Boiler User Manual

4
WIRING (cont’d.)
Figure 8 – Typical Wiring Diagram
Power Circuit
Terminal Block
To Other
Heater
Groups
To
Other
Heater
Groups
Typical 3 Phase Heater Group
To
Power
Curcuit
Relay
Step
Sequencer
Figure 9 – Power Circuit Detail
Low Water
Probe
120 Volt
Control Voltage
Hi Limit
Control
Electronic Resistance
Sensing Amplifier for
Auxiliary Low Water Cutoff
Figure 10 – Auxiliary Low Water Cutoff