Heatline Capriz 25S 28S Fault codes & diagnostics

2 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

System Natural Gas 25-28 kW 2008-2016 Discontinued

Replaced by: Capriz 2

Download the Heatline Capriz 25S 28S manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

This boiler uses LED flash patterns

Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →

Fault codes

All 2 documented codes

Tap any card for details

LED / flash-pattern codes

Parts commonly replaced

Central Heating (CH) NTC sensor
Wiring harness

Digital codes

Parts commonly replaced

DHW NTC thermistor

Status & diagnostic codes

7 operating states & engineer diagnostics

Not faults — these are normal operating states. Tap to expand.

30 Status Your boiler has detected an issue with the sensors that measure how hot the water inside the system is getting. 40 Status Your boiler is struggling to accurately detect or manage the temperature of the water flowing through it, causing it to shut down to prevent overheating. 50 Status Your boiler is struggling to accurately detect or manage the temperature of the water circulating inside it, which has caused it to stop operating for safety reasons. 60 Status Your boiler is detecting an issue with the water temperature readings, which has caused it to shut down for safety. 70 Status Your boiler has detected that the water inside the system is becoming too hot, likely due to a flow issue or a faulty sensor, so it has shut down to prevent damage. 80 Status Your boiler has detected that the water temperature has risen too high or is not being read correctly, causing it to shut down for safety. 90 Status Your boiler has detected that the water temperature has risen too high or the sensor is reading incorrectly, causing the system to shut down to prevent damage.