System Sensor DH500ACDC Modification Of Inlet Sampling Tubes, Field Wiring, Wiring Instructions

available at most plumbing supply houses, may be used. This flange/connector mounting technique makes the initial installation easier because a 1- inch to 1-1/4-inch hole may be drilled where the flange/connector will be used. It is easier to push the inlet tube through the larger hole.

Modification Of Inlet Sampling Tubes

There may be situations where duct widths are not as specified for the installation. In such cases, it is permissible to modify an inlet sampling tube that is longer than neces- sary to span the duct width.

Use a 0.193-inch diameter (#11) drill and add the appro- priate number of holes so that the total number of holes exposed to the air flow in the duct is 10 to 12. Space the additional holes as evenly as possible over the length of the tube.

Step 5. Field Wiring

Wiring Installation Guidelines

All wiring must be installed in compliance with the National Electrical Code and the local codes having juris- diction, using the proper wire size(s). The conductors used to connect smoke detectors to control panels and accessory devices should be color-coded to reduce the likelihood of wiring errors. 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 18 gauge. The duct detector terminals accommodate wire sizes up to 14 gauge. The last foot or so of conduit should be flexible steel conduit (available in electrical supply houses) which facilitates installation and puts less strain on the conduit holes in the housing. Solid conduit connec- tions 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 control panel being used before wiring the detector loop.

Wiring Instructions

The DH500ACDC is designed for easy wiring. The housing provides a terminal strip with clamping plates. Wiring con- nections are made by stripping approximately 3/8-inch of insulation from the end of the wire, sliding this bare end under the plate, and tightening the clamping plate screw.

The DH500ACDC is built for 120/240 VAC or 24 VAC/DC to operate auxiliary functions. See Figure 5A for operating and wiring details.

Notes on Jumper Wire J5 (See Figure 5A):

1.When the detector is used in a 4-wire application (relay circuit is being used to control fans, dampers, etc.), jumper wire J5, located between the two terminal strips on the printed circuit board, must be cut to insure power supply supervision.

2.When the detector is used in a 2-wire application (relay control is not being used for any control of fans, damp- ers, etc.), jumper wire J5 must be left in place.

120/240 VAC Operation

To complete the wiring for 110/120 VAC operation, connect the power supply wires to terminals 15 and 16 (see Figure 5A). If 220/240 VAC operation is preferred, connect the power supply wires to terminals 16 and 17.

24 VAC/DC Operation

To complete the wiring for 24 VAC or DC, connect the power supply wires to terminals 7 and 8. Polarity is not important.

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 alarm. Second, the accumulation of dust and dirt neces- sitates 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, insert the filter adapter into the exhaust tube and 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. Inspect the filters at least quarterly – more often if dust accumula- tion warrants it. Replacement filters can be ordered from Notifier. (Exhaust tube/intake tube filter P/N F36-05-00.)

Filters rarely have a significant effect on the behavior of smoke. As a result, even a filter that is as much as 90% clogged does not significantly affect the entry of smoke into the duct detector housing. Therefore, visual inspection is usually all that is necessary to determine if filters need replacement.

D500-07-00 5 I56-432-11R