Description
The Johnson Controls A28MA-1 2-SPDT is an electromechanical temperature control in two stages for HVAC equipment, specifically cooling towers and evaporative condensers. It contains a remote sensor with a 6-foot capillary tube filled with some liquid that changes its volume with a change in temperature. This liquid expansion or contraction activates two separate switches (SPDT) housed within a weatherproof housing. The A28MA-1 can control two stages of cooling in your HVAC system by setting the desired temperature range of 40°F to 120°F. When the temperature goes high above the point set, the first switch is turned on to start the first stage of cooling.
