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Solar Geyser Problems (Thermosyphon system) Advice would be greatly appreciated.


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Hello Guys. 

This forum is my last resort. 
Gentlemen a while ago our town received some serious hail and we had to get insurance to come replace the Evacuated Tube and whole manifold for the tubes as it was quite aged as I understand. The guys came out and replaced the manifold and tubes, but since the replacement the system doesn't get as hot as what it did in my personal opinion, I have had to put my solar geyser on every night since winter started as we have had some nice days. When I climb on the roof to check the system the inlet to the manifold is cooking hot but the outlet is luke warm (See attached pictures). Please if anyone can assist in answering the following. 

1) Is it possible that the manifold is not working properly ? 

2) Why is the outlet pipe back into the geyser not getting as hot as the inlet pipe ? 

3) Should I get the insurance or plumber to replace the manifold ? 

4) Is it possible that the Thermosyphon system is not working properly ? 

The temperatures in winter are lower I understand that completely, but I have a true north facing geyser and it does get quite hot up there. I cannot hold my hand on the inlet pipe for long else I will burn. Is the system not working properly ? Please see attached pictures. 

As of this post right now it has been 21'C today. Pure Sun. 

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Edited by Great Whit3
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  • Great Whit3 changed the title to Solar Geyser Problems (Thermosyphon system) Advice would be greatly appreciated.
3 hours ago, Great Whit3 said:

Hello Guys. 

This forum is my last resort. 
Gentlemen a while ago our town received some serious hail and we had to get insurance to come replace the Evacuated Tube and whole manifold for the tubes as it was quite aged as I understand. The guys came out and replaced the manifold and tubes, but since the replacement the system doesn't get as hot as what it did in my personal opinion, I have had to put my solar geyser on every night since winter started as we have had some nice days. When I climb on the roof to check the system the inlet to the manifold is cooking hot but the outlet is luke warm (See attached pictures). Please if anyone can assist in answering the following. 

1) Is it possible that the manifold is not working properly ? 

2) Why is the outlet pipe back into the geyser not getting as hot as the inlet pipe ? 

3) Should I get the insurance or plumber to replace the manifold ? 

4) Is it possible that the Thermosyphon system is not working properly ? 

The temperatures in winter are lower I understand that completely, but I have a true north facing geyser and it does get quite hot up there. I cannot hold my hand on the inlet pipe for long else I will burn. Is the system not working properly ? Please see attached pictures. 

As of this post right now it has been 21'C today. Pure Sun. 

1.jpg

2.jpg

3.jpg

4.jpg

5.jpg

6.jpg

7.jpg

Are you sure that the legends in the pictures are correct?

Just wondering if the hot pipe is not the output from manifold to geyser and the cold pipe the inlet to the manifold. 

Just grasping at straws  as I don't know solar geysers. 

Edited by Scorp007
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Whichever side is hot, that is the output of the manifold, and the direction the water will be flowing towards. Possibly the installers never put enough thermal paste on the copper rods that push into the manifold, therefore not enough heat is transferred, compared to your old installation.

9 hours ago, Great Whit3 said:

4) Is it possible that the Thermosyphon system is not working properly ?

If the direction of flow has changed, possibly yes.

Has the length and height of the pipes changed with this new refit?

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Just based on the pictures I would think that the pipe from the manifold that is hot should be connected to the hot water from the geyser. That means the vertical pipe with the lagging insulation. 

The pipe tagged outlet to geyser at the bottom of the geyser to manifold that is cold seems to be correct. 

My reasoning is the hot water from manifold is now directly next to the cold water inlet. 

Currently both pipes to/from the manifold are connected to the bottom of geyser being the cold part of the geyser. 

Again coming from a lay person when talking solar geysers. 

 

Edited by Scorp007
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14 hours ago, TimCam said:

Whichever side is hot, that is the output of the manifold, and the direction the water will be flowing towards. Possibly the installers never put enough thermal paste on the copper rods that push into the manifold, therefore not enough heat is transferred, compared to your old installation.

If the direction of flow has changed, possibly yes.

Has the length and height of the pipes changed with this new refit?

Is it possible that the manifold is the wrong way around as hot rises. 

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14 hours ago, TimCam said:

Whichever side is hot, that is the output of the manifold, and the direction the water will be flowing towards. Possibly the installers never put enough thermal paste on the copper rods that push into the manifold, therefore not enough heat is transferred, compared to your old installation.

If the direction of flow has changed, possibly yes.

Has the length and height of the pipes changed with this new refit?

I don't think they used any thermal paste as I was present on site of the day they installed? Is this an important effect to do ? 

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Firstly...I am NOT a plumber.

A few months back I was called by a neighbor to look at his setup which mirrored the OP issue. Hot water too cold.

On inspection I found that there is a THERMOSTATIC mixer valve which blends the hot and cold to a set output temperature and has to be installed (by statute?) on all new installations. Since his water supply is low pressure, I advised him to replace the high pressure thermostaic valve, that was installed by the plumber, with a low pressure one. Since I have had no feedback from my neighbor I  assume that fixed his problem.

Maybe see if you have a thermostatic valve in your system and if it is the correct one re water pressure and if it is correct whther it can be adjusted to increase the output temperature, which I am led to believe is possible on most of these devices.

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Guys I came across my brother in law's geyser. The cold pipe runs under the tubes to the outlet of how mine is plumbed. The hot pipe on mine is the outlet of his going back into his geyser. I will contact the plumber this week. What's your guys thoughts? 

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2 hours ago, Great Whit3 said:

I don't think they used any thermal paste as I was present on site of the day they installed? Is this an important effect to do ?

Should have used thermal paste, just like you do on a PC CPU and GPU between hot IC's and Heat syncs.

Good to see your brother in laws, setup. Hope your plumber corrects yours accordingly. 👍

My 20 tube setup uses a re-circulation pump, as the geyser is below the roof.

Edited by TimCam
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  • 2 months later...

Hi, I have a problem with the solar geyzer. Since last month it's been mixing cold & hot water, all the taps are having hot water only & the worst is when touching taps you become choked.so I reported the problem at the municipality since there was earthleakage.They came & fixed the electricity box.they said that its okay.last week there was a rupture of a pipe, I called the plumber.The plumber fixed the pipe but said the water is choking , meaning that there is electricity in the water.now I don't know what could be the problem. The plumber told me about the mixer for solar geyzer but couldn't find it at hardwares because they say solar geyzers doesn't have thermostat.should I change the geyzer?

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