The Johnson Controls A25CP-1C Air Temperature Control; ROD & Tube; 25/215F; MANUAL RESet; SPDT; CONSEALED SCALE; FM APPROVED; HIGH LIMIT
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.)
- 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 C
- 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.