Have the service and maintenanace on the app which can also be edited by the installer/servie engineer.
User will be sent push notifications when the unit requires service/maintenanace and will display the contact details of the installermaintenance engineer to contact or location to purchase filters such as the web shop.
Maintenance log is completed by service engineer and we have access to this in the future to ensure filters have been replaced etc and what has been modified, changed, serviced.