Buderus Logasol SKS 4.0-s flat plate collectors

Lerch

Several years ago, we installed a wood fired boiler in our home. Our plumber suggested using a larger storage tank, and recommended the Buderus Logalux SM400 tank, which I've since learned is intended to be used with, but may be used without, solar flat plate hot water collectors. Buderus made the Logasol SKS 4.0-s flat plate collectors, and an associated "solar pump station" or "solar station", and said components can be connected to the lower internal coil within the SM400 tank.

So, I kept my eye out for some solar collectors, hoping to add this functionality to our system. This past winter, I found a pair of collectors, and associated pump station, in nearly new, never used condition, and purchased them for next to nothing from a plumber who had intended to mount them for a customer but who abandoned the project.

Now, I'm eager to install, but am finding that Buderus discontinued this line of products, and they have NOTHING available, at least here in the USA. Stunning to me though it may be, I haven't given up hope. Perhaps someone on this forum can point me in the direction of parts for this system? Are parts still available in Europe?

Of most interest to me is obtaining the mounting kit for attaching to a roof. My research indicates that Buderus made two different mounting kits for these collectors, one intended for sloped roof installation, and the other for flat, or nearly flat, roof installation. As I'm still in the process of selecting where to mount the collectors, I'm not yet sure which style of mounting kit will be best.

Any advice or suggestions would be much appreciated.

hot_rod

I can maybe help, I still dabble in solar thermal stuff. Got a pic of the side of the collector to show where the mounting connects.

Noel

I still can get all of the old literature for the Buderus solar stuff, if you need any of it. The equipment is long gone, though, as you discovered. I'll look into what I can find on the mounting hardware tomorrow. Noel

Ironman

hot_rod said:

I can maybe help, I still dabble in solar thermal stuff. Got a pic of the side of the collector to show where the mounting connects.

Bob, the Buderus panel has a unique mounting: there's an extruded lip around the entire edge of the panel where a clip screws down and attaches it to the aluminum uni-strut.

hot_rod

looks like a special piping connection also?

Ironman

Yes, the stubs are metric, 12mm I believe. Some have made the mistake of using 1/2" copper or Sharkebites on them.

Getting the connection hoses/kits is gonna be a problem for him.

Ironman

I emailed you the applications manual. Can't seem to find the install manual. You might try the literature archives at Bosch.

Lerch

Thanks very much for the replies. I am sorry I am only now seeing and responding to them.

This situation I am in sounds rather discouraging. I gather you guys are in Europe somewhere, and had hoped that perhaps you'd know of sources. I'm not giving up yet though. Any leads are much appreciated.

First off, I've changed my notification preferences, so hopefully should be able to see and respond sooner now.

Secondly, I sent a request to Bosch customer service in Europe and hope to get a response.

Sounds like I may have to engineer a solution myself if I'm going to make use of this equipment I have.

Lerch

Ironman said:

Yes, the stubs are metric, 12mm I believe. Some have made the mistake of using 1/2" copper or Sharkebites on them.

Getting the connection hoses/kits is gonna be a problem for him.

Ironman, I am in USA and not familiar with metric fittings. Is there a commonly available fitting that can be maden (perhaps with some modification) to attach to this (12mm?) stub?

Lerch

I have two installation manuals - one for sloped roofs and one for flat roofs. I just read through the sloped roof manual, and I see this isn't going to be easy. Between the roof hooks, the horizontal rails, and the panel connection brackets, this is quite a system. I'm going to have to look more carefully through what I have.

Ironman

12mm is slightly smaller than 1/2". But don't try to use American fittings.

The Buderus connection kits have double O rings the slip over the stubs and a SS clip that retains them.

Some years back, we went behind another company where the knucklehead had used Sharkbite fittings instead of the Buderus connection kits and they were leaking like a sieve. We end up replacing 8 panels.

I really hate to tell you this, but unless you can come up with the proper mounting hardware and connection kits, those panels will probably be useless. And if you can find the right components, you may spend more than if you bought another good brand of panel like Caleffi. Then there's the issue of future component failure and no warranty.

hot_rod

I know some Buderus reps that may have some connection kits, I'll ask around.

There are some work arounds if you want to go rouge

Lerch

Bob Boan, your advice is noted. I'm not inclined to make sloppy connections. I want it to be reliable or I don't want to do it. I also want it to be reasonably economical.

