Remeha
Calenta 28s
System Boiler
28kW
2018-present
ErP A
35 fault codes
<p>The Calenta 28s is a system boiler from Remeha, available at 28kW output. Produced 2018-present.</p>
Calenta 28s Fault Codes 35
Code
Description
Severity
Type
01
No Flame Detected
The boiler has failed to ignite or lost its flame. Gas supply, ignition electrode, or gas…
High
Engineer
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02
Safety Thermostat Activated
The boiler has exceeded its maximum safe temperature and the safety thermostat has triggered.
High
Engineer
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03
Flue Gas Thermostat Activated
The flue gas temperature has exceeded the safe limit.
High
Engineer
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04
False Flame Signal
The ionisation electrode is detecting a flame when the gas valve should be closed. This is…
High
Engineer
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05
Flame Lost During Operation
The flame was established but has been lost during normal operation.
High
Engineer
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06
Fan Fault
The fan is not running at the correct speed or is not starting.
High
Engineer
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07
Air Pressure Switch Fault
The air pressure switch is not detecting correct airflow.
High
Engineer
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08
Gas Valve Fault
The gas valve is not responding correctly to commands from the PCB.
High
Engineer
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10
Flow Temperature Sensor Fault
The flow NTC temperature sensor has developed a fault.
Medium
Engineer
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11
Return Temperature Sensor Fault
The return NTC temperature sensor has a fault or open circuit.
Medium
Engineer
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12
DHW Temperature Sensor Fault
The domestic hot water NTC sensor has developed a fault.
Medium
Engineer
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16
Pump Over-Speed
The pump is running faster than expected, possibly indicating an internal fault.
Medium
Engineer
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18
PCB Fault
The printed circuit board has an internal communication or memory error.
High
Engineer
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20
Outdoor Sensor Fault
The outdoor temperature sensor is faulty or disconnected.
Low
Engineer
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23
Flow/Return Differential Too Large
Temperature gap abnormal — poor circulation.
Medium
Engineer
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27
Ignition Electrode Fault
The ignition electrode is worn or not sparking correctly.
High
Engineer
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30
Three-Way Valve Fault
The diverter/three-way valve is stuck or not switching correctly between heating and hot water.
Medium
Engineer
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35
Combustion Fault
The combustion quality is outside the acceptable range.
High
Engineer
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