Red Lion TCU - Manual (Page 19)

Heater Current Monitor Wiring
Units with Heater Current Monitor option have two input terminals to
receive the output directly from a 100 mA current transformer.
Caution: Never connect a current transformer with a rating other than 100 mA.
These terminals are labeled “Second Input CT”, see Figure 10, Heater
Current Wiring. Terminal placement varies with model. See controller label
for actual terminals. There is no polarity observation for these inputs.
Program Disable Or User Input Wiring
Some models have Terminal #7 as the User Input, which is programmable
for a variety of functions. Other models have Terminal #7 dedicated to the
program disable function. Any form of mechanical switch may be connected
to terminal #7. Sinking open collector logic with less than 0.7 V saturation
may also be used (no pull-up resistance is necessary).
Note: Do not tie the commons of multiple units to a single switch. Use either a
multiple pole switch for ganged operation or a single switch for each unit.
AC Power Wiring
Primary AC power is connected to the separate two position terminal block
labeled AC. To reduce the chance of noise spikes entering the AC line and
affecting the controller, an AC feed separate from that of the load should be
used to power the controller. Be certain that the AC power to the controller is
relatively “clean” and within the -15%, +10% variation limit. Connecting
power from heavily loaded circuits or circuits that also power loads that cycle
on and off , (contacts, relays, motors, etc.) should be avoided.
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Figure 10, Heater Current Wiring