Learning outcomes
- Explain the key principles of pump starters, interlocks and level control.
- Carry out a structured practical check or configuration task.
- Recognise common faults, risks and evidence needed for diagnosis.
Module 4 · Lesson 2
Pump starters, interlocks and level control
Build reliable pump control using level, pressure, flow, duty/standby rotation and dry-run protection.
Before you begin
Control narrative, P&ID, I/O list and level/pressure instruments.
Safety: Use site procedures, approved test equipment and competent supervision. Never bypass a protection or interlock without formal control.
Step-by-step learning
- List every start permissive, stop condition, alarm and trip.
- Define duty/standby selection and automatic changeover behaviour.
- Test low-level, high-level, pressure, flow and overload interlocks individually.
- Confirm the pump state shown on SCADA matches actual feedback, not merely the command.
Ian's practical tips:
- Use separate “commanded”, “running” and “available” states. They are not the same thing.
- A failed feedback timer is one of the best ways to catch a broken coupling or failed contactor.
Fault-finding questions
- What should be happening, and what evidence proves it?
- Where is the last known correct signal, voltage, state or process condition?
- What changed immediately before the fault?
- Can the system be divided into smaller testable sections?
Practical activity
Create a one-page test record for this lesson. Include expected values, measured results, equipment used, risks controlled, defects found and the final proven condition.