Nest thermostat , water too hot

Kurooi · 09-09-2023 01:09PM #1

Hi,

I'm not sure how to manage the temperature of the water in my storage. I have a Nest thermostat and it regulates the heating and hot water both, on separate schedules. Sometimes , probably because I wasn't using as much of the water, it gets heated up to scalding hot. I don't think Nest has any temperature readings of the tank, I think I might need a sort of auto-shut off on the cylinder to basically override NEST when the tank is full and at a cozy say 45 degrees.

Is that how it normally works? How do you put a ceiling on the water temperature, if you have a NEST wired gas boiler do you regulate it via the boiler, via nest or add that onto the cylinder?

Lenar3556 · 09-09-2023 08:48PM

https://www.boards.ie/discussion/2058312960/nest-thermostat-water-too-hot

Yes, your understanding is correct.

A cylinder stat can be installed at the cylinder which will switch off this zone once the cylinder reaches a preset temperature. It will reengage the boiler when the cylinder temperature drops again - assuming your hot water schedule on the Nest is still on.

45 degrees as a water storage temperature is problematic as it can allow growth of legionella within the cylinder and pipework, which is a health hazard. 60 degrees is recommended.

If there was one or two sinks where this water temperature was problematic you can fit a mixing valve underneath which gives pre-set (moderate) temperature hot water from the tap by mixing 60 deg water from your cylinder with cold water just before it is delivered to your tap. Not big money to achieve.

Kurooi · 11-09-2023 08:01PM

https://www.boards.ie/discussion/comment/121090611#Comment_121090611

Thank you, that's great advice I think the stat is missing from mine! 60 degrees is still miles better, I will chat to a plumber I just needed to know what my problem is :)

HeidiHeidi · 11-09-2023 08:29PM

You can use the timer to regulate it.

I have a Nest, and just have the water heating timed for half an hour or an hour every second day (I had it set for an hour every morning but the water wound up too hot). Now, I'm the only one in the house so very little is used, but you could time it for two half hours in the day if you need hot water in the evenings for example.

At the start it was turning itself on at all sorts of random times of the day and the night, and I eventually pinned it down to that Legionella thing (which would suggest that there is a thermostat in my tank, now I think about it? I didn't think there was.....) Anyway, I found that setting and turned it off. So now the water bit of the Nest just operates on the timings I have set.

Nest thermostat , water too hot

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