--- title: Naboo - How do you solve the error message “A81 Calfree flow alarm”? description: A81 Calfree flow alarm (only for appliances with CDSS option) warns of an anomaly in CalFree consumption. This message does not necessarily require the intervention of a technician; check the presence --- [Skip to content](https://support.lainox.com/en/knowledge/naboo-how-do-you-solve-the-error-message-a81-calfree-flow-alarm#main-content) - [English](https://support.lainox.com/en/knowledge/naboo-how-do-you-solve-the-error-message-a81-calfree-flow-alarm) - [Deutsch](https://support.lainox.com/de/knowledge/naboo-wie-löst-man-das-problem-der-fehlermeldung-a81-alarm-fluss-calfree) - [Español](https://support.lainox.com/es/knowledge/naboo-cómo-resolver-un-mensaje-de-error-a81-alarma-de-flujo-calfree) - [Français](https://support.lainox.com/fr/knowledge/naboo-comment-résoudre-le-message-derreur-a81-alarme-flux-calfree) - [Italiano](https://support.lainox.com/knowledge/naboo-come-risolvere-messaggio-errore-naboo-a81-allarme-flusso-calfree) English Show submenu for translations ![LAINOX bianco 500.png\]](https://support.lainox.com/hs-fs/hubfs/LAINOX%20bianco%20500.png?height=40&name=LAINOX%20bianco%20500.png) Open main navigation Close main navigation - - [English](https://support.lainox.com/en/knowledge/naboo-how-do-you-solve-the-error-message-a81-calfree-flow-alarm) - [Deutsch](https://support.lainox.com/de/knowledge/naboo-wie-löst-man-das-problem-der-fehlermeldung-a81-alarm-fluss-calfree) - [Español](https://support.lainox.com/es/knowledge/naboo-cómo-resolver-un-mensaje-de-error-a81-alarma-de-flujo-calfree) - [Français](https://support.lainox.com/fr/knowledge/naboo-comment-résoudre-le-message-derreur-a81-alarme-flux-calfree) - [Italiano](https://support.lainox.com/knowledge/naboo-come-risolvere-messaggio-errore-naboo-a81-allarme-flusso-calfree) English Show submenu for translations - [Go to Lainox.com](https://www.lainox.com/) [Go to Lainox.com](https://www.lainox.com/) Lainox Support - There are no suggestions because the search field is empty. 1. [Home](https://support.lainox.com/en/knowledge) 2. [Naboo](https://support.lainox.com/en/knowledge/naboo) 3. [Messages](https://support.lainox.com/en/knowledge/naboo#messages) # Naboo - How do you solve the error message “A81 Calfree flow alarm”? A81 Calfree flow alarm (only for appliances with CDSS option) warns of an anomaly in CalFree consumption. **This message does not necessarily require the intervention of a technician; check the presence of product in the tank**. ### Description The CalFree flow sensor does not generate pulses when the boiler pump is activated. There is therefore no liquid in the CalFree suction circuit. **Warning: check that the CalFree tank contains the product.** ### Reset The error is automatically reset when fluid flow in the circuit is restored by activating a CalOut cycle. ### Checks Check the following: - Presence of CalFree in the tank. - Correct positioning of the cap. - Product suction circuit; any cracks or bad connections can lead to air being sucked in because it is less dense than the product. - Operation of the boiler pump. - Electrical connections between flow meter and control board. - Control board connections and its operation. - [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