NOTE: Air currents inside the duct may cause excessive vibration. This vibration can slowly open the seal around the
tube and permit air to escape. To prevent this from occurring, a 3-inch floor flange, 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 necessary to span the duct width.
Use a 0.193-inch diameter (#11) drill and add the appropriate 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 jurisdiction
using the proper wire gauges. 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 usually
recommended that single-conductor wire be no smaller than 16 gauge (1.5 square mm), and that two- or three-
conductor 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 DHX-501 is designed for easy wiring. The housing provides a terminal strip with clamping plates. Wiring
connections 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.
The DHX-501 operates from 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 proper 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, dampers,
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.
3. The LEDs on the detector should latch on as should any accessories (PA400, RA400Z, RTS451/RTS451KEY),
and the alarm condition should be verified at the control panel. The control panel must be active for an alarm
to be initiated.
MOLDED RIB
TEST
MAGNET
PAINTED SIDE
TOWARD HOUSING
DUCT
DETECTOR
HOUSING
DETECTOR
HEAD
TWIST
COUNTERCLOCKWISE
TO REMOVE
DUCT
HOUSING
TWIST
CLOCKWISE
TO INSTALL
DETECTOR
HEAD
A78-1812-05
A78-1812-02
Figure 7. Testing Detector Alarm
Figure 8. Detector Head Removal
B. RTS451/RTS451KEY REMOTE TEST STATION
The RTS451/RTS451KEY Remote Test Station facilitates test of the alarm capability of the duct detector as indicated
in the RTS451/RTS451KEY manual. The DHX-501 duct detector cannot be reset by the RTS451/RTS451KEY. It must
be reset at the system control panel.
To install the RTS451/RTS451KEY test coil, connect the device as shown in Figure 9. Place the coil in the detector
housing with the arrow facing up and pointing toward the detector as in Figure 9. Attach the coil leads to the housing
terminals as shown; polarity is not important. Firmly screw the test coil mounting bracket in place over the test coil.
The wire run connecting the remote test station to the duct detector must be less than 25 ohms.
DETECTOR
HEAD
TEST COIL
A78-1994-01
Figure 9. RTS451/RTS451KEY Test Coil Installation
C. R59-18-00 CALIBRATED TEST CARD (photoelectronic units only)
The R59-18-00 test card may be used to test the detector heads.
1. Remove the duct housing cover.
2. Remove the detector head from the duct housing as shown in Figure 8.
3. Remove the detector head cover by placing a small-bladed screwdriver in the side slot (see Figure 10) of the
detector cover, twisting it slightly until the cover can be turned counterclockwise.
4. Carefully insert the detector head into the duct housing and wait 50 seconds for power up. Do not hold the swirl
chamber to twist the detector head.
5. Insert the NO ALARM end of the test card into the test slot and slide counterclockwise until it stops. The detector
should not alarm after 20 seconds.
6. Remove the test card and then insert the ALARM end into the test slot and slide it counterclockwise until it stops.
The LEDs should latch on within 20 seconds. Remove the card and reset the detector at the control panel.
N500-03-00
5
I56-456-07
N500-03-00
8
I56-456-07
