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Emily VasquezAug 9, 2025
What to do if my AL-KO HWA 4500 comfort shows 'ALARM CHECK PRE 1.5 BAR'?
- DDominic HooverAug 9, 2025
The 'ALARM CHECK PRE 1.5 BAR' message indicates that the AL-KO Water Pump has switched off as a protection against overheating. This is often due to a fault on the pressure side, such as a leak. Even small leaks on water taps and toilets can cause the system pressure to drop. You should check the pressure line and draw-off points for leaks. Also, check and clean the check valve in the filter chamber. After rectifying the fault, confirm with SET to restart the pump. Be aware of potential hot water when the restart occurs.