WM Ulta and Viessmann Vitodens

Kal Row

seems no one directly answered your question

>> WM Ultra and Viessmann Vitodens, any good?

Yes: they are BOTH very good, and they both will save you money, even if installed incorrectly - believe it or not - and yes, even though it might not make sense as to why a bad fit should even work, let alone save - maybe because they both have outdoor reset - or that their fires are just burning better - they just do!!! –

but based on the last quotes i got, the Vie$$mann is about one thousand more than the ULTRA - so you might need to get into each one's science - and your load’s specifics - if you want to choose intelligently between them

John Ruhnke

AFUE is a big JOKE!!!!!!!!!

AFUE is a BIG JOKE!!!!

Afue is a very bad prediction of boiler efficiency performance on a installed job. AFUE works great on the test that they designed back in the 50's. Besides combustion efficiency is a very small part of the over all efficieny of a heating system. What about cycle times and length? Water temperature at the boiler and out in the system? Heat transfer from the heat emmiters to the room? AFUE doesn't take any of this into account. I saved my parents 28% in fuel bills and it wasn't just do to combustion efficiency. DOE is a big joke too. All they want to do is fund some politicians campaign contributor. They could care less about saving energy. They are totally clueless and don't understand how anything works. I talked to them, submitted a grant too them and all it accomplished was for me to realize just how stupid they really are.Why do you bother to rely on AFUE to judge the efficiency of your heating systems?

John Ruhnke

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Constantin

Fascinating Rant

While I agree that any organization has improvement potential, the characterization that the DoE is run solely by a bunch of stupid political lapdogs does not square with the four years of experience I had doing work for them. Besides doing the reverse engineering on washing machines, residential AC, and water heaters, I also helped the DoE make funding decisions on new technologies like fuel cell designs, new solar manufacturing processes and the like.

In other words, clueless people like me may not have seen the brilliance of your design when you submitted your grant. I'm sorry that didn't work out and I agree that some government labs get more research work than the quality of their work merits. However, there are some very smart folks working in DC to allow us to save energy by raising minimum efficiency limits.

Consider the constraints that Congress has put on the process... they are the main reason that things are as difficult WRT grants... and why it takes as long as it does to come up with a new efficiency standard. Perhaps if you understood why getting a new standard approved is as laborious as it is, you wouldn't be as flippant about the shortcomings of the AFUE standard.

Remember, the standards-creation process is something that all suppliers to the US market get to have an input on. What makes AFUE so appealing is the simplicity of the test. Consider the alternative, a standard that not only tries to capture "real life" efficiency across a "typical" heating season, but one that also accounts for the types of heat emitters being used.

For the new standard, you'd first get to come up with a reference heating "season" the way the SEER standard already has. That will be fun. Remember, this has to be the average across the entire country...

Then, you'll probably have a different efficiency with each type of heat emitter. Steam systems don't condense the way radiant floor systems do... and how do you account for responsiveness, etc. ? What about the electrical load of the balance of plant? What should be a reference BOP design?

Nevermind the pyrotechnics you'll unleash WRT the manufacturers. For most of them, this is a commodity business with very low margins. They have no interest in raising their cost base and may elect to cull marginal units rather than certify them to a new standard, particularly since each heat emitter type will probably require a different test setup. I don't think that US consumers are necessarily served anytime we reduce the number of equipment choices for them.

So before you relegate AFUE to the trashbin, consider implementation. The test has to be simple, cheap, yet relatively comprehensive. I believe that the net outcome of many energy efficiency debates that have raged here is that AFUE has its flaws, but we understand them. A more holistic standard would be great, but invariably it too would suffer from the idiosyncracies of what it is, a standard that may or may not reflect reality as well as it should.

Ken_8

Say what?

"Why do you bother to rely on AFUE to judge the efficiency of your heating systems"?

I'll tell you why John. Because with all the alleged and specious AFUE "shortcomings" we are sick of hearing about, it is still the only reliable standard we can trust to compare one boiler to another.

I find it humorous that those manufacturers who do not fare as well as they would like in the battle over AFUE's, complain about their notion of "unfareness" the loudest.

