--- title: Sapiens - How to resolve error message “A04 Water shortage alarm“? description: A04 Water shortage alarm warn that water is not detected. As consequence units open water solenoid and show the message after a short delay. 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[Home](https://support.lainox.com/en/knowledge) 2. [Sapiens](https://support.lainox.com/en/knowledge/sapiens) 3. [Messages](https://support.lainox.com/en/knowledge/sapiens#messages) # Sapiens - How to resolve error message “A04 Water shortage alarm“? A04 Water shortage alarm warn that water is not detected. As consequence units open water solenoid and show the message after a short delay. **This message does not necessarily require the intervention of a technician; the causes of the failure can be external.** ### Description Pressure switch PA for direct injection units; level probes for boiler units do not detect water presence. ### Warning On boiler units water must be conductive >50µS  On direct injection units water pressure must be >50Kpa ### Reset Message reset automatically. In case of PA defect is possible to deactivate it from: Service Level / oven model / pressupre switch: OFF ### Checks Perform following checks: - Check opening of water tap with the hand shower if present - Check if water pressure is adequate. - Check solenoid valve S1 (out 35) or S2 (out 53). - Check pressure switch PA. - Check if water is conductive. - Check boiler level probes. - Check if drain valve close. - [Naboo](https://support.lainox.com/en/knowledge/naboo#main-content) - [Installation](https://support.lainox.com/en/knowledge/naboo#installation) - [Use](https://support.lainox.com/en/knowledge/naboo#use) - [Messages](https://support.lainox.com/en/knowledge/naboo#messages) - [How to](https://support.lainox.com/en/knowledge/naboo#how-to) - [How it works](https://support.lainox.com/en/knowledge/naboo#how-it-works) - [Sapiens](https://support.lainox.com/en/knowledge/sapiens#main-content) - [Installation](https://support.lainox.com/en/knowledge/sapiens#installation) - [Use](https://support.lainox.com/en/knowledge/sapiens#use) - [Messages](https://support.lainox.com/en/knowledge/sapiens#messages) - [How to](https://support.lainox.com/en/knowledge/sapiens#how-to) - [How it works](https://support.lainox.com/en/knowledge/sapiens#how-it-works) - [Neo24hours](https://support.lainox.com/en/knowledge/neo24hours#main-content) - [Installation](https://support.lainox.com/en/knowledge/neo24hours#installation) - [Use](https://support.lainox.com/en/knowledge/neo24hours#use) - [Messages](https://support.lainox.com/en/knowledge/neo24hours#messages) - [How to](https://support.lainox.com/en/knowledge/neo24hours#how-to) - [How it works](https://support.lainox.com/en/knowledge/neo24hours#how-it-works) - [Oracle](https://support.lainox.com/en/knowledge/oracle#main-content) - [Installation](https://support.lainox.com/en/knowledge/oracle#installation) - [Use](https://support.lainox.com/en/knowledge/oracle#use) - [Messages](https://support.lainox.com/en/knowledge/oracle#messages) - [How to](https://support.lainox.com/en/knowledge/oracle#how-to) - [How it works](https://support.lainox.com/en/knowledge/oracle#how-it-works) - [Puff](https://support.lainox.com/en/knowledge/puff#main-content) - [Installation](https://support.lainox.com/en/knowledge/puff#installation) - [Use](https://support.lainox.com/en/knowledge/puff#use) - [Messages](https://support.lainox.com/en/knowledge/puff#messages) - [How to](https://support.lainox.com/en/knowledge/puff#how-to) - [How it works](https://support.lainox.com/en/knowledge/puff#how-it-works) - [Zoom](https://support.lainox.com/en/knowledge/zoom#main-content) - [Installation](https://support.lainox.com/en/knowledge/zoom#installation) - [Use](https://support.lainox.com/en/knowledge/zoom#use) - [Messages](https://support.lainox.com/en/knowledge/zoom#messages) - [How to](https://support.lainox.com/en/knowledge/zoom#how-to) - [How it works](https://support.lainox.com/en/knowledge/zoom#how-it-works) [![Chill listening crop-3](https://support.lainox.com/hs-fs/hubfs/LAINOX-1.png?width=88&height=24&name=LAINOX-1.png "Chill listening crop-3")](https://lainox.com/) Copyright © 2026, LAINOX Ali Group S.r.l. a Socio Unico