Fuses And Fuse Blocks; Surface Thermostats - Lochinvar Commercial Electric Water Heaters Installation And Service Manual

A main power terminal block is provided for field
connection of the branch power supply to the electric water
heater. All internal power circuits to the immersion heating
elements are connected to the load side of the main
terminal block. The line side of the terminal block has
individual lug type connections properly sized for the
recommended copper field wire size.

FUSES AND FUSE BLOCKS

FIG. 7 Fuse Block with Power Circuit Fuses
The internal power circuits of a water heater with a current
draw in excess of 48 amps are fused for safety. Each power
circuit to an immersion element is fused at a maximum of
48 amps. Power circuits may be fused at lower current levels
as needed to balance current on three phase units. The
power circuit fuses are held by a spring loaded fuse block
rated for the voltage specified to operate the water heater.
When the immersion thermostat and contactor option is
provided, the control circuit is also fused on the primary
side of the control circuit transformer.

SURFACE THERMOSTATS

WITH HIGH LIMIT
FIG. 8 Surface Thermostat/High Limit
HAZARD OF ELECTRICAL SHOCK - Before
opening the electrical access panel to adjust the
thermostat or servicing the water heater, make sure
the electrical supply to the water heater is turned
"OFF". Failure to do this could result in death,
serious bodily injury or property damage.
The standard control system uses an individual surface
mounted snap action thermostat with high limit for each
heating element. The thermostat/high limit is mounted
firmly against the tank, directly above each heating element.
The surface thermostat has an adjustable temperature
setting that can be varied from 110°F (43.3˚C) up to 180°F
(82.2˚C) at the highest setting. Turn off all electrical power
to the water heater before attempting to adjust the
thermostats. The temperature setpoint adjustment is made
on each thermostat by using a screwdriver. All surface
thermostats may be set at the same temperature or they may
be set a 2° to 4°F (1˚ to 2˚C) apart to step the elements on in
stages. There is a blanket of fiberglass insulation installed
over the heating elements and surface thermostats. This
insulation must be removed before the thermostats can be
adjusted. Each thermostat has a plastic cover installed to
prevent accidental contact with power wires when adjusting
the set point. This cover has an opening to allow
temperature adjustment and resetting of the high limit.
The cover does not have to be removed. The high water
temperature limit control which is part of each thermostat
assembly contains a manual reset on high water
temperature.
8
WARNING: