Stella Z temp reporting

[willboyes]

I've got our heating system running well with about 8 Stella Z valves, controlled by a Razberry module using Domoticz. The timers on the valves work fine, but they are poor at reporting back the current temperature to Domoticz. They seem to work fine when the system is rebooted, but then stop sending temperature values shortly afterwards. They are all set to 1800 seconds polling.

Does anyone have any suggestions for why this might be happening? We're going away in a few weeks so it'd be nice to be able to check on the temperature while we're away!