low-loss header question

[Deleted User]

How highly do you value it?

If you weren't standing there soldering tees together, could you be doing something else more productive, making even more money for your company?

How skilled are you at determing the minimum distance between tees and elbows? It matters...

How much wall space do you have to be able to fit this whole shebang into?

Some manufacturers (Viessmann) would prefer that you do it this way because it has a LOT to do with the thermal performance of their appliance. Other manufacturers (Buderus) do the math for you and provide a P/S header prefabbed. It doesn't HAVE to be used, but it keeps you out of trouble and keeps their appliance doing what THEY want it to do.

That said, Viessmann is NOT the only manufacturer of LLHers.

Look at Caleffi, and Radiant Engineering.

The concept is quite simple. THe application is brilliant. But they don't make sense for every person nor every job. Kinda depends...

ME

Unknown

why buy

a $400+ one (a la Viessmann) when it would appear you could easily make one for a fraction of that out of copper tees? or am i missing something?

Unknown

good points

but that said, how do you you know when a LLH would be a better fit than a P/S arrangement? i haven't found any application info on them aside from what i've read in the Vitodens manual.

bob young

sub out complete job

it is excellent for morons who do know how to design & fabricate one. why don't they let the manufacturer do the complete installation and get over with it.

Unknown

to put it bluntly! ;D

yes i guess thats true too...

but there must be some design criteria on assembling them from scratch?

Constantin

Huh?

it is excellent for morons who do know how to design & fabricate one. why don't they let the manufacturer do the complete installation and get over with it.

Bob, besides the unfortunate choice of words, I believe that you left out a negative somewhere. As it stands, only "morons" know how to fabricate a LLH.

You seem to think it's very easy, Mr. Eatherton seems to imply that some thought has to go into it. Given that the Wall is a educational environment, why not illuminate for the rest of us what goes into the design of a LLH, such as sizing, port locations, etc. ?

As for Zacs initial question, I think a LLH is more than a few closely-spaced T's. For example, if you look at the design and construction of the LLH's made by caleffi, Radiant Engineering, or Viessmann, they all offer a much larger pipe diameter than what the primary loop is made of (something like 2-3x) and they also have the intakes and exhausts spaced far apart and across from each other, unlike closely-spaced T's.

I believe the intent of a LLH is to enable a complete hydraulic separation of the boiler from the primary loop while still allowing very good mixing and heat transfer. In other words, pretty much anything can go on in the primary loop and the boiler will still get the flow, etc. that it needs to operate safely. LLHs are a great idea for heat exchangers with a high pressure drop and they also make excellent locations for expansion tanks and vents.

While it is possible to fabricate all of that out of bits and pieces, the question of why one should arises when people already make pre-fabbed, leak-tested, etc. assemblies that you can plug in and forget. I guess it comes down to how much you value your time.

bob young

learning process

nothing like starting the week getting both an english lesson and professional direction . i will definitly take your advice and stop all fabricating of pipe and use the manufactured products . this way they make the income instead of me. with all my extra time now i can study english so i can better communicate with homeowners that are obsessed with their heating systems. i realize i must mend my ways or i will never be successful. thank you very much for the lessons.

Simply Rad_2

Customer service?

Educating the cutomer what a great concept, they are the one's living with this really smart boiler. Now if you do it right, by using the manufactures LLH, you will be able to sit down and educate the customer. Now if you do it wrong, by trying to re-invent the wheel, you will spend alot more time fixing the mistake. Then, you will never be able to find the time or crediblity to educate. One, because you spend all your time fixing the sytem. Second, the customer at that point might have already opended the installation guide and is wondering were the LLH is. Do it right and you might find you'll have more time to relax, enjoy or even get more jobs.

Simply Rad_2

Customer service?

