How to Troubleshoot a Plasma Cutter That Won't Start

Linda Cheshire

Plasma cutters, or torches, are used to cut steel, metals and other materials of varying thickness. The technology developed in the 1960s and became widespread by the 1980s. An inert gas, or compressed air, is blown through a nozzle while an electrical arc is produced. The electrical arc transforms some of the gas into plasma which contacts the material to be cut. Proper maintenance and inspection can minimize plasma cutter failures.

A damaged or faulty component can prevent a plasma cutter from starting.
  1. Inspect the plasma cutter's electrode if the tool fails to start, or operates only intermittently. If the electrode has a wide pit and the copper is black or blue, this may be due to a low flow of coolant. Verify the flow rate of the tool. If the flow rate is not operating at model specification, check for line kinks or leaks that may impede coolant flow. Replace kinked or leaky lines, and replace completely melted electrodes.

  2. Check the electrode for gas contamination. If the electrode has a heavy layer of black residue, gas contamination could be preventing the torch from starting or operating efficiently. Place a clean paper towel beneath the torch while gas is flowing through the tool. Any moisture or debris could be a sign of gas contamination.

  3. Inspect the interior of the nozzle for damage. A slot, gouge or "keyhole" within the nozzle may indicate low pressure within the plasma chamber. Check for gas line links by applying soapy water to all fittings and lines, then pressurize the lines.