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Hi Guys,


Here is a pick of my solar water heater.

The first 2 years it was installed incorrectly. You can see the space between the pool heaters where the solar collector was mounted.

It worked well in summer but in winter it was useless.

I built the new frame myself and changed all the pluming over. I have now also insulated the pipework and it works well to date.

I would love to perhaps add a 2nd flat collector, but not yet sure of how and where.





My latest project I am working on is not so much energy saving, but rather money saving.

My garden is irrigated with clean water, but the monthly bills is krippling.

So now I have invested in a 5000L tank, some pumps and a rather lot of PVC piping.

The wellpoint should keep the tank full. Takes about 8 hours of running to fill the tank from 1/2.

The 2nd pump is activated by the irrigation system.

So far all seems to be running well.

Just need to tidy up the cabling a bit.




Problem is the pumps is now using up all the electricity I have managed to save the last year or so.

As soon as NET metering is available, I will be running the pumps, pool pump included, from solar.

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  • 1 month later...

Ok, been spending the last 2 months on Gumtree and got another 200L solar geyser and 20 vacuum tubes for a good price.

Made a new frame to tilt the vacuum tubes at 38 Degrees while also coping with an 18 degree roof slope at the same time.

The frame was too big to get galvanised, so they coated it for me.

Put it up over the long week-end.

Frame cost me about R500 in steel alone. Coating was another R500.

Copper piping and fittings was another R500, eish.

I must say that I am extremely impressed with the working of the vacuum tubes, even in cloudy weather.


Next step now would be to re-install the original flat panel and geyser on another section of my roof and get the two connected in series.

The idea is to have the flat panel pre-heat the water fed to the vacuum tube unit.

This should ensure at least 400L of piping hot water without the need for any electricity!!!




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  • 2 weeks later...

Hi Guys,


So far I can say that the vacuum tubes is by far superior to the flat panel, granted my flat panel is 8 years old.

The flat panel geyser takes the water from around 10 degrees up to around 25 degrees.

The vacuum tube system then takes it up to around 60 degrees.

Now it is possable to take a bath in the evening and a shower the next morning :)

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Right, so basically all done on the hot water side for now.

Been working great so far without any issues.

All I can see happening now is boiling water in summer. Will have to see about covering up some of the vacuum tubes for summer and perhaps adding a tempering valve to the outlet for safety, but still thinking about that one.


Vacuum tubes in action with all pipes lagged.



Old flat panels as pre-heater with all pipes lagged.



Both heaters in view to give a better idea of the layout.


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  • 1 month later...

Ok, so far all is running ok.

I am extremely impressed with the vacuum tubes.

Only had to switch on the power to the geyser for a couple of days, like when it is raining for a couple of days.


I have to repair my flat plate collector a bit, as the riser pipes is not makeing good contact with the plate at the back.

Been thinking to use either saddels or some earth strapping to fix the pipes to the backing plate.


Not really looking forward to this as I have to remove the glass.

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All geysers is fitted with a Pressure reducing valve, but also another called a T&P valve.

Basically it is a Tempreature and Pressure valve, installed after the PRV and on the geyser itself.

This valve contains a mixture of wax, which would be pushed out if the internal temp is too high or if the pressure is too high.

Unfortunately this T&P valve can only operate once ot twice at the most before it needs replacing.


Yes, overheating in summer is something to look at. I can either remove some of the vacuum tubes, or cover them up with some shadecloth.

Will get to that one once we hit summer.

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@leaves, IMHO heatpumps is more energy effcient than a normal geyser, but it still needs electrical power to heat the water.

With solar I only need to switch the power on during long cold spells, like we currently have.

Then you also need to look at the crazy contracts they force on you with heatpumps.

If you do not sign the 5 year service contract, you loose the warrenty on the unit.

Then they charge around R600 for the first year service, but after that, they can increase the price as they see fit.

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  • 1 month later...

Ok, an update on the solar water system.


I removed the glass panels from the old flat plate system and spend some hours drilling and pop-riviting loads of saddles.

Now the pipes is making good contact with the back plate again.

After this I used some NS4 black paint to re-paint the complete unit again. The old black was getting very grey.

Putting the glass back was a bit of a mission.


The diffrence in temp afterwards was significant. Normally the water felt tepid, but now it is heating up nicely.


The vacuum tube system is getting a bit scary. On a nice sunny day the water at the tap is reaching around 75C!

Would need to start looking at a cover for it during summer.

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  • 5 months later...

Ok, just some feedback for now.

Water was really getting way to hot during the summer, so I put some 50% shadenetting over the vacuum tubes.

This helped a bit, but the water is still way to hot to use as is. At least it is not releasing water via the T&P valve.


During the last 2 weeks we had some really rainy and cloudy weather, but to date the electrical power is still switched off.

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  • 1 month later...
  • 8 months later...

RIght, so winter performance was very good, but still had to use some power during rainy days, as to be expected.

I am busy increasing my PV footprint, so need some more roof space.

This means I am going to have to relocate both geysers as to cast less shade on the roof.


Currently the units is facing North West. The plan is to get them facing true North.

This would mean shifting the stands 45 degrees. My current roof slope is 20 degrees.


Lets see how this comes out....

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Steam release valves lets steam & air escape from the system - it is a must have on any vacuum tube solar water heating system and a good-to-have on the flat plate collector systems.  They look similar to vacuum breakers, but while under pressure they release steam & air until the water level reaches the valve - basically working the opposite of vacuum breakers which lets air in when a vacuum forms.


You'll be able to get it from your local hardware / plumbing shop - a few links:




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