Hot Water Tank heating up for no reason

[KeithL36]

Hi. Hoping someone can help me. I have a hot water tank which the NEST thermostat heats as it should either on schedule or boost. But every now and again the system heats the water up in the tank for no reason. The apt shows no indicator as to why it's initiated this, as far as it's concerned the hot water system is off. On settings turned Hot Water off and Home/Away Assist off but makes no difference. Seems to mostly happen at night which indicates it's the temp of the hot water tank driving it but can't find anything that would substantiate this.  The heating system has a safety temp option but not the hot water?  

[AlexD]

Thanks for reaching out to us here @KeithL36 . Sorry for the later reply. I would be happy to try and assist.

It's possible that this is the Bacteria prevention feature. You can read more about it and how to change the settings here: https://goo.gle/2WTVgRK but in short, it activates the system from time to time to reduce the chance of Legionella bacteria growing in the water. You can turn this feature off, just to test, and see if this changes the behavior of your system. If it does, you can then decide if you want to keep it on or off. 

[george_t]

Hi @KeithL36. Just checking in, did you manage to read the last message from my colleague?

[KeithL36]

Hi, yes I did read it. I turned off that feature and so far there has been no recurrence that I have been aware of so I think that Alex may have been right on the button. Been waiting to check as hard to know that something intermittent has stopped occurring. I find it strange that the app. does not duplicate the thermostat more closely, never considered that the thermostat itself would have more settings. Many thanks Alex for your help.

[DragosC]

Thank you. We'll make sure to pass your thanks over to our colleague. Should anything else come up, we're just a message away. Have a great day ahead and stay safe!