Hot water history issues

[Jojochakkara]

Hi,

See 2 issues with Hot water heating

1. Unable to see when heating history. There is a post but I am unable to make out what steps meeded to see Hot water history. I can see the Radiator history though.

2. The boiler is fired but it does not show on App but does on device

Thanks

[blackfs]

I have a similar issue.  Boiler fires up, but I don’t understand why.  No heating is required because temp in room is higher than that set on the Nest thermostat, and I don’t have any schedule set for heating the hot water, but the boiler seems to be starting up to heat the hot water tank, and I don’t really understand why.  I there anywhere that I can check to see what is actually calling for the boiler to fire up?

[Jojochakkara]

That is due to Bacterial prevention mode.

[AlexD]

Hi @blackfs . I would be happy to try and assist you with your thermostat. 

Like @Jojochakkara mentioned, thank you for the suggestion, it could be the bacteria prevention. You can read more about this feature here. In short, if your hot water is not on for at least 2 consecutive hours within 48 hours the hot water will turn on to heat it and reduce the risk of Legionella bacteria.

You will see a water drop icon on the bottom of the thermostat display in a circle when this occurs. Let me know if you noticed that symbol or if you notice it next time it occurs. 

[blackfs]

Thanks - I’ve checked to see, and indeed, the bacteria prevention mode was switched on.  I’ve had this problem since the Nest was installed, but never could understand why it was happening.  ~Most times in the past it was during cold weather, and for some reason, the heating upstairs, which is linked to the hot water heating loop would come on.  I suspected that it was some kind of frost prevention, but more recently while it happened in hot weather while the heating  was not being called for, it seemed really strange.  I didn’t even know about the bacteria prevention mode, and since our hot water is heated from an immersion heater connected to solar panels in the summertime, then most of the time, bacteria prevention would not be needed.  I’ve now switched this mode off so should be able to same some valuable heating oil given the very drastic increase in price over the past few months.  Thanks for all your help.

[DragosC]

Thanks for letting us know, @blackfs . That's great news. I'll have to close this thread. Should anything else come up, please open another thread and we'll take it from there. Have a good one and stay safe!

[AlexD · Accepted solution]

Hi @Jojochakkara . I would be happy to try and assist you.

For your first question, regarding the hot water history, the hot water history is not something that can be viewed. You can only check the heating history. This is due to the fact that most hot water tanks have a separate thermostat on them, where you set the hot water temperature. So even though you may have the hot water tank set to heat 24/7 on the Nest app, it will be off during this period multiple times, as the thermostat on the tank will turn it off when the temperature is achieved, and it takes a long time usually for that temperature to drop. So your schedule may be 24/7, for example, but the water tank will be on for a shorter period of time as it is controlled by that separate thermostat. 

As for the boiler turning on outside any schedule, we can check to see what may be going on together. For starters, how long has the device been installed for before you first noticed this behavior occurring?