Bob Rohr, I would be grateful if you could locate a connection kit for me. I'm also willing to consider work arounds.

Lerch

What do any of you know about why Bosch chose to get out of this market? Economics drives many of these choices, and I suppose the economics weren't good. Still, there are some solar panel companies that remain. Did Bosch have technical problems with the Logasol system? How many years ago did Bosch discontinue the Logasol system?

Ironman

Strictly economics. The panel's and components were high quality. They're still sold in Europe.

Before Bosch acquired them, they had plans to move the manufacturing to Tennessee because that's where the best glass comes from.

It took me well over a year, and going directly to the VP, to get some replacement panels under warranty a couple of years ago. They had to be shipped from Europe as there were none in the US.

Lerch

Ironman Bob,

Thanks. If the panels and components are still being sold in Europe, does that mean that I can still buy a connection kit in Europe?

Al

hot_rod

What type of roofing, how many collectors? Do they need to be raised at one end, or right on the pitch of the roof?

Mounting could be fairly simple. We had kits for the Euro style mounting, it may not be exact. I'd be glad to send one to try.

A chunk of aluminum and hack saw could build a grooved bracket The one in the pic is aluminum bar stock with a groove milled in.

I use basic aluminum Unistrut, available from FasteNal, B-Line or unistrutohio.com online.

Really it doesn't take much force to pinch the panel to the strut. The bigger force is uplift and shear from wind and snow, so the clip needs to be thick enough to handle that force. If you pitch the collector up on one end, of course wind shear potential increases.

I'd mount them to the pitch of the roof, take a small efficiency penalty. They look better, easier to mount, and wind load concerns go away without legs and cross bracing, etc.

Here are some mount examples.

I know the company that built those connectors for Viessmann and Buderus in Germany, I'll ask him for any thoughts. No go on a kit from a Buderus rep I known in Washington. Noel up above should be able to help with Buderus contacts. The Colorado guys were solar proponents, look there also. I'd bet someone has some kits on the shelf. Go to the Buderus site and get contact info for all their US reps, send an e-mail as a first step.

You could just expand the tube on the collector and solder 1/2" copper, .375 OD into the 12mm .472 OD, it doesn't take much to get them to match. Depending on the wall thickness of the 12mm, .9 or 1.2 mm wall thickness typically on 12 mm copper tube. 1/2" copper may fit without much work, try a piece of 1/2 copper, see how it matches the 12 mm. possibly you expand the 1/2 copper to fit tight inside the 12mm.

A glob of hot Dam around the tube to prevent heat damage to the collector or rubber grommet, if you solder. Once you get to 1/2" copper, all sorts of connection options.

Compression couplings are easy for connecting collector to collector. Compression coupling to adapt to the copper you run to the pump station. If you do solder 95/5 or 97/3 solder is best.

You can also find 10mm to BSP or NPT thread adapters online, quite $$ generally.

Really depends on how creative you want to get to use those collectors.

Lerch

Hot rod Bob,

Awesome info, thank you so very much. In terms of mounting I've got a couple of options. One option is easiest in several respects, mounting on a nearly flat metal roof, closer to the storage tank and pump station, but would require a stand bracket to incline it from the roof. Solar exposure is OK, but not great.

Another option, which has better solar exposure, and as you point out is less subject to wind loads, is to mount the panels above the attic on a sloped roof (9:12 rise:run) with 3 tab asphalt shingles. The roof faces south, with existing trees blocking some of the afternoon sun. The efficiency penalty seems a minor issue. It is further away from the storage, But there is ample space in the attic to install the piping and no substantial conflicts in doing so.

I've got 2 of the Buderus SKS collectors.

I'm going to study your post. There's alot there. Thanks again.

Al

hot_rod

Solar south at your latitude is ideal mounting position. A few degrees off in either is not a big deal. Vertical walls are an option also.
Where are you located, I can run a quick simulation to show you what to expect.
If the cost was low and installation is not too costly, you should see a good payback.

I doubt you have warranty on the collectors, so some imagineering modifications should not be an issue.

Lerch

All sounds good. I am located in Great Barrington, in the southwest corner of Massachusetts, USA. Latitude here about 42.2 degrees. 9:12 roof is 36.9 degrees. Difference of about 5.3 degrees. I suppose some efficiency might be gained by tilting upper edge up by that amount, but seems minimal.

