Radson: Digital RF thermostat messages
Err, Lo and Hi on the Radson Digital RF 51042: sensor faults and floor limits. These are not boiler fault codes.
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Selection for the Radson Digital RF thermostat, manual 51042(2). Err in position 6 reports an internal or external sensor fault according to the flashing symbol; Lo and Hi in position 4 indicate lower and upper floor limits. The manual also distinguishes the limiter sensor in position 4 (Er in EN/NL, Err in FR). Identify the position and symbol before interpreting the message. Ordinary hydronic radiators do not display these messages, and this list does not cover older Radson boilers.
3 error codes found
The questions we get asked most
Where can I find my exact boiler model?
Check the identification label accessible without dismantling, the invoice or maintenance report. Keep the range name and all suffixes: VCW 286 or TOP 22/28 alone may not be enough.
Does Bulex F22 always mean low pressure?
No. The ThemaCondens manual cited in our article associates F.22 with insufficient water or pressure. The older ThermoMaster F24E, FAS28E and F28E manual gives excessive pressure for F22. Check the model before topping up.
Why record the subcode with Bosch EA?
The subcode can distinguish different conditions. The official Bosch lookup cited in our article gives different descriptions for EA-227 and EA-511. Check applicability to your model; do not automatically apply those results to an older Junkers.
Does my Radson radiator show a boiler code?
An ordinary radiator does not have a boiler diagnostic display. Identify the boiler or electronic controller actually showing the message, then look up its brand and model.