Nest 3rd gen - no hot water control??

28 Sep 2019
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United Kingdom
Sorry another Nest thread...

Just had my Nest 3rd gen fitted to new combi boiler, W/B Heatslave II external combi (oil).

Nest fitted & working ok for heating, but not for hot water. There was no running hot water and no option in app or on stat to turn it on?

Heating engineer has set default wiring on boiler to have hot water permanently on for now, so I now have hot water. However I'd like the option of turning water on/off in app for when I'm away for a week at a time, which I frequently am.

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You need to go into the settings and change the boiler type from "combi" to "system".
Thanks, I'll give that a go. Would that not affect how it works as I have a combi boiler, not a system boiler?
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Ok, set it up as a system boiler, just testing it all now. Hot water control has appeared in the app, however I can't turn hot water on/off? If I turn on hot tap & drain the storage tank in boiler, the boiler kicks in & reheats it, this is what I want to stop it doing when I'm away.

In the app it looks like dhw is turned off.. but it's not. Presumably this is because the boiler is wired to have dhw always on, so engineer needs to change this back?

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Ok cheers muggles, I'll get him back to rewire it (or do it myself if it's straight forward) and hopefully all will be ok.

Odd that it has to be done this way, I would've thought having the dhw on/off option would be available under a combi set up.
Ok, got it set up so that the hot water isn't 'always on' and is only on when called for by Nest... however its still always on??

In the app/stat I have hot water turned off, yet using a hot tap causes the boiler to fire up to reheat heat store.

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Assuming that is a continuous cable from the boiler to the Heat Link then the wiring is correct. The boiler will always fire up when you use a tap though, as there's a flow switch inside which tells it to do that. How long does the boiler continue to fire after you've turned the tap off again?
I ran the taps for a good few minutes to drain the heat store, the boiler fired up during this and continued to run for a minute or two after I shut off tap, I think it ran until heat store was up to temperature again (it read 63° on display).

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