The Sigma Si Hold Off Unit provides a reliable method to temporarily inhibit fire extinguishant release and is available with red or green actuators (BS 7273-1 recommends white with a red button). The unit is supplied in a single-gang surface-mount enclosure, and for flush mounting, the enclosure can be discarded to fit a standard UK single-gang electrical back box.
The unit features a durable, shrouded push button to prevent accidental operation and connects via a simple two-wire connection to Sigma XT, Sigma XT+, Syncro XT+, or Sigma Si status units. Each unit is equipped with normally open (NO) and normally closed (NC) contacts, making it compatible with both monitored and unmonitored systems.
Key Features
Shrouded push button to prevent inadvertent operation
Activation resistor included
Compatible with all Sigma XT and Sigma XT+ models
Robust steel surface-mount enclosure
Flush-mount collar available for installation flexibility