# Help creating a simple flow ? anti-legionella program

**URL:** <https://community.homey.app/t/help-creating-a-simple-flow-anti-legionella-program/19214>\
**Category:** Flows\
**Tags:** z-wave\
**Created:** [October 13, 2019, 10:30am UTC](https://community.homey.app/t/help-creating-a-simple-flow-anti-legionella-program/19214 "2019-10-13T10:30:04Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Kjetil\_Knutsen](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/kjetil_knutsen/32/8202_2.png) [@Kjetil\_Knutsen](https://community.homey.app/u/Kjetil_Knutsen)\
**Post date:** [October 13, 2019, 10:30am UTC](https://community.homey.app/t/help-creating-a-simple-flow-anti-legionella-program/19214/1 "2019-10-13T10:30:04Z")

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sorry for posting av novice question.

Need a flow that controls my water heater the first of every month it should heat it to 75 C.

someting like this:

 ![flow%20vvb](https://us1.discourse-cdn.com/flex025/uploads/athom/original/3X/1/f/1fe9a53694cdce8de5f2d2e7dc1d859c02b5cf11.png)

will this work ?

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**Author:** ![robertklep](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/robertklep/32/160628_2.png) [@robertklep](https://community.homey.app/u/robertklep)\
**Post date:** [October 13, 2019, 11:46am UTC](https://community.homey.app/t/help-creating-a-simple-flow-anti-legionella-program/19214/2 "2019-10-13T11:46:49Z")

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That will turn on the heater for the entire week, which I don’t think is your intention.

If you know how long it will take to heat the heater up to 75°C (say 2 hours), you can turn it on and under “Then” add a card to turn it off with a delay of 2 hours. Otherwise, you need to periodically check if the temperature has reached 75°C and turn it off when it has.

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**Author:** ![Kjetil\_Knutsen](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/kjetil_knutsen/32/8202_2.png) [@Kjetil\_Knutsen](https://community.homey.app/u/Kjetil_Knutsen)\
**Post date:** [October 13, 2019, 2:28pm UTC](https://community.homey.app/t/help-creating-a-simple-flow-anti-legionella-program/19214/3 "2019-10-13T14:28:32Z")

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ok thx…

back to the drawing board…

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**Author:** ![Osorkon](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/osorkon/32/43026_2.png) [@Osorkon](https://community.homey.app/u/Osorkon)\
**Post date:** [October 13, 2019, 2:59pm UTC](https://community.homey.app/t/help-creating-a-simple-flow-anti-legionella-program/19214/4 "2019-10-13T14:59:12Z")

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> [@robertklep](#):
>
> “Then” add a card to turn it off with a delay of 2 hours.

But note! After homey reboot (ptp, update, flow, unplanned, etc.) the delay doesn’t work anymore!

I would recommend to work with the Countdown App because the countdown is still alive after a reboot.

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**Author:** ![Emil\_Lichtenberg](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/emil_lichtenberg/32/12333_2.png) [@Emil\_Lichtenberg](https://community.homey.app/u/Emil_Lichtenberg)\
**Post date:** [October 14, 2019, 8:01pm UTC](https://community.homey.app/t/help-creating-a-simple-flow-anti-legionella-program/19214/5 "2019-10-14T20:01:04Z")

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What sensor do you use (qubino?)

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**Author:** ![Kjetil\_Knutsen](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/kjetil_knutsen/32/8202_2.png) [@Kjetil\_Knutsen](https://community.homey.app/u/Kjetil_Knutsen)\
**Post date:** [October 15, 2019, 6:45am UTC](https://community.homey.app/t/help-creating-a-simple-flow-anti-legionella-program/19214/6 "2019-10-15T06:45:13Z")

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I use HeatIT z-relay