Service Manual

Page 11

Control Circuit Sequence (continued)

Certain other control components are available as “Optional“. These controls are specified when the installation

has unique requirements that must be safeguarded. When these optional components are installed the control

circuit wiring diagram accordingly will include these components. The optional equipment available from the

manufacturer includes the following:

 High Water Pressure Switch

 Low Water Pressure Switch

 Low Water Level Switch

 Alarm Horn

 Heating Element Sequencers

 Electrical Door Lock

Control Circuit Sequence of

Operation with Optional Controls

Line voltage from

power circuit

Appropriate line

voltage multi-tap

terminal

Same as explained on page 10 with the following

exceptions:

-Hi and Low Pressure Switch and Low Water Level

Switch when specified are always wired in series

ahead of the high-limit control.

-Heating Element Sequencers are wired in series

with contactor coils staging contactor activation at

intervals of approximately 20 seconds.

-Alarm Horn is wired in series ahead of the

thermostat. It monitors only the High and Low

pressure switch, Low Water Level Switch and the

High-Limit (ECO). If either of these switches open,

power to the horn relay is interrupted causing the

relay to close, sounding the alarm horn.

-Electrical Door Lock is wired in parallel to secure the

access to the water heater control cabinet. This

device will lock the control cabinet door when the

120VAC control circuit voltage is applied. Once the

door is opened, the water heater can be re-

energized, if necessary, for service diagnosis.

Control Circuit Wire Diagram

Showing OpƟonal Controls