For signal wiring, (the wiring between interconnected de- tectors or from detectors to auxiliary devices), it is usually recommended that single conductor wire be no smaller than 18 gauge. The duct smoke detector terminals accom- modate wire sizes up to 12 gauge. The last foot of conduit should be flexible conduit (available in electrical supply houses), which facilitates easier installation and puts less strain on the conduit holes in the housing. Solid conduit connections may be used if desired.
Smoke detectors and alarm system control panels have specifications for allowable loop resistance. Consult the control panel manufacturer’s specifications for the total loop resistance allowed for the particular model control panel being used before wiring the detector loop.
Wiring Instructions
The DH100 detectors are designed for easy wiring. The housing provides a terminal strip with clamping plates. Wiring connections are made by stripping about
The DH100 duct smoke detector is designed to operate with 12 or 24 VDC UL listed
[5.7] Perform Detector Check
1.Perform STANDBY AND TROUBLE TEST per Section [6.2.1].
2.Perform MAGNET TEST per Section [6.2.2.1]. The RTS451 test of Section [6.2.2.2] may substitute for this requirement.
3.Perform AIR FLOW TEST per Section [6.1.1].
4.Perform SMOKE RESPONSE TEST per Section [6.1.2].
5.Perform SENSITIVITY TEST per Section [6.2.3].
[5.8] Install The Cover
Install the cover using the four screws that are captured in the housing cover. Be certain filters are installed as speci- fied in Section [5.5]. Make sure that the cover fits into the base groove and that all gaskets are in their proper posi- tions. Tighten the four screws.
[6]Duct Smoke Detector Maintenance And Test Procedures
Test and maintain duct smoke detectors as recommended in NFPA 72. The tests contained in this manual were devised to assist main- tenance personnel in verification of proper detector operation.
Before conducting these tests, notify the proper authorities that the smoke detection system will be temporarily out of service. Disable the zone or system under test to prevent unwanted alarms.
[6.1] Smoke Entry Tests
[6.1.1] Air Flow
To verify sufficient sampling of ducted air, use a manometer to measure the differential pressure created from air flow across the sampling tubes. The pressure should measure no less than 0.03 inches of water and no greater than 1.4 inches of water. The air handler must be operating for this test.
[6.1.2] Smoke Response
To determine if smoke is capable of entering the sensing chamber, visually identify any obstructions. Plug the ex- haust and inlet tube holes to prevent ducted air from carry- ing smoke away from the detector head, then blow smoke such as cigarette, cotton wick, or punk directly at the head to cause an alarm. REMEMBER TO REMOVE THE PLUGS AFTER THIS TEST, OR THE DETECTOR WILL NOT FUNC- TION PROPERLY.
[6.1.3] Filter Replacement
The filters do not substantially affect smoke performance even when up to 90% of the filter is clogged. Quarterly vi- sual inspection usually suffices to determine whether the filters should be replaced because only a high percentage of contamination affects performance. If further testing is re- quired, compare differential pressure readings with and without the filters installed. If the difference exceeds 10% replace the filters. In no case should the pressure differen- tial fall below 0.03 inches of water.
[6.2] Standby, Alarm, And Sensitivity Tests [6.2.1] Standby And Trouble
Standby — Look for the presence of the flashing green LED through the transparent housing cover. The LED should flash approximately every 10 seconds.
Trouble — If the Green LED does not flash, then the de- tector lacks power (check wiring, panel, or power supply), the detector board is missing (replace), or the unit is defective (return for repair)
Test — The trouble condition can be caused inten- tionally to verify correct operation of the sys- tem. Remove the detector board to cause a trouble condition locally and at the system control panel.
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