Technical Bulletin FLS Issue Date 0819 © 2019 Automation Components, Inc. 1 Part No. 24-7664-03817, Rev. - A/FLS Series Low Temperature Cutout Thermostat Line Voltage Application The A/FLS Series low temperature cutout thermostats have electrical contacts operated by a temperature sensing element. On the 4-wire, two-circuit models, the main load contacts (LINE-M2) open on a temperature drop and simultaneously the auxiliary or alarm contacts (LINE-M1) close. The thermostat is used as a low temperature cutout device on heating and cooling coils or other applications where there is a possibility of air being stratified. It responds only to the lowest temperature along any 14 to 16” (35 to 40 cm) length of the 6, 10, 20 or 50 foot (1.8, 3, 6, or 15 meter) long sensing element. The sensing element is usually located on the downstream side of the coil. When the temperature along any point of the sensing element reaches the set point, the thermostat will stop the fan. The outdoor damper is installed to close when the fan stops. The thermostats with manual reset will lock out when the sensed temperature drops below the set point. The reset must be pushed and released before the contacts can be reclosed. All A/FLS Series thermostats are designed for use only as operating controls. Where an operating control failure would result in personal injury and/or loss of property, it is the responsibility of the installer to add devices (safety, limit controls) that protect against, or systems (alarm, supervisory systems) that warn of control failure. Installation Mounting CAUTION: Locate the thermostat case and bellows where the ambient temperature is always warmer than the set point. The thermostat operates only from the lowest temperature along the entire 6, 10, 20, or 50 foot sensing element. Avoid sharp bends or kinks in the sensing elements. The thermostat may be mounted to a wall surface or panel board using the two mounting holes provided in the back of the case. The desired mounting position is with the element bellows pointing down. An optional mounting flange (ACI Part # FLS MTG BKT) can be ordered separately, if preferred. For accurate thermostat operation, the sensing element should be horizontally serpentined across the face of the coil to sense temperature in all areas. Specifications Type Number A/FLS-xx-A A70GA 4-Wire, 2-Circuit, Main (LINE-M2) Contacts, Open on Temperature Drop, Simultaneously Auxiliary Contacts Close A/FLS-xx-M A70HA 4-Wire, 2-Circuit, Main (LINE-M2) Contacts, Open on Temperature Drop, Simultaneously Auxiliary Contacts Close, Manual Reset Range 15 to 55oF (-9 to 13oC) with STOP at 35oF (1.7oC) Minimum Differential Approximately 5 o F (2.8 o C); Non-Adjustable Maximum Overrun Temperature at the Element 400oF (204oC) Element Vapor Pressure; 6, 10, 20, 50ft (1.8, 3, 6, 15m) Long Fig. 1 -- Electric thermostat shown with manual reset. 2 A/FLS Technical Bulletin Wiring WARNING: Disconnect the power supply before wiring connections are made to avoid possible electrical shock or damage to the equipment. Make all wiring connections using copper conductors only and in accordance with the National Electrical Code and all local regulations. For maximum electrical rating of the thermostat, see the label on the inside of the thermostat cover. Loads exceeding the rating of the thermostat can be handled with a relay or motor starter. CAUTION: Only use terminal screws furnished in the switch (8-32 × 1/4 in.). Longer terminal screws can interfere with the switch mechanism and damage the switch. Checkout Procedure The operating point of the thermostat should be confirmed by an accurate thermometer. Before leaving the installation, observe at least three complete operating cycles to be sure that all components are functioning correctly. Repairs and Replacement Field repairs must not be made. For a replacement thermostat, contact Automation Components, Inc. Single Point of Contact: Automation Components, Inc. 2305 Pleasant View Rd. Middleton, WI 53562 USA (888) 967-5224 www.workaci.com Pole Number LINE-M2 (Main) LINE-M1 (Auxiliary) Motor Rating 120V 208V 240V 277V 120V 208V 240V 277V AC Full Load Amp 16.0 9.2 8.0 - 6.0 3.3 3.0 - AC Locked Rotor Amp 96.0 55.2 48.0 - 36.0 19.8 18.0 - AC Non-Inductive Amp 16.0 9.2 8.0 7.2 6.0 6.0 6.0 6.0 Pilot Duty – Both Poles 125 VA, 120 to 600 VAC 57.5 VA, 120 to 300 VDC Next >