Product Bulletin No. TB26.1SS
August 18, 2026

Summary:

• This issue impacts the models MIX-2351TIRAP, MIX-2351TIRAPA, MRI-2351TIRAP bearing date codes
  3023 to 6062 where both conditions below need to be true:
  o the detector is operating in CLIP protocol
  o the Fire Alarm Control Panel is configured to sound an alarm only for the thermal portion of the
  detector.
• Detectors operating in Advanced Protocol are not affected.
• Detectors connected to Fire Alarm Control Panels (FACPs) that are configured as multicriteria (smoke,
  thermal, IR) are not affected.
• See page two for the four-digit date code location on the product label.
  Issue: System Sensor has identified an issue with the MIX-2351TIRAP, MIX-2351TIRAPA, MRI-2351TIRAP model
  detectors when operating in CLIP protocol and when the Fire Alarm Control Panel is configured to sound an alarm only
  for the thermal portion of the detector. In this configuration, the detector may not properly communicate an alarm
  condition. The alarm will operate as expected for the photoelectric sensor.
  The issue impacts detector models noted above bearing date codes 3023 to 6062. Detectors not operating in CLIP
  protocol, not configured as described above, or not within the date code range are not affected.
  Action needed: The warranty return policy for Products listed above will be honored and Products with date codes
  listed above, when used in the configuration described above, should be replaced and returned through normal
  channels. The warranty return policy for the Products listed above will be honored and any unused inventory should
  be replaced and returned through normal channels.
  This Product bulletin should be communicated to the site coordinator of all potentially impacted installations.
  If you have any questions regarding this bulletin, please contact System Sensor Technical Support at 1-800-736-7672.
  We appreciate your business and continued support of System Sensor products