Display shows E07 and the chemical injection or metering system will not operate.

Safety: Wear gloves and eye protection when handling chemicals. Disconnect power before servicing internal components.

• Check chemical supply: Ensure the chemical jug is not empty and that the pickup tube is fully submerged. Inspect the pickup tube for cracks or loose fittings that could draw air.
• Clean metering valve: Locate the chemical metering valve or orifice on the Prochem unit. Remove and soak in warm water to dissolve chemical buildup. Use a soft brush to clear any deposits. Reinstall and test.
• Prime the chemical line: If the system has a prime function, run it until a steady stream of chemical is visible at the wand or test outlet. Air in the line can trigger dosing faults.
• Test chemical pump: Access the chemical pump and check for voltage at the pump terminals when dosing is commanded. If voltage is present but the pump does not run, replace the Prochem chemical pump.
• Control PCB driver: If the pump is good but never receives voltage, the chemical pump driver circuit on the control PCB may have failed. Replace the control PCB.