Carrier 48HC*04–14 Service And Maintenance Instructions

28Return Air Smoke Detector Sensor withoutEconomizer: The sampling tube is located across thereturn air opening on the unit basepan. See Fig. 37. Theholes in the sampling tube face downward, into the returnair stream. The sampling tube is connected through tubingto the return air sensor that is mounted on a bracket highon the partition between return filter and controllerlocation. (This sensor is shipped in a flat--mountinglocation. Installation requires that this sensor be relocatedto its operating location and the tubing to the samplingtube be connected. See installation steps below.)*RA detector must be moved from shippingposition to operating position by installerRETURN AIR DETECTORSAMPLING TUBERETURN AIRDETECTOR MODULE(Shipping positionshown)*CONTROLLERMODULEC07307Fig. 37 -- Typical Return Air Smoke Detector LocationReturn Air Smoke Detector Sensor with Economizer:The sampling tube is inserted through the side plates ofthe economizer housing, placing it across the return airopening on the unit basepan. See Fig. 38. The holes in thesampling tube face downward, into the return air stream.The sampling tube is connected using tubing to the returnair sensor mounted on a bracket high on the partitionbetween return filter and controller location. The sensor isshipped in a flat--mounting location. Installation requiresthe sensor be relocated to its operating location and thetubing to the sampling tube be connected. See installationsteps below.RETURN AIRSAMPLING TUBEC08129Fig. 38 -- Return Air Sampling Tube LocationCompleting Installation of Return Air SmokeDetector:SAMPLE TUBESCREWSFLEXIBLE EXHAUST TUBESC12049Fig. 39 -- Return Air Smoke Detector ShippingPositionUse the following steps to complete the installation of theReturn Air Smoke Detector.1. Unscrew the two screws holding the Return AirSensor Detector plate. See Fig. 39. Save the screws.2. Remove the Return Air Smoke Sensor and its detectorplate.3. Rotate the detector plate so the sensor is facing out-wards and the sampling tube connection is on the bot-tom. See Fig. 40.4. Screw the sensor and detector plate into its operatingposition using screws from Step 1. Ensure thesampling tube connection is on the bottom and the ex-haust tube is on the top. See Fig. 40.5. Connect the flexible tube on the sampling inlet to thesampling tube on the basepan.6. For units with an economizer, the sampling tube isintegrated into the economizer housing butconnecting the flexible tubing to the sampling tube isthe same.RETURN AIR SENSOR(Operating Position Shown)C12050Fig. 40 -- Return Air Sensor Operating Position48HC