Open sky all morning. Trees begin at about 3pm afternoon sun. Leaves are down in winter and so trees have less effect then.

My preference is to find the original hardware I need, at a reasonable cost, but if not available, or if exorbitant, I'm inclined to make something to do the job.

Correct, I have no warranty option available to me, so am not worried about voiding a warranty.

hot_rod

My database did not have your town, I used Vermont as a comparable. It did have your collectors and tank, I assumed 60 gallons per day 125°. South facing @ 30°.

Solar fraction of 55%, meaning it will offset about 55% of your DHW needs.

As to why ST solar thermal is not in Vogue currently...
Fuel prices, LP is at $1.24 per gallon here today
Incentives from Fed and State, local utilities, etc have dried up
An administration not promoting renewables, as in "windmills cause cancer"

Ironman

@hot_rod
Bob, I wouldn't recommend trying to expand the copper nipples on the panels. They are thick, hard drawn and I don't think you could heat them hot enough to anneal them with out burning up the grommets that seal them. They're also in a pocket up under the glass so anything with a torch (especially for an ameture) is risky.

hot_rod

Ironman said:

@hot_rod
Bob, I wouldn't recommend trying to expand the copper nipples on the panels. They are thick, hard drawn and I don't think you could heat them hot enough to anneal them with out burning up the grommets that seal them. They're also in a pocket up under the glass so anything with a torch (especially for an ameture) is risky.

Good point.

Another thought is go to a UK website like Wolseley. They are the parent company of Ferguson here in the US possibly the largest supplier worldwide. I'll bet you could find the correct parts from a them or another Bosch dealer overseas.

A machinist could easily bore a tube with an O-ring to fit, the clip o hold it together would be more of a challenge.

Always a way to connect tubes, once you set your mind to it.

Lerch

The collectors I have are still in the original packaging, with the plastic corner caps containing the between panel connections.



I now understand the connection method. I gave it a try. Cool design.

I used a vernier to measure the outside and inside diameters of the tube stub. I consistently measured an outside diameter of 15.65 mm. My measurement of inside diameter varied, probably because of my lack of skill in using the vernier for that purpose, anywhere from 12.79 mm to 13.08 mm. In the end, I'd say the inside diameter is about 13.0 mm.

hot_rod

So you only need two connection adapters? Taking the piece you have to a machine shop to make a brass adapter is an option if you cannot find the right flex connector.

I tried two dealers I know without success.

I'm almost certain my friend Solar Kurt in Germany builds those adapters. I was at his shop once and remember seeing boxes of Viessmann, Buderus, Baxi, Wagner most every Germany solar manufacturer he built adapters for.

Expensive getting stuff from Germany, might be cheaper to custom build a few adapters.


https://www.solarmetalflex.com/en/

Lerch

I think that is correct. I believe I would need to make the main in and out connections, and I might have 2 leftover of the inner connection pieces pictured, if they might be adapted.

I looked at your screenshot and that looks like a good source, but I can't identify it.

The tube stub looks like brass or bronze to me, but I'm not well versed in how to identify. I looked up metric tubing sizes and it looks like it is typically sized by the OD. I measured 15.65 mm, which doesn't seem like a good match. Do you know if this tubing is of a standard type, or if it is a custom diameter?

Lerch

Hot Rod,

Now I see the link. Thank you.

Al

Ironman

Those are the couplings to use between the panels when they're close -coupled. The SS retaining clips are used an all connections.

If a machine shop could make a sleeve to hold the O rings with a shoulder for the retainer clip, you'd be in business. You'd want a flexible connector on the other side that's 1/2".

hot_rod

If you have an extra between the collector connector, here is another option. Cut it in half and braze copper inside or outside it. This is basically how the factory builds the flex transition piece. You should be able to find copper that fits into or over the flex.

HVAC/ AC guys tend to be better versed at silver soldering, and have the torch and solder on their trucks.

Tinman

Wow! Great service, Bob and Bob! Ironman and Hot Rod crushing it.

Ironman

If you come up short on the flex couplings, I’ve probably got a couple that you can have.

Lerch

Thanks very much for all the help and great advice. I'm going to do a detailed inventory of what exactly I have, and will post back. I think I do have extra between collector connectors, and I like the idea of cutting in half and soldering.