I will assume yours is the A419, and it would be a dual function, but it has to be setup for heating on the inside (unless you install a toggle switch to the outside). I use a 2 degree offset . . It helps somewhat with the compressor trying to hold the temp perfect which leads to increased on/ off cycling. Correction
. . I use 0 degrees OFS on the ferment chamber and 2 degree Dif . . thought I'd better check to be sure!