Master Catalog 125 Temperature Controls Section A Product Bulletin A25 Issue Date 0418 © 2018 Johnson Controls 1 Code No. LIT-125120 A25 Series Manual Reset Limit Controls Application A25 warm air limit controls “lockout” on a temperature increase to the control set point. Manual reset is required to reclose the electrical circuit. The controls are normally located in return air, supply air or plenum and are designed to shut down fans, burners or operate dampers, when the temperature of the air becomes higher than the control setting. A typical application is to stop air conditioning or ventilating fans in the event of excessive return air temperature, as from a fire. The use of these controls with the standard stop setting of 125°F (52°C) conforms to NFPA No. 90A-1981. A25 controls may be used as a high limit control in the supply air duct or plenum where a “lockout” type control is desired or required by local code. Factory Mutual approved models have a concealed setting with a visible scale. (See Fig. 1.) Features • Trip-free reset lever. Contacts cannot be blocked in a closed position. • Pilot duty electrical rating for up to 600 volts allows direct control of high voltage motor starters, etc. Fig. 1 -- A25 Manual Reset Limit Control. (Top) A25AN, A25CN, (Bottom) A25AP, A25CP. • Enclosed, dust protected switch. SPDT models have an auxiliary contact for operation of a warning light or audible alarm of the same voltage as the control circuit. • Rod and tube sensing element gives maximum response, allows high maximum element temperature and reduces the probability of dirt build-up on the element. • Adjustable duct mounting flange allows for duct insulation and/or various element insertion depths into the airstream. • Wide temperature range allows use of control on many applications. Variable high limit stop may be job set by installer where 125°F (52°C) limit is not required. Specifications 2 A25 Product Bulletin Fig. 2 -- Interior view illustrating high temperature stop and enclosed switch. Note generous wiring space provided. General Description A rod and tube type sensing element actuates the switch contacts. Main contacts are normally closed and open when the temperature at the element rises to the dial set point. Contacts are reclosed only by operation of the reset lever. The reset lever is “trip-free” and cannot be used to block contacts in a closed position. The contacts on the SPDT models are color coded: main contacts (Red to Blue) open on temperature rise, auxiliary contacts (Red to Yellow) close on temperature rise. Repairs and Replacement Field repairs must not be made. For a replacement control, contact the nearest Johnson Controls wholesaler. Ordering Information To order, specify: 1. Product Number. 2. Limit stop setting required. Limit setting is set at 125°F (52°C), unless otherwise specified. Performance specifications appearing herein are nominal and are subject to accepted manufacturing tolerances and application variables. UL Guide No. MBPR File MP 640 CSA Class 4813 02 File LR948 A25AP, A25CP: Factory M Building Technologies & Solutions 507 E. Michigan Street, Milwaukee, WI 53202 ® Johnson Controls and PENN are registered trademarks of Johnson Controls in the United States of America and/or other countries. All other trademarks used herein are the property of their respective owners. © Copyright 2018 by Johnson Controls. All rights reserved. Next >