Xylem EPR IM Electric heater-circulator unit EPR (obsolete) - Manual (Page 26)

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Instruction manual Laing Electric heater circulator unit
www.lainginc.com
Wiring schematics for load shedding device if only one
or two heating elements are to be controlled by the
load shedding device.
Operation of heating elements with a load shedding device
The control of the electric heater circulator unit is perfectly suited for operation
with a load shedding device.
Normally, utility companies will provide a load shedding device with a potential
free contact which is closed when electrical heating is permitted and open
when electrical heating is not permitted.
- If the load shedding device should not control all heating elements, the
switching contact RR of the load shedding device needs to be connected
to terminals 1 and  of the electric heater circulator unit. In this case, the
main power should be connected as described in the chapter “Power
Supply“.
In this case, the first heating element is always activated when heating
is required, and for the second and third heating element jumpers 6 and
7 control whether they are controlled by the load shedding device. If the
appropriate jumper is closed, the element heats always when heat is re-
quested. If it is open, the heating element only heats when in addition to
the heat request
the contact bet-
ween terminal 1
and  is closed.
In this way, it is
possible to control
one third or two
thirds of the total
heating power by
a load shedding
device.