Autocall Heat Detectors, 4255 Series

ULC Listed CSA Certified Automatic detection of fires Compact rugged construction Rate of rise and fixed temperature principles of operation Large area of protection for each unit ratings 3 A at 6 VAC to 125 VAC 1 A at 6 VDC to 28 VDC 0.3 A at 125 VDC series heat detectors are an ultra sensitive electric thermostat to automatically detect the excessive heat created by a fire compact simple designed units are rugged and unaffected by All metal parts are brass or aluminum and are mounted on durable mineral filled phenolic base No exposed metal parts carry Electrical contacts are all silver clad and of ample size line terminals and wire ways are provided in the base for easy and installation in either open wiring or concealed wiring systems versions are available Rate of rise and fixed temperature and fixed only and fixed temperature rate of rise and fixed temperature detector is a dual element employing two independent methods of detection rate of and fixed temperature rate of rise method detects fires that grow rapidly in intensity by responding to abnormally fast temperature increases The fixed method detects smoldering fires which build temperatures a high level at a slow rate by responding to a specific temperature temperature only fixed temperature only version is of the same size and style of as the rate of rise and fixed temperature version but the rate of rise element Initiating Peripherals Detectors 4255 Series 1 series heat detector detectors having the rate of rise principle of operation include an chamber a vent and a flexible diaphragm When the unit is heated air in the chamber expands The vent permits the chamber to and slowly release the expanded air If a fire occurs the air in chamber will expand more rapidly than it can be vented This causes diaphragm to close a set of silver contacts normally open to set off fire alarm The rate of rise heat detector restores itself to a normally contact position when the heat is dissipated or remains constant heat detectors also have fixed temperature principle of operation consists of a phosphor bronze spring held under tension by sprinkler fusible solder When the heat detector is heated to melting point of the solder the spring releases and closes the silver normally open setting off a fire alarm You can recognize heat that operate by a fixed temperature principle by a small hole the shell You need to replace units operated by the fixed temperature as you cannot reset them rate of rise and fixed temperature heat detectors are for the majority of locations Do not mount them in line with heater blowers directly over stoves and ovens and other heat units detectors are available in two fixed temperature ratings rated at 135 57.2 are suitable for most applications those at 200 93.3 are suitable whenever the temperature exceeds 37.7 but not 150 65.5 for extended periods of time 93.3 units are particularly useful in those installations which air conditioning Additional listings may be applicable contact your local Autocall product supplier for the latest status Rev 1 02 2021 Detectors 4255 Series selection 1 Product selection 57.2 rate of rise and fixed temperature 93.3 rate of rise and fixed temperature 57.2 fixed temperature 93.3 fixed temperature area protected m2 ft2 m x 15 m ft x 50 ft ft2 m2 m x 9 m ft x 30 ft Normally Open N O In most fires hazardous levels of smoke and toxic gases can build up before a heat detector would initiate an alarm In cases where life safety is factor the use of smoke detectors is recommended guidelines temperature conditions of heat detectors temperature changes schoolrooms and industrial where no equipment is which could cause a ceiling rate of rise of 15 temperature changes directly over stoves or in line with space heater where ceiling temperature have a rate of rise near or 15 9.44 for each 2 Application guidelines of operation temperature rating 37.8 or less to 150 to 65.6 and temperature 37.8 or less to 150 to 65.6 temperature 57.2 93.3 57.2 93.3 reference heat detectors on the ceilings of the areas to be protected Underwriters Laboratories of Canada allows a 50 ft 15 m centre to centre spacing units operating on the rate of rise and fixed temperature principles unit gives protection for a maximum of 2500 ft2 225 m2 of unrestricted floor and ceiling space with smooth ceilings up to 75 ft 20 m high For ceilings use 25 ft 7.5 m centres or even closer spacing additional units where coverage appears limited due to structural characteristics of the protected area 2 details 4255 series heat detectors 2021 Johnson Controls All rights reserved All specifications and other information shown were current as of document revision and are subject to change without notice listings may be applicable contact your local Autocall product supplier for the latest status Listings and approvals under Tyco Fire Security GmbH and the names listed in this material are marks and or registered marks Unauthorized use is strictly prohibited NFPA 72 and National Fire Alarm Code are registered of the National Fire Protection Association NFPA Rev 1 02 2021