Carrier NSB-LDT4-PS-BB Guide

Specifications subject to change without notice.
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Catalog No. 11-808-639-01
Water Leak Detector
Installation and Troubleshooting
#26268 –02/28/2020
Overview
The Water Leak Detector is designed to sense the presence of water and alert a central monitoring system of the
potentially destructive situation. Upon water detection, an alarm relay changes state, and a local red LED illuminates.
The transmitter can be set for latching alarm or non-latching alarm with normally energized or de-energized operation.
An optional remote water sensor is available for small inaccessible locations such as AHU pans or under floor water
detection.
Figure 2:
Water Leak Detector (above) with
Remote Spot Sensor (right) and
10 ft. FEP cable
Part #NSB-LDT4-RS10-BB
Water Leak Detector (above) with
Water Rope Sensor (below)
Part #s:
Figure 1: NSB-LDT4-RR10-BB (10 ft. rope)
Water Leak Detector with NSB-LDT4-RR25-BB (25 ft. rope)
Internal Sensor Probe NSB-LDT4-RR50-BB (50 ft. rope)
Part #NSB-LDT4-PS-BB NSB-LDT4-RR100-BB (100 ft. rope)

Catalog No. 11-808-639-01
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Specifications subject to change without notice.
Water Leak Detector
Installation and Troubleshooting
#26268 –02/28/2020
Figure 3: Water Leak Detector with
Built-in Sensor and a 5 Amp Relay in
a System Diagram (Side View)
Figure 4: Water Leak Detector with
Remote Spot Sensor and a 5 Amp
Relay in a System Diagram (Side View)

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Specifications subject to change without notice.
Water Leak Detector
Installation and Troubleshooting
#26268 –02/28/2020
Specifications
Power 24VAC +/-10%
5 Amp Relays 4 VA max
Wiring Flex connector or liquid-tight fitting
Relays Up to 6 wires
Transmitter 2 wires for Power
Mounting Lays in the pan or attached with a pan
edge hook with screws
Sensor
Standard Single SS probe from bottom of BB with
adjustable depth screw from .063” to
.84”
Optional Remote spot water sensor with depth
screw with adjustable depth from
1/16” to l/2”
Optional Remote rope water sensor
Detects water over the full length at
depths >0.125”. NOTE 100 ft.
maximum including non-sensing
extension cable.
Detector Transmitter
AlarmContacts TwoSPDT,5A relayoutputs
SPDT, 30 VAC/DC max
Selectable as normally
Energized or De-energized
Indication 1 Green Power LED, 1 Red Alarm LED
Reset Action If latching, local push button or power
interrupt
Sensor Reaction Responds to presence of water within 5
seconds
Termination Terminal strip, 4-10 terminals, 12-24 AWG
Agency RoHS, UL94V-0, UV-rated in Enclosure
Set Up
BB Sensor Adjustable depth from .063” to
.84” (≈1/16th” default)
Remote Sensor Adjustable depth from .063” to
.84” (≈1/16th” default)
Latching Latching version - Stays
Jumper energized after water has dried up
Non-latching version (default) -
Alarm follows wet or dry surface
Supervision Supervised version (default) -
Jumper De-energized when in alarm.
NOTE Relay will drop out on loss
of power indicating a water
detection alarm.
Unsupervised version -
Energized when in alarm.
Enclosure Ratings
Transmitter BB Box, NEMA 4
Remote Spot Submersible, w/ FEP plenum-
Sensor rated, waterproof cable
Rope Sensor Plenum rated
Ambient
Transmitter (BB) -40 to 185ºF (-40 to 85ºC),
0 to 95%RH, Non-condensing
Remote Spot -40 to 185ºF (-40 to 85ºC),
Sensor 0 to 95%RH, Condensing
Rope Sensor 32 to 167ºF (0 to 75ºC),
0 to 95%RH, Non-condensing
Enclosure Materials
Transmitter (BB) Polycarbonate
Remote Sensor Aluminum bracket w/ ABS
plastic shell

