature) works by switching the output relay off after 5 seconds, so the relay will activate as it would normally, but will ‘drop out’ after 5 seconds. This is primarily used to trigger latching fire zones/inputs and avoid system latch-up problems when resetting the system.

Trigger Signals

The unit can be triggered by two methods;

  1. Provide a 17 to 30V supply voltage and a switched to negative signal (via clean contacts or open collector o/ps)
  2. A normal fire system bell signal (2 core bell +/- circuit)

Method 2 allows ease of use in systems where access to the existing bell circuit is all that is possible. Because no power is available, the isolate warning buzzer only works when the bell circuit is active. When using method 2, short out the GND/SW Neg connection terminals with a link wire.


  • Flexible triggering – Switched Negative trigger or two wire only bell trigger.
  • Buzzer (adjustable) indicates the Isolated state or timer operating.
  • LED condition indicator.
  • Keyswitch to restrict Isolate function.
  • Built in adjustable Timer.
  • DIL Switch selectable – ‘pulse at timeout’ feature to stop interlink system latchups.


  • Input Voltage Range : 17 – 32V DC
  • Quiescent Current :
  • Alarm Current :
  • Timer : 0 to 5 mins ( in 1 min steps) +/- 5 seconds
  • Buzzer Volume : ~70dB(A)@1M (750Hz)
  • Output Contact Rating : Double Pole – Change Over Contacts 230V AC 8A max
  • Buzzer Speed Fast : every 3 seconds
  • Buzzer Speed Slow : every 30 seconds
  • Timer tick buzzer : 2 per second (approx.)
  • Anti-latch time before dropout : 5 seconds
  • Housing Size : Single gang : W.86 x L.86 x H.56.5 mm


If the key is in the ON position and I am using the timer is my trigger signal just delayed?

Yes the output relay operates but with a delay.

If the key is in the ISO position will the relay operate?

No the unit is isolated completely when the key is in the ISO position.

What stops me leaving the unit in the ISO position?

The are 3 things; Flashing Yellow LED, Buzzer and the key cannot be removed in the ISO position.

Can I just run it off a normal bell circuit?

Yes but there is no power when the bell circuit is not active. This means that the buzzer and LED will only function when the bell circuit is active.

Additional information

Weight 0.25 kg

Yes, No