Double Element, Simultaneous, 3 Phase - Bradford White M-2-50T6DS Service Manual

Sequence of Operation- Double Element, Simultaneous Operation, 3 Phase.
1
Line voltage is applied across terminals L1
& L3 of upper thermostat. Line voltage also
extends to terminal L1 of lower thermostat.
Also, line voltage is applied to terminal L3
of lower thermostat. ECO in both upper &
lower thermostat is closed, so there is
voltage at terminal L4 of both thermostats
and to one side of both upper & lower
elements.
2
Tank is cold therefore both thermostats
are closed at terminal T2 (calling for heat).
This completes the circuit through the
thermostats and allows current to flow
through the elements.
3
When either thermostat is satisfied, it will
open at terminal T2, interrupting current
flow through the corresponding element. As
both thermostats satisfy, the system will be
in stand-by mode waiting for the next call
for heat. Thermostats will operate
independent of the other.
10
SEQUENCE OF OPERATION
1
ECO
Closed
ECO
Closed
3
Thermostat open
at terminal T2
Thermostat open
at terminal T2
Page 10
2
Thermostat closed
at terminal T2
Thermostat closed
at terminal T2