What a great concept-education. The customer is paying you to do it right, they are not paying you to re-invent the wheel, use the LLH. Why take the chance and do it wrong. If you do it right you will have time to explain to your customer how their really smart system works. If you do it wrong you will spend all your time fixing the system. In the mean time you will be loosing more time and credibility. While you are fixing it,the customer will be looking over your shoulder with the Viessmann manual wondering where the LLH is! Finally, think about what you can do with all this free time since you installed the LLH and things are working great-maybe you can relax for a moment and share a glass of wine with your happy customer. One thing for sure you will not have to go out looking for work, because that happy customer of yours is already telling everyone about his comfort system!
Jeffrey

ALH_4

And

Radiant Engineering is working on a new, slightly different design that makes piping cleaner providing two 1/2" FPT ports on top for the air vent and thermo-well and two 1/2" FPT ports on the bottom for the expansion tank and a drain. The LLH is an excellent place to vent air. Rarely is there a need for a Spirovent or equivalent when the LLH has a vent in the top.

There is absolutely no reason tees will not work. LLH's are a little cleaner looking than tees, and there are more options for ports than with tees. The operational difference is small... probably practically negligible. I do not believe that a sensor strapped on a pipe is as accurate as a sensor in a well immersed in the fluid.

-Andrew

Brad White_38

Radiant Engineering

I checked out their web site and it seems under construction. How does one get information on their products?

Thanks

Brad

EdyLogicMstr.

You have to know

how to read their minds;-)

Seriously Brad, you should e.mail Andrew WRT their stuff. They recently custom made another LLH for us with 1" tapings. Their website is currently receiving a badly needed makeover.

What are you going to be doing with that MZ?

Wallace Radiant Design

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

hr

The Caleffi HydroLink

takes the seperator concept a few steps further. it give you connection points for the secondary circs, air vent ability, expansion tank mount, and a nice solid mounting bracket.

Now the dollars make a lot more sense than just a 4 connection seperator.

Also a nice insulation package.

hot rod

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Brad White_9

The MZ is staying put, Gary

It heats the house and I have invested too much into making it the boiler it should have been in the first place. Added the buffer tank, their outdoor reset control (a Tekmar product) and balanced it to a T. Delta T.

The first year "therm use per degree-day" constant value was no different than my Burnham 204 with Centra 4-way control valve and OD reset installed in 1986.

The second year the buffer tank improved things. The third year the OD reset better still. Should have got a Vitodens but they came out a month after mine was installed.

Still, it is a good boiler, reliable and simple. But it comes in one stage.

Ron Schroeder

Hi Zac,

A LLH is more like a parallel P/S piping where a bunch of closly spaced "T"s is more typically a series P/S layout. Parallel P/S is usually better for multiple zones of the same temperature and Series P/S is usually better for multiple temperatures but either configuration can work either way with proper design.

Ron Schroeder

ALH_4

LLH

Adobe has added some nice capabilities lately. You might need to update your version to view this. This is still in design, though we are about to build a prototype.

-Andrew

Unknown

Siggy's 2003 artilcle on this subject

Beyond Closely Spaced Tees

Glad I re-read it.

Wallace Radiant Design

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Unknown

wow

that is way more info than i thought i would get, i think my brain is about to explode! (9_6) thank you all very much for the replies.

i was thinking of using a LLH on a geothermal in-floor system in lieu of a buffer tank, i think it may work!

Simply Rad_2

Zac

The LLH does not replace a buffer tank in a geo system. The buffer tank is used to keep the heat pump from short cycling and making sure it gets the longest possible run time. A LLW Decouples or separates different parts of the system. I would definately install a buffer tank in the primary loop. Jeffrey

Unknown

i've heard of GS heatpumps being used successfully for heating a single radiant zone without a buffer tank but it was done in series (a workmate of mine did it). my thinking was to improve on this by utilizing a LLH to accomidate the different flow requirements of the heatpump (3 gpm per ton) and radiant zone (say 4-8 gpm) its an experiment under controlled conditions, if it doesn't work i'll just stick with the buffer tanks.