E10
Heatmiser Wiring Centre Communication Error

Thermostat shows E10 and cannot control heating zones via wiring centre

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Open circuit on data bus between thermostat and Heatmiser wiring centre, Reversed polarity on data lines, Too many devices on bus without proper termination, Faulty wiring centre PCB

How to Fix / Troubleshooting

Safety first: Turn off power to the wiring centre and thermostats before working on the bus wiring.

Steps:

  • Identify the data bus terminals (e.g., A/B or +/–) on both the thermostat and the Heatmiser wiring centre (UH1, UH8, etc.).
  • Check that the bus cable is connected to the correct terminals with correct polarity at both ends.
  • Inspect the cable for damage, kinks, or joints that may have failed.
  • If multiple thermostats are daisy-chained, ensure the total bus length and number of devices are within Heatmiser specifications and that termination (if required) is correctly applied.
  • Test continuity of the bus cable with a multimeter; repair or replace any open or shorted sections.
  • If wiring is correct and E10 persists on all thermostats, the wiring centre PCB may be defective and require replacement.
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Repair Difficulty

Hard 4/5

Required Part

Heatmiser Wiring Centre (e.g., UH1, UH8)
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