Sourcing conductivity controllers from China

Duty on automatic conductivity controllers

Read from the UK Trade Tariff on 18 October 2026, heading 9032 covers automatic regulating or controlling instruments and apparatus. For an electronic conductivity controller that automatically operates a dosing pump or valve, 9032 89 00 90 is the candidate line, carrying 2% duty on goods from China. Parts classified under 9032 90 00 90 also carry 2%. The table shows product variants sharing these tariff lines.

Neither candidate line records anti-dumping or countervailing duty, or a tariff suspension. Suspensions elsewhere in the heading concern specifically described equipment, not a general conductivity-controller exemption. The UK Trade Tariff attaches an import control of fluorinated greenhouse gases to both lines. The available guidance does not establish the declaration requirement for these controllers, so the importer should confirm it with their customs broker.

Confirm the commodity code from the controller's function, supplied components and whether it arrives separately or within a machine. Do not assume a display-only conductivity meter has the same classification. See automatic pH controllers for related controls within the wider heading.

Specify the probe and dosing response

State the liquid, conductivity range, required accuracy, operating temperature and wetted materials. Agree the probe type, cell constant, temperature sensor, cable length and connector. Ask whether the quoted package includes the probe, mounting fittings and calibration solution. Define display units and temperature compensation so samples and production units use the same settings.

Specify relay or analogue outputs, the pump or valve load, switching differential, alarm behaviour and response to a disconnected probe. Agree whether dosing stops on sensor failure and how settings recover after a power interruption. Test the complete probe, controller and actuator combination rather than approving the display alone.

For mains-powered models, confirm the applicable electrical safety requirements and supporting evidence with the relevant product safety authority. Electromagnetic compatibility rules cover electrical and electronic equipment liable to generate electromagnetic disturbance, subject to exceptions. Ask for the applicable declaration and supporting reports for the supplied model through testing and certification.

Worked duty example

Illustrative example, not a quote: Illustrative batch of panel-mounted automatic conductivity controllers under 9032 89 00 90, invoiced at £3,000 free on board, with £900 of freight and insurance to the UK. The customs value is £3,900. Duty at 2% is £78. Import VAT at 20% is charged on the customs value plus duty, £3,978, so it is £795.60. Import taxes total £873.60; a VAT-registered importer can usually reclaim the VAT, so the lasting cost is the £78 of duty. The import duty and VAT guide explains each step.

Inspection checklist

Probe and reading: check the supplied probe and cell constant against the order; compare readings with a calibrated reference using suitable conductivity solutions across the agreed range.

Temperature compensation: check the temperature reading and compensation settings; repeat measurements at different liquid temperatures against the agreed specification.

Control response: check switching direction, differential, alarms and actuator operation; disconnect the probe and interrupt power to verify the agreed failure behaviour.

Arrival condition: check probe tips, seals, cables, terminals and enclosure for damage; match labels, firmware and accessories to the approved sample. Use the same checks during quality inspection.

What goes wrong

A mismatched cell constant or compensation setting can produce plausible readings while dosing incorrectly. Fouling, trapped bubbles and unsuitable wetted materials can also undermine measurement. Compare samples in the intended liquid and agree cleaning and recalibration instructions before approving production.

Reversed switching logic can keep a pump running when it should stop. A controller may display an alarm without disabling dosing, or restart with unwanted settings after a power cut. Record the required response in the purchase specification and repeat the functional checks on arrival.

Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For components and parts, see sourcing for manufacturers.