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Electric Heater Option
The electric coils on the heater are controlled using Silicon Controller Rectifier
(SCR) controls. SCR is a
time proportioning type controller that modulates the heater and supplies the exact amount of power to
match the heat demand.
The three black wires from the electric heater will need to be field wired to the disconnect switch.
Figure 25 - Electric Heater Option
1.
Terminal Strip
– Central location to terminate control wiring. Should be used for troubleshooting.
2.
Stage Controller
– Controls multiple heating stages in a pre-determined sequence. Works in
conjunction with a proportional thermostat (not shown). A sensor is mounted in the blower housing for
discharge control. The set-point is mounted remotely for either space control or discharge control.
3.
Stage Fuses
- Protect the total load and/or individual heater stages.
4.
Mercury Contactor
– Provides power to the individual stages of the heater (optional for quieter
operation).
5.
Coil Contactor
- Energizes coil when there is a signal from step controller.
6.
Magnetic Contactor
- Provides power to the individual stages of the heater.
7.
Transformer
- Supplies power to the control circuit. Supplied with a fuse.
8.
Solid State Relay (SSR)
- Proportionally controls the amount of power transmitted to the heating
elements.
9.
Disconnect Switch
– Interrupts power to the electric coil.
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