Honeywell F-BO-AFE70 Series Installation, Connection, Commissioning, Maintenance

Contents

Honeywell F-BO-AFE70 Series Installation, Connection, Commissioning, Maintenance Manual pdf 10 page image

Chapter 2 • Manner of operation of a Purging unit User Manual Series F-BO-AFE702 Manner of operation of a Purging unitTypical structure of a system, consisting of fire detection control panel, aspirating smoke detector,Purging unit, compressed-air supply and sampling pipe.Fig. 2: Depiction of the structure of a system with an Automatic Purging Unit F-BO-AFE70 as well asthe required components and connectionsA … Automatic Purging Unit F-BO-AFE70B … Compressed-air supplyC … Aspirating smoke detector; in the above diagram an ASD with one pipe is shown, note thatfor each pipe system a separate Purging unit is needed.D … Fire detection control panelE … Power supply line. Both the Purging unit as well as the ASD must be supplied with 24VDC.F … Transmission of the fault message of the ASD to the fire detection control panelG … Transmission of the fire alarm of the ASD to the fire detection control panel. The connectioncan be established – as shown in the figure above – by means of a conventional line or vialoop modules.H … The fire detection control panel actuates or activates the F-BO-AFE70I … Air filter (optional), which can be located before the Purging unit. As a result, on the onehand the Purging unit is protected against contamination, and on the other hand every Pur-ging process also cleans the filter. If this is not possible (for example, because the filter caseis not pressure-resistant), the filter must be located between the Purging unit and the aspir-ating smoke detector.J … Check valve2.1 GeneralAspirating smoke detectors use a low negative pressure to continuously sample air through aspira-tion holes of a sampling pipe that is laid in a room or building, and direct the air samples to a cent-ral measuring element (the evaluation unit) in order to examine the sample for various characterist-ics (e.g., the smoke concentration).Over the operating time, continuously aspirating the ambient medium through the relatively smallaspiration holes and a pipe network with a relatively small cross-sectional area leads to an accumu-lation of contaminations which can change the aspirated air flow and can even result in the meas-urement failing completely. In order to prevent this contamination, dirty pipe networks and filtersystems should be regularly cleaned („purged“) by means of compressed air.For this purpose, clean compressed air is manually or automatically led into the pipe networkand/or the filter system at intervals. In order to protect the evaluation unit of the aspirating smokedetector against damage caused by exposure to compressed air, in conventional Purging units first avalve isolates the evaluation unit from the pipe network, and then compressed air is led into thepipe network through a second valve that is connected to a T-piece.I56-4252-010D200-104-0010