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Nicholas AcostaAug 3, 2025
What to do if my Worcester Comfort+ I RF/Stat RF shows A91 error?
- BbfrancoAug 4, 2025
If your Worcester Control Unit displays error code A91, it indicates a communication problem via EMS or that the control unit isn't connected to a heat source. First, verify the EMS connection. Also, ensure that the key is correctly installed.