Geyserwise Timer on HA

@TheTerribleTriplet Just reading past this post again. The vertical part caught my eye. I know you excel at maths. Please share this on vertical benefit, Thank you

Nope, I don’t do maths. I do pictures … or real-life experiences.
Real maths is for the clever oaks here, who can then draw me pictures, which I still blow up. :wink:

So, here are MY maths … very easy.

Three variables you need to take cognizance of, with vericle geysers.

  2. How it feels when I shower.
  3. And the Geyserwise temp reading on verticle geyser.

The bottom line … open the tap, feel the water BEFORE undressing:

  1. If it is boiling hot, SWAMBO is happy.
  2. If it is lekker, I’m happy.
  3. And that can be on 18-20°C displayed on the GeyserWise temp sensor.

See, the temp sensor sits at the bottom, hot water comes from the top.

Now, the caveat, warning, if the 18-20°C is a REAL 8-20°C, has happened, to get the water my level, level SWAMBO can tolerate once, that takes about 20-30min or so, versus a horizontal geyser that can take 45-60min.

As the clever oaks explain it, deduced by my simple brain, it has to do with the amount of hot/cold water mixing. A vertical geyser has a much smaller surface where the two come into contact, than a horizontal one.

I then further deduced, ok ok, real experiences, the fact that the geyser can drop from 65-30 in a matter of minutes, is simply because the cold water enters the geyser where the temp sensor is … the bottom … and has NO bearing on the hot water at the top.

Further deduced that a 65°C a verticle geyser is hot from TOP to bottom.

But o boy, you need to get a shower fast, and got the temp/timing wrong, then you have 18-20 °C for real.

Methinks, I’m sticking with verticle geysers, as I can use 2.5 hours per day (2h afternoon and 30min at 4am) using a 2kw element, to heat enough water for 4 people to shower, one batch evenings, one batch mornings.


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i have a Tecron 200 liter horizontal geyser, the element is at the bottom and the Geyserwise probe sits just about in the middle, so assume in my case, the cold water flowing in will have a larger effect on the temperature display ???

I always used to write that into the contract. The max occupancy is 1 (even if there is space for more, a single person renting a double… I would still write that in). Then I would explain to the tenant, when signing, that I am not some monster who doesn’t want friends to stay over. If your long lost cousin from Timbuktu is visiting for the week, he is welcome. If the girlfriend occasionally stays over, that is fine. If the Girlfriend starts living here 3 out of 7 days… that is a problem. And then I tell them about my first tenant who would take what I can only assume were “sexy showers” at 4AM, using up all the hot water. Tenant laughs and agrees that that is a bit much… and then we’re on the same page.

But now I am out of the housing business… :slight_smile:

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i have a flatlet that is fed by the main geyser, with not much pv this winter in Cape Town, so following @Phil.g00 colleague’s advice, am using the Geyserwise to set the max temp to 40-45, so that there is not a LOT of hot water available at shower time, seems to be helping and the tenant seems to be taking shorter showers now, and when wife wants a HOT shower, she just overrides the Geyserwise :laughing: :laughing:


That wasn’t my advice. I would recommend a higher temperature, Legionella and all that.
I’d limit replenishing hot water, not a lower temperature.

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you right, did not think of that, but when pv is available i would let the temperature build to the maximum of 65 degrees

You just need 50 degrees at least once a week.


Although I’ve seen some research that indicates 50 degrees is borderline.

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LOL. thats if it rains everyday Louis, @Tariqe for a tenants is at least twice a day bath / shower. I lucky put a Meter on the line that feeds the cottage before renting, and now I have a change over Switch / CB that can add the geyser to that meter line or I can switch to my line and I will then be paying for heating.Plan this for your tenants,By the way, The Geyserwise system I have will heat the water to 55c easy in winter in JHB after a morning tenants bath has left it at 21c. Vassen discussed how he has it to 70C and the warm water can last longer, I dont want to ever shower at his house, we boil eggs at that temp. yes you just need 50c I think, but winter at 55c so it nice and hot.

Yes I do heat it to 70… actually sometimes 90 in summer since the tubes work really well then. There’s a mixing valve at the output of the geyser though similar to the one posted earlier…. If the geyser water is too hot, it mixes cold water before sending it to the house. So no chance of burning or boiling eggs.

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I did not know you could buy those or that they existed. What a smart invention !!! lol

I understand that they are regulation in some places. Especially when you are heating water so hot people could be burned by opening the tap.

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Did you change the elements in your geysers?

Actually, with any solar geyser install, the regulation state that you need to have a mixing valve installed to prevent scalding especially fir children or the elderly.

An evacuated tube system can easily beyond 100 degrees if not used for a few days.


LOL There is nothing like Afrikaans to describe things? Never heard this term so did the search thing
Sy wat altyd met besem opstyg … I am sure you would have meant. She who always must be obyed. , I am terified of the “Boss” at home :face_with_hand_over_mouth:

Kyk, hulle sê mos jy moet daai engel se vlerke nooit knip nie, want hulle vlieg net verder op 'n besem.