When I create a new item:
key: grpsum["WWW","vfs.fs.size[/home,free]","last","0"]
type item: zabbix agreggate
type information: float

I get a error: Type of received value [6323388723200.000000] Is Not Suitable for value
type [Numeric (float)]

I have group - name WWW, in this group I have 25 host with items: vfs.fs.size[/home,free]. Items have type zabbix agent, type information float

I have other item - zabbix agregate for monitoring traffic in interface : grpsum["WWW","net.if.in[eth0,bytes]","last","0"] but its OK. For this item I also have float.