System Sensor Intelligent Air Duct Smoke Detector Housing Field Wiring, Wiring Instructions

NOTE: This procedure should only be used in an emergen- cy, and it is not intended as a permanent substitute for ordering the correct length tubes.

Step 5. Field Wiring

Wiring Installation Guidelines

All wiring must be installed in compliance with the Canadian Electrical Code and the local codes having juris- diction. Proper wire gauges should be used. The conduc- tors used to connect smoke detectors to control panels and accessory devices should be color-coded to prevent wiring mistakes. Improper connections can prevent a system from responding properly in the event of a fire.

For signal wiring, (the wiring between interconnected detectors or from detectors to auxiliary devices), it is rec- ommended that single-conductor wire be no smaller than 16 gauge (1.5 square mm), and that two- or three-conduc- tor wire be no smaller than 18 gauge (1.0 square mm). The last foot or so of conduit should be flexible steel 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 DH500 is designed for easy wiring. The housing pro- vides a terminal strip with clamping plates. Wiring con- nections are made by stripping approximately 1/2-inch of insulation from the end of the wire, sliding this bare end under the plate, and tightening the clamping plate screw.

Step 6. Install the Filters

Most duct installations are subject to dust accumulation. System filters remove a large percentage of this contami- nation, but cannot remove all of it. Dust inside the duct detector causes problems. First, very fine particles of dust can enter the detector sensing chamber and cause the unit to go into alarm. Second, the accumulation of dust and dirt necessitates a more frequent periodic cleaning schedule, which can result in substantial cost and/or down time.

Disposable sampling tube filters can greatly reduce the nuisance alarms caused by dust, and can also significantly extend the maintenance interval. To install the sampling tube filters, simply push the filter adapter into the exhaust tube, and then push the filter onto the adapter tube on the

left, as shown in Figure 6. Then install the other filter over the end of the inlet sampling tube.

CAUTION

Filters require periodic cleaning or replacement, depend- ing on the amount of dust and dirt accumulated. Visually inspect the filters at least quarterly; inspect them more often if the dust accumulation warrants it. Replacement filters can be ordered from System Sensor (exhaust tube/ intake tube filter P/N F36-05-00).

The filters do not substantially affect smoke performance under normal conditions. There is very little restriction of smoke entry even when up to 90% of the filter is clogged. Visual inspection is usually adequate to determine whether the filters should be replaced because such a high percent- age of contamination is required to affect performance.

However, if further testing is desired, a Dwyer Model 460 (or equivalent) Differential Pressure Gauge may be used. Simply compare the differential pressure readings with and without the filters attached. There should be little or no difference. If the difference exceeds 10%, replace the filters. In no case, however, should the pressure differential be less than 0.01 inches of water or greater than 1.2 inches of water.

Step 7. Perform Detector Check

7.1 Air Flow

1.To verify sufficient sampling of ducted air, use a manom- eter to measure the differential pressure created from air flow across the sampling tubes. The pressure should measure no less than 0.01 inches of water and no greater than 1.20 inches of water.

Figure 6. Sampling tube filter installation:

INLET SAMPLING TUBE

FOAM GASKET

SAMPLING TUBE MOUNTING SCREWS

DETECTOR BASE

EXHAUST

FILTER ADAPTER

DETECTOR HEAD

SAMPLING TUBE	H0294-00
FILTERS

D500-08-00 5 I56-512-07R