Which evac tubes do all like best, Tim

tim smith

Just wondering what tubes all the Solar guy's prefer. Least failures etc. Thanks in advance, Tim

Paul Pollets

V or T

Viessmann or Thermomax. Thermomax used to make the tubes for Viessmann, but no more. I find that 2% are defective out of the box. The dealer instantly replaces. I have some systems that are 12 years old...no problem.

I'm not a fan of the Chinese counterpart. High failure rate. But of course, they're less expensive.

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Bob Gagnon plumbing and heating

Thermomax Tubes

I have 4 bad ones out of 120. The latest one broke, and fell out of the array, at the neck near the heat transfer bulb, I'm still waiting for replacements. My next job will be plat panels.

Thanks, Bob Gagnon

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EricAune

E Vac Tubes

Have had an array of issues. Most of which have been failure right out of the box. Have used Viessman, Thermomax and SPP. I have switched to flat panels and have been suprised at the output and have enjoyed the durability.

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tim smith

Thanks Paul, Bob & Eric for your replies.

Thermomaxx is what I have been looking into. Appreciate the inputs.

Bob Gagnon plumbing and heating

Evac Tube Failure

Like Eric, I too am suprised at the performance of my homemade flat panel collector. It outperformes my evac tubes at low temperatures. I think a copper based flat panel sould last many decades.

Thanks, Bob Gagnon



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marco_5

homemade?

i'd love to learn more about the homemade panel, can you provide details?

Bob Gagnon plumbing and heating

Homemade Solar Collector

I made this years ago with leftover baseboard element painted black, I didn't know about reverse return back then. I bought special glass that lets the maximum amount of ultraviolet rays through. A few years ago I had the loop turned off by mistake in the winter, it was nearly zero outside and the anti-freeze in the collector was over 200 degrees. It is a custom box 4' by 22' that also acts as an awning to keep the sun and heat out of the house during the summer, but allows the lower winter sun in during the heating season. I tell people that it is a solar interceptor, not a solar collector. At the lower temperatures I use for space heating this thing really harvests a lot of energy.

Thanks, Bob Gagnon



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hot_rod

finned tube collectors

much like the old SunCatcher collectors out of Huntsville, Alabama. Allegedly designed by some former NASA engineers. I've removed and resold over 100 of 20 year old SC's from apartments in Arkansas.

hr

Brstr

Viessmann Evac Tubes

Thermomax still manufactures the 300T Evac tube to Viessmann standards in Great Britian.

Plumdog_2

Suncatcher

Were those the ones that had a parabolic trough with a finned tube at the "focal" point, and rotated from east to west during the day? I copied that design one time about 1985, and it blew the relief valve in about 20 minutes. But I think it's a good idea..they can turn back away from the sun when too hot.

hot_rod

just a flat panel, those SC's

odd size 6.5 by 3.0 feet. the absorber looked a lot like AC condensors, 1/2" od tube connected to 1" headers.

hr

SolarBob

Solar is Hot

I have installed five Thermomax evacuated tubes systems, a total of 190 tubes in the last five years, and at last check  there are 12 failed tubes. Very disappointing. You can tell the vacuum has been broken when the metallic underside at the top of the tube turns a frosty white color. Kingspan Solar, who purchased the bankrupt Thermomax told me it wasn't their problem so me and my customers are "out of luck".

I believe their glass to metal vacuum seal isn't up to the task.

I have been doing solar thermal for thirty years and I have switched back to flat plates, exclusively.

We could debate the efficiencies and the cost effectiveness of the two, but to me, the longevity factor clearly favors the flat plates

If you want to see a real time comparison of AET Solar flat plates and Thermomax evacuated tubes go to www.solarishot.com

One thing I can say with certainty is that I will never buy another Thermomax tube and that if Kingspan has solved the problem and is making a better tube then they should step upand honor Thermomax's warranty claims or they will soon be alongside them.    

Simply Rad

Broken vacuum tubes

I have about a dozen Viessmann Evac tube systems in the Colorado mountains.  I am extremely frustrated with the failure rate.  I have been replacing on average 30% of those tubes every year.  We have even been replacing the tubes we have already replaced.  I have spoken to other installers that have used Apicus, and they have had failures also.  I know a lot of people are talking about the tubes and how they have had good luck with them.  I ask, have they serviced the system to see how the tubes are holding up.  Most just want to argue how well they work in the laboratory



Yes they work very well, but not if they are broken,  I have only been installing Flat Plates for the last 4 yrs. since I found the Evac tubes to be flawed.   Shouldn't we be installing materials that last?  Flat Plates have been around and working for many many many years.

Simply Rad

Broken vacuum tubes

I have about a dozen Viessmann Evac tube systems in the Colorado mountains.  I am extremely frustrated with the failure rate.  I have been replacing on average 30% of those tubes every year.  We have even been replacing the tubes we have already replaced.  I have spoken to other installers that have used Apicus, and they have had failures also.  I know a lot of people are talking about the tubes and how they have had good luck with them.  I ask, have they serviced the system to see how the tubes are holding up.  Most just want to argue how well they work in the laboratory



Yes they work very well, but not if they are broken,  I have only been installing Flat Plates for the last 4 yrs. since I found the Evac tubes to be flawed.   Shouldn't we be installing materials that last?  Flat Plates have been around and working for many many many years.

Kevin_in_Denver_2

Thermomax Has a Glass to Metal Seal

Some of us are unconvinced that it will hold up over the years.



The double wall "Sydney Tube", however, should be more robust.

JethroPettit

faulty batch of Thermomax vacuum tubes

Hi, I see from this thread that I am not the first to experience Kingspan's refusal to replace faulty Thermomax tubes. My entire array of 20 tubes lost their vacuum within 4 years of installation, and the supplier is convinced it was a faulty batch, but says that Kingspan will not replace them. Has anyone had any luck with this? I live in the UK. Thanks.