US 11,781,793 B2
Control systems and methods for preventing evaporator coil freeze
Rakesh Goel, Irving, TX (US); and Siddarth Rajan, Addison, TX (US)
Assigned to Lennox Industries Inc., Richardson, TX (US)
Filed by Lennox Industries Inc., Richardson, TX (US)
Filed on Dec. 16, 2020, as Appl. No. 17/123,702.
Prior Publication US 2022/0186996 A1, Jun. 16, 2022
Int. Cl. F25B 47/00 (2006.01); F24F 3/14 (2006.01)
CPC F25B 47/006 (2013.01) [F24F 3/14 (2013.01); F24F 2003/144 (2013.01); F25B 2339/02 (2013.01); F25B 2347/00 (2013.01); F25B 2600/21 (2013.01); F25B 2700/2117 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A method of preventing evaporator coil freeze in a heating, ventilation and air conditioning (HVAC) system, the method comprising, by a controller in the HVAC system, the controller configured for wireless communication and comprising a processor and a memory:
determining, via at least one sensor disposed on an evaporator coil in the HVAC system, a reference saturated suction temperature (SST), wherein determining the reference SST comprises determining a plurality of SSTs via a plurality of sensors disposed on the evaporator coil and determining a minimum SST of the plurality of SSTs, wherein the minimum SST is the reference SST;
determining, by the controller, whether the reference SST is below a minimum SST threshold;
responsive to a determination that the reference SST is below the minimum SST threshold, increasing, by the controller, a discharge air temperature (DAT) setpoint;
determining, by the controller, an adapted setpoint value using the reference SST; and
setting, by the controller, the DAT setpoint to the adapted setpoint value.