High Limit Controller
The high limit opens and turns off the burner when the
water temperature reaches the set point. The high limit
automatically resets after the water temperature drops
past the set point and through the 10°F (6°C) differential.
Low Limit and Circulator Controllers
On a temperature rise, with the adjustable differential at the
minimum setting of 10°F (°C), the burner circuit (R-B) breaks
and the circulator circuit (R-W) makes at the control set point.
On a temperature drop of 10° F (6°C) below the set point, the
R-B circuit makes and the R-W circuit breaks. See Fig. 22.
At any differential setting greater than 10°F (6°C), the R-B
make temperature and R-W break temperature will remain the
same (control setting minus 10°F (6°C). The R-B break and
R-W make temperature will be the set point temperature plus
the difference between the differential setting and 10°F (6°C).
EXAMPLE:Set point of 140°F (60°C) differential set at 25°F
(14°C). On a temperature rise, R-B will break and R-W will
make at 155°F (68°C). On a temperature fall, R-B will make
and R-W will break at 130°F (54°C).