Common Faults with Gledhill StainlessLite

Fault Finding and Troubleshooting Guide for Gledhill StainlessLite System

Please note that all maintenance and repair tasks must be conducted by a qualified engineer. For detailed instructions, refer to the Gledhill StainlessLite manual.

Download Here : Gledhill StainlessLite Manual

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Scale Build-up:

  • In hard water areas, it's recommended to fit an in-line scale inhibitor.
  • Lowering the temperature of stored water reduces scale formation.
  • If the recovery rate is significantly affected, it may indicate scaling. In such cases, follow procedures recommended by a reputable Water Treatment Company.


  • No water at the tap: Check if the mains water supply is ON. Ensure the line strainer isn't blocked and that the combination valve allows water to flow in the correct direction.
  • Cold water at the tap: Verify if the boiler is switched ON and functioning properly. Check for airlocks in the primary system. Isolate the unit at the mains electric supply and check: i. The cylinder thermostat ii. The thermal cut-out (reset by pushing the red button) iii. The motorised valve iv. The boiler thermostat v. The boiler thermostat cut-out (if fitted)
  • Never bypass any energy cut-outs under any circumstances.
  • If units aren't heating and the heat source is electrical, ensure immersion heaters are isolated from the mains before resetting the energy cut-out. If immersion heaters need replacing, contact us for supply.

Discharge from Relief Valves:

  • If cold water discharges from the expansion relief valve, check the pressure on the expansion vessel when cold and recharge if necessary.
  • If the fault persists, and easing control doesn't help, check the Pressure Reducing Valve or the Relief Valve. Replace faulty components with Gledhill approved replacements.


  • Follow the commissioning procedure for drain down.
  • In case of an overheat fault with very hot water discharge, turn off the heat source but not the water supply.
  • After the supply cools down, check thermostats and energy cut-outs in the boiler and immersion heaters. Replace faulty components with units supplied by Gledhill and ensure they work correctly before returning the system to full operation.

It is imperative to promptly address these common problems to ensure the efficient and safe operation of the Gledhill StainlessLite system. Qualified engineers should diagnose and repair any issues in adherence to the manufacturer's guidelines and recommendations.