User manual
D550-06-00  2  I56-1367-004R
For signal wiring (the wiring between interconnected sensors 
or modules), it  is  recommended that  the  wire be  no  smaller 
than 18 gauge (1.0 square mm). Wire sizes up to 12 gauge (2.5 
square mm) may be used with the base. For best system per-
formance, the power (+ and –) wires and the communication 
circuit wires should be twisted pair or shielded cable installed 
in  separate  grounded  conduit  to  protect  the  communication 
loop from electrical interference.
Make wire connections by stripping about 
3
⁄8” of insulation 
from  the  end  of  the  wire.  Then,  slide  the  bare  end  of  the 
wire  under  the  clamping  plate,  and  tighten  the  clamping 
plate screw. Do NOT loop the wire under the clamping plate 
(See Figure 3).
The zone wiring of the sensor base should be checked before 
the sensor heads are installed. Check the wiring for continuity 
and polarity in the base.
See the individual sensor manual for the maximum sensor in-
stallation temperature.
Wiring Instructions
NOTE:  External  supply  shown  in  normal  standby  configura-
tion in Figure 4 and 5.
The wiring  diagram for a  typical  2-wire  intelligent  system is 
shown in Figure 4 and 5 (the monitor module is supervising 
the external supply).
Testing
Sensors and bases must be tested after installation and as an inte-
gral part of periodic maintenance. Test the B501BHT as follows:
NOTE:  Before  testing,  notify  the  proper  authorities  that  the 
smoke sensor  system is undergoing maintenance  and,  there-
fore, will be temporarily out of service. Disable the system un-
dergoing maintenance to prevent unwanted alarms.
1.   If configured as in Figure 4 or 5, reverse the polarity of the 
external 24VDC supply. If configured as in Figure 5, turn 
on the Intelligent Relay Module. All B501BHT bases on the 
loop should sound in approximately 10 seconds.
2.   Latch the sensor LED on from the control panel. That unit’s 
B501BHT should sound in approximately 10 seconds.
NOTES: 
1.   There  is  approximately  a  10  second  delay  built  into  the 
B501BHT before sounding. This delay is present whether 
the control signal comes from the sensor or from the exter-
nal power supply polarity being reversed.
2.   During  automatic  testing  cycles,  the  horn  may  sound  if 
the  associated  sensor  is  left  in  the  test  mode with  LEDs 
latched on for more than 4 seconds. Therefore, it is neces-
sary to complete testing of each sensor within this 4-sec-
ond limit to prevent the horn from sounding.
Figure 1. Terminal layout:
Figure 2. Mounting:
MOUNT B501BHT
TO ELECTRICAL BOX
4 INCH SQUARE BOX
Figure 3:
C0471-00
C0472-00
C0473-00




