Electronic Heat Detectors
Models THD-7052 & THD-7053
70.03
Effective: January 2006
FEATURES
Approvals/Listing
US and Canadian UL Listed (cULus)
FM Approved
CSFM Approved
NYC MEA Accepted (pending)
Thermistor based Heat Detection
Nominal Sensitivity
THD-7052: 135
o
F (57
o
C) Fixed Temperature w/
15
o
F (8.3
o
C) per minute Rate-Of-Rise
THD-7053: 135
o
F (57
o
C) Fixed Temperature
Wide Range of Input Voltage 10.2 to 36.8 VDC
Low Current design
Dual Response LEDs allow 360-degree viewing
Trouble Indication
Low Profile Appearance using Surface Mount Technology
Electrically and Mechanically Compatible with all Fenwal
Smoke and Electronic Heat Detectors and Bases
Interchangeable 2-Wire and 4-Wire Bases
Universal Relay Modules
Non Polarized
Locking Feature for Vandal Resistance
EMI and RFI Resistant
DESCRIPTION
The Fenwal Models THD-7052 and THD-7053 are thermistor-
based electronic Heat Detectors with a 135
o
F (57
o
C) Fixed
Temperature set point. In addition, the Model THD-7052 has a
Rate-Of-Rise of temperature detection feature rated at 15
o
F (8.3
o
C)
per minute. Both detectors have advanced solid-state, low-voltage,
surface-mount circuitry and are designed for 2-Wire and 4-Wire
installation using the appropriate Detector base. The detectors
are designed for Open Area Protection (UL 521) and may be
installed in systems intended for Releasing Device Service through
use of a compatible Fire Alarm Control Panel
Two Red Light Emitting Diodes are located diametrically opposite
each other so as to allow 360-degree viewing. Both LEDs
continuously indicate the operating condition of the Detector. During
standby, the LEDs flash once every six seconds. During alarm,
both LEDs light steady at full brilliance. A double flash every six
seconds indicates a detector with a thermistor trouble. An optional
base is available to provide remote LED function. A unique gated
output circuit design provides improved stability and transient sup-
pression. Special signal processing techniques verify the presence
of smoke before the detector will alarm.
The detector head is installed into the base with a simple twist-
lock action. A locking feature is provided for vandal resistant se-
curity. Detector base options are available to. provide for auxiliary
test, indication and/or control functions
Optional bases are available for supplementary 2-wire or 4-wire
relay functions. The Model THD-705x Heat Detectors may be in-
terchanged with other Fenwal Series CPD-705X Ionization and
Series PSD-715X Photoelectric Smoke Detectors when using
multifunction base configuration.
TECHNICAL SPECIFICATIONS
Table 2 lists the Technical Specifications for Models THD-7052
and THD-7053 Heat Detectors.
CONTROL UNITS
The Models THD-7052 and THD-7053 Detectors are designed
for operation with control units and releasing devices having spe-
cific voltage and current characteristics that are compatible with
the detector circuitry. The Detectors are compatible with the
Fenwal control units and interface modules listed in Table 1.
Please refer Fenwal Document 70.63 for UL Compatibility List-
ings with Fire Alarm Panels manufactured by others.
DETECTOR BASE OPTIONS
The Models THD-7052 and THD-7053 Detectors can be used
with the detector base options and accessories in Tables 3 and
4. Various base options are available to provide auxiliary relay
and/or remote indication and remote test feature.
SPACING (OPEN AREA LOCATION)
For UL/ULC applications, the Model THD-7052 and THD-7053
Detectors are listed to be installed on 70 foot (21.3 m) centers,
typically on smooth ceilings up to 15 feet (4.6 m) high and will
operate with minimum air circulation. Resultant maximum 4,900
square foot (455.2 m
2
) spacing may be used as a reasonable
guide for comparable applications.
For FM applications, the listed spacing is 35 feet (10.7 m) cen-
ters. Where special conditions exist (ceiling obstructions, etc.),
reduced spacing must be used to achieve adequate protection.
For additional information, consult the Fenwal Automatic Fire De-
tection Application Engineering Manual MC-402, NFPA-72 and
the local Authority Having Jurisdiction.
