Sequence Of Operation; Single Element Operation - Bradford White M-2-50T6DS Service Manual

Residential and light duty commercial electric water heaters are designed to operate using several different operating
modes. The common modes and sequence of operation are as follows:

1. Single Element Operation.

2. Double Element Non-Simultaneous Operation (single phase).
3. Double Element Non-Simultaneous Operation (3 phase).
4. Double Element Simultaneous Operation (single phase).
5. Double Element Simultaneous Operation (3 phase).
Sequence of Operation- Single Element Operation.
1 Line voltage is applied across terminals
L1 &L3 of the thermostat. ECO is
closed, so there is voltage at terminal L4
and to one side of the element.
2 Tank is cold therefore thermostat
is closed at terminal T2 (calling for heat).
This completes the circuit and allows
current to flow through the element.
3
When the thermostat is satisfied, it opens at
terminal T2 interrupting current flow through the
element. System is now in stand-by mode, waiting
for the next call for heat.
6

SEQUENCE OF OPERATION

Thermostat closed
at terminal T2
Thermostat opens
at terminal T2
Page 6
1
ECO
Closed
2
3