Contactors; Transformer; Immersion Thermostat - Lochinvar Commercial Electric Water Heaters Installation And Service Manual

The limit is reset by pushing the red reset button on the
limit. Operation of the limit control usually indicates a
major problem with the heating elements or temperature
control. Do not continue to push the reset multiple times.
The problem causing the reset to function must be found
and corrected to insure proper operation. The blanket of
fiberglass insulation must be replaced over the surface
thermostats and immersion heating elements before the
power is turned on and the heater is returned to service.

CONTACTORS

FIG. 9 Magnetic Contactor
When the immersion thermostat and contactor option is
provided, the power to the immersion electric heating
elements is switched by a definite purpose magnetic
contactor. The contactor is supplied with 120 VAC from the
control circuit when the immersion thermostat senses a
drop in stored water temperature below the desired set
point. A magnetic coil in the contactor is energized to
complete the electric circuit supplying power to the
immersion heating elements. When the thermostat is
satisfied, the contactor coil is de-energized and power to the
heating elements is turned off.
CONTROL CIRCUIT TRANSFORMER
FIG. 10 Control Circuit Transformer
When the immersion thermostat and contactor option is
provided, a transformer is used to reduce the line voltage to
120 VAC for internal control operation. The transformer is
fused on the primary side. The VA rating of the control
circuit transformer is based on the load of the various
components in the water heater control circuit.
IMMERSION THERMOSTAT(S)
FIG. 11 Immersion Thermostat
9