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Catalog No. 11-808-639-01
Water Leak Detector
Installation and Troubleshooting
#26268 –02/28/2020
Detection depth
adjust screw
Mounting
Nut
Sensor Probe
Screw
Figure 5:
Leak Detector with Sensor in a BB Box
Pan edge
mounting
screws
Figure 6: Water Sensor Pan Rim Mounting
Firmly push down
on clean surface
Figure 7: Remote Water Sensor Tape Mount
Figure 8: Remote
Water Sensor
Floor Mount
Mounting
Place the transmitter in a location where a water leak is
likely to cause damage such as a cooling coil pan, a hot
water tank pan, under a sink, under an elevated floor, or in
a drop ceiling under pipes. The transmitter can be
independently mounted in a visible location by using a
remote water sensor and waterproof cable as shown in
Figure 4. Terminate the transmitter as shown in the
termination section.
1. Set the transmitter where water is most likely to be a
problem or in the collection pan under the water coil or
heater (Figure 5).
Alternatively, a water sensor or remote water sensor
can be attached to the pan edge with two set screws
(Figure 6). Do not over tighten or puncture the pan.
Alternatively, a remote water sensor can be attached
to the pan or floor with mounting tape (Figure 7).
Clean surface thoroughly before setting the sensor in
place and push sensor down firmly. Mount the
detector enclosure in a visible location within cable
length of the remote water sensor.
Alternatively, a remote water sensor can be attached
to the floor with screws (Figure 8). Mount the
detector enclosure in a more visible location within
cable length of the remote water sensor.
Alternatively, a rope water sensor can be laid on the
floor or under pipes as shown in Figures 10, 11, 12 &
13. Cable clamps can be used to secure the sensor
to the floor.
2. Adjust the depth screw on the sensor probe in the middle
of the open enclosure to the alarm depth (Figure 5). If
using a remote water sensor, adjust the depth screw as
shown in Figure 9. The rope sensor detects water 1/8” off
the floor and has no adjustment.
3. Run the cable to the transmitter location leaving enough
slack to terminate and allow for some repositioning as
needed. Use a strain relief on the entering cable so the
wires do not tug on the terminals directly.
4. Terminate and configure in accordance with the termination
section.
Installer-provided
mounting screws
1. Loosen wing nut.
2. Set the required depth of the
sensor probe screw using a #2
Phillips screwdriver.
3. Hold the sensor probe screw
stationary with the screwdriver.
4. Turn the wing nut down the probe
screw until it engages the plastic.
5. Tighten the wing nut 1/4 turn into
the plastic.
Figure 9:
Remote Water
Sensor Depth
Adjusting
Detection
depth adjust
screw
Reference probe
Detection
depth adjust
from 1/16” to
1/2” depth

Specifications subject to change without notice.
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Catalog No. 11-808-639-01
Water Leak Detector
Installation and Troubleshooting
#26268 –02/28/2020
Rope Sensor Mounting
Figure 11: Sub-floor Sensor Mounting
Figure 10: Hot Water Tank Pan Mounting
Figure 13: Horizontal Pipe Sensor Mounting
Figure 12: Vertical Pipe Sensor Mounting
The following combinations of sensors can be used:
1. Tworope sensors with a combined length of no
more than 100’.
2. Twospot sensors with a combined length of no
more than 75’.
3. One spot sensor with a maximum length of
25’ and one rope sensor of no more than 50’.
Note: Shielded or twisted pair wire cannot be
used to extend the sensor wires. This applies
to both the remote spot sensor as well as the
rope sensor.

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Specifications subject to change without notice.
Water Leak Detector
Installation and Troubleshooting
#26268 –02/28/2020
Wiring and Termination
Figure 14: Leak Detector Circuit Board
Terminal Description
A Water Sensor (No polarity to water
sensor cable)
B Water Sensor (No polarity to water
sensor cable)
NC2* Alarm Contact 2, Normally Closed to
C2 when De-energized
COM2 Alarm Contact 2, Common
NO2 Alarm Contact 2, Normally Open to
C2 when De-energized
NC1* Alarm Contact 1, Normally Closed to
C1 when De-energized
COM1 Alarm Contact 1, Common
NO1 Alarm Contact 1, Normally Open to
C1 when De-energized
GND/NEU Power supplyground/neutral
V+/HOT Power supply input 24VAC +/- 10%
*Not used for low current relay version, SPST, Form A
Sensitivity Adjustment for 10’ Remote Rope Sensor
The unit’s leak detection sensitivity is set at the Sensitivity Adjustment Potentiometer
factory. However, for the remote rope sensors, the
sensitivity may need to be adjusted in the field.
If you are using a 10-foot remote rope and it won’t
respond, rotate the sensitivity adjustment
potentiometer 5 turns counterclockwise.
If you are using a 100’ remote rope and it is too
sensitive, then rotate the sensitivity adjustment
potentiometer 5 turns clockwise.
Figure 15:
Leak Detector
Circuit Board

