H7
Ideal Communication Fault With External Controls

Ideal boiler shows H7 and may not respond correctly to thermostat

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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

Faulty OpenTherm or digital room thermostat, Loose control wiring, Incorrect wiring at boiler terminals, PCB communication port fault

How to Fix / Troubleshooting

Safety first: Isolate power before touching any control wiring. If unsure, do not remove the boiler front panel.

User checks:

  • Check thermostat batteries: If you have a wireless Ideal Halo or similar control, replace the batteries and ensure it is paired correctly.
  • Check programmer settings: Confirm heating and hot water schedules are set correctly and that the thermostat is calling for heat.
  • Power reset: Turn off the boiler and controls for a few minutes, then turn back on.

If H7 persists, an engineer should check control wiring, test the external control, and verify PCB communication circuits.

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Repair Difficulty

Medium 3/5

Required Part

Room Thermostat / Control Interface
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