Climatemaster JW3 Freeze protection

 ClimateMaster units are shipped with the JW3 freeze protection jumper on the circuit board in the unclipped position.

When performing a new installation for a closed-loop system utilizing antifreeze, it is necessary to clip this jumper. This action adjusts the FP1 (Freeze Protection 1) sensor limit from the default of 30 degrees F for open-loop/groundwater applications to the required 10 degrees F for low-temperature fluids.

Please ensure this step is completed during setup, as failure to clip the JW3 jumper in closed-loop configurations may result in nuisance lockouts.