Catalog No. 11-808-639-01
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Specifications subject to change without notice.
Water Leak Detector
Installation and Troubleshooting
#26268 –02/28/2020
Set Up and Commissioning
Indication/Controls Description
Red LED LED illuminates when water is detected
Green LED LED illuminates when normal power is applied
Reset Button Resets latching alarm contact (only if water is no longer present)
Latching Relay Left side of J1 set to top two pins listed as “L”
Non-Latching Relay Left side of J1 set to bottom two pins listed as “N” (Default)
Supervised Relay*** Right side of J1 set to top two pins listed as “S” (Default)
Unsupervised Relay Right side of J1 set to bottom two pins listed as “U”
*** Supervised means the relay is energized when not in alarm and the relay de-energizes ona power failure or alarm.
1. After the unit is installed and wired, turn on the power. (24VAC +/-10%)
2. Check that the green LED is on. If it is not on, check the power source.
3. Dampen a cloth or sponge and touch both the sensor probe tip and the sensor base. An alarm should occur
within 5 seconds.
4. The red LED should illuminate and the relay(s) should de-energize, or energize if set up as unsupervised. (To
check relay status, measure the resistance at the relay contacts or monitor the status from the BAS screen.)
5. Remove the dampened rag or sponge to clear the alarm. If the unit is set up for a non-latching relay (J1 jumper
across the “N” pins), the red LED and relay(s) will energize, or de-energize if set up as an unsupervised relay. If the
unit is set up for a latching relay (J1 jumper across the “L” pins), the operator must push the reset switch on the
detector board or interrupt power to clear the alarm.
6. Check the depth of the sensor probe screw (see Mounting) to be sure it’s at the appropriate water depth for alarm.
Operation Sequence
When power is applied, the green LED will illuminate and the unit will start to detect for water at the sensor probe. When
there is no detection of water (normal condition), the relays are not in an alarm state and the red LED remains off. For
units set up in the unsupervised relay mode, the relays are de-energized. For units set up in the supervised relay mode
(default), the relays will be energized. (NOTE When there is a loss of power, a supervised relay will drop out indicating
a water detection alarm.)
Within 5 seconds of water detection, the relays go into an alarm state and the red LED illuminates. For units set up
in the unsupervised relay mode, the relays are energized. For units set up in the supervised relay mode (default), the
relays are de-energized.
If the unit is in non-latching or auto-reset (default) operation, then the alarm state will automatically reset when the water
has dried up. If the unit is in latching or manual-reset operation, then the unit will stay in an alarm state until the reset
button is pressed or power is cycled. If there is still water detected during a reset button push, the unit will not reset. If
there is still water detected after a power interrupt, the unit will initiate another alarm within 5 seconds.
Diagnostics
Possible Problem Possible Solution
Green LED not on Check for proper power to the unit (see Power spec on page 6).
Red LED not working 1. Check for proper power to the unit (see Power spec on page 6). or relay
not energizing 2. Check if water is touching the sensor probe and reference probe.
3.Adjust sensor probe depth.
4. For rope sensor units, check the sensitivity adjustment as described on page 4.
Unit will not reset 1. Check for the presence of water or debris touching the two sensor probes.
2. Be sure the sensor wires are not shorted.
3. If the L pins on J1 are shorted, push the reset button or cycle power.
4. For rope sensor units, check the sensitivity adjustment as described on page 4.

Catalog No. 11-808-639-01
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Specifications subject to change without notice.
Water Leak Detector
Installation and Troubleshooting
#26268 –02/28/2020
Maintenance
Check the water sensor probe once a year to be sure there is no dirt or debris collected around the probes. Dirt or debris
around the probes may cause nuisance alarms in moist situations. Change the service intervals depending on
environmental conditions. In very clean conditions the probe may never need maintenance. Rope sensor may be wiped
down with isopropyl alcohol, warm soapy water on a cotton cloth, or placed in a dishwasher.
Caution
This unit is not intended to be a safety device.