Actuator Response - heat-timer DIGI-SPAN Elite MC Series Installation And Operation Manual

Actuator response

MCA Elite Does not Move the 4-20mA Actuator
Check the Set Point (page 13) and Differential (page 16) settings. If the System Sensor reading is within the Differential
band, the MCA Elite may not adjust the modulation position. Otherwise, check the external DC power supply for a
voltage between 30 to 36VDC. Then, measure the current. It should measure between 4 and 20mA. If it does not, the
MCA Elite may be damaged.
MCA Elite Does not Move the voltage Actuator
First, check that the modulation signal of the actuator match the Modulation signal setting in the Startup menu. See
"Modulation Signal" on page 11. Check the Set Point (page 13) and Differential (page 16) settings. If the System Sensor
reading is within the Differential band, the MCA Elite may not adjust the motor position. If this is not the case, use a
DC volt meter to measure voltage from the Blue and Red MCA Elite output wires. The meter should register a voltage
within the voltage range selected from the Modulation Signal in the Startup menu. If it does not, MCA Elite may be
damaged.
MCP Elite Does Not Move the 135Ω Actuator
Check the Set Point (page 13) and Differential (page 16) settings. If the System Sensor reading is within the Differential
band, the MCP Elite may not adjust the modulation position. If this is not the case, the MCP Elite output can be tested
with an ohm meter. Disconnect the MCP Elite modulation output wires (Red, White, and Blue). If the System value has
been below the Set Point, then an ohm reading between the Red to Blue wires should be less than 25Ω and the reading
from Red to White should be more than 110Ω. If the system value has been above the set point, then an ohm reading
from the Red to Blue wires should be more than 110Ω and the reading from Red to White should be less than 25Ω. If
the above tests fail, then the MCP Elite is damaged.
MCF Elite Does not Move the Floating Actuator
First check the valve wiring. The MCF Elite does not source power to the actuator. Instead, a separate source of
power must be wired to the actuator. See "Wiring the Floating Output" on page 9. Next, remove any wires connected to
the Red, White, and Blue output wires. Switch the control Valve Mode to Close. There should be no continuity across
the White and Red wires. If continuity exist, the MCF Elite may be damaged. There should be continuity across the
Red and Blue wires. If continuity does not exist, the MCF Elite may be damaged.
MC Elite Does not control the system to hold the set point
If the system temperature/pressure is overshooting or undershooting the Set Point by a small amount, increase the
Differential (page 16) value. If the system temperature/pressure significantly overshoots and undershoots the Set Point,
decrease the Gain (page 16) setting by one or two points. If the system temperature/pressure is almost always below
the Set Point, increase the Gain setting by one or two points. Wait approximately 15 minutes after each change before
evaluating the system.
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MC-Elite Installation and Operation Manual