What does that tell us? Is the AFUE test criteria "standard" to blame? Or, is it the corporate marketing forces whining about their mediocre results - because they are unable to get ratings that would benefit their self-serving desire to make it appear they are superior, when in fact they are not?

You don't suppose THAT could be the reason for all the whining now - do you (:-o)

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John Ruhnke

Reality

Ken,

I am not interested in false predictions of combustion efficiency. That is what AFUE does. I am interested in actual combustion efficiency in the field. When I tune my boilers, I tune them to save my clients energy. I tune the boiler to have the lowest oxygen content in the flue gas and other things. I use my combustion anylizer, a Fyrite Pro. The boilers that achieve the best efficiency, like the viessmann and Buderus don't score high on the AFUE. They also have every right to complain because they will save you a lot of money in fuel bills. Other American boilers may score a higher AFUE but cannot be tuned very well, like the old hydrotherm I tuned last year. The hydrotherm had the worst efficiency that I ever saw yet it had a high AFUE. If you tune to manufacturer specs you will have a boiler with good AFUE ratings but the boiler will cost your clients lots of money in fuel bills. AFUE is a joke because it does a lousy job of predicting fuel savings once installed in the field. Engineers have been telling this to people at the DOE for many years. Yet they refuse to believe.They waste billions and billions of dollars of the tax payers money on fuel bills and development of technology. I call that stupid. What do you call it?

John Ruhnke

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John Ruhnke

I did my job, I submtted a solution but they rejected it.....

I don't want anyone here to tell me I can't call the DOE stupid. I worked very hard and came up with a great solution. I submitted it as a Grant to the DOE. I guarantee that my project would have saved this country billions in fuel bills. They rejected it in the first round, They rejected it in every category. They said that I would be a very bad business man, that the whole project was completely bad. They basically took two very long pages to tell me how stupid they thought I was. I CAN SAVE THIS COUNTRY BILLIONS IN FUEL BILLS. Don't tell me I cannot call them stupid. They are stupid. I am very very mad.

John Ruhnke

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Ken_8

John,

You missed two very significant points.

Those being, NO ONE FORCES A MANUFACTURER TO SUBMIT TO THESE TEST STANDARDS !!!

AND NO ONE FORCES THEM TO PUBLISH THE RESULTS OF THE STANDARDIZED AFUE TESTS EITHER !!!

Off the top of my head I know Monitor/MZ for years didn't bother. They also make one of the finest pieces of equipment on the planet.

I too had a rejection on a fuel saving device of my own design. My design would also have saved billions of gallons of fuel oil and billions of cubic feet of gas as well.

But compared to simply turning every thermostat down one degree in every home in America for an entire heating season - my design was a joke.

I know the feeling of rejection. Just ask my wife (:-o)



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Mike T., Swampeast MO

I'm probably causing much of the confusion

as I'm confused myself. Sorry.

I'm trying to find out how the built-in variable speed circulator in the two smaller models functions when a low-loss header is used on a gravity conversion system with TRVs.

Manual states that the circulator modulates on outdoor temperature and "activation period" of the normal and reduced heat settings. A different circulator mode is menioned (once by name--not described) when the low-loss header temp sensor is installed. Modulating on outside temp is quite different than modulating to keep boiler side flow less than system side flow. Not a problem unless your typical system maintenance flow is 3gpm or less but open a TRV or two and system flow jumps multiple times.

John Ruhnke

Copper, PeX

Ken,

I remember the old copper pex debates of the past. Actually I have a lot more respect for copper radiant systems now. I have worked on 60 year old copper radiant systems that have never had a leak. Also the heat transfer is better with copper. Don't get me wrong, I still like and install PEX. You are always up for a debate. Debates are good though. I learn a lot from getting involved in them.

WE can do better then AFUE. I am just trying to wake some people up, that is all. Jim Davis has taught me a lot on combustion efficiency. The stuff I learned from Jim showed me that we needed to come up with a better standard for heating system efficiency. I invented a better standard. I am just frustrated because I have a hard time getting people to see what I have. I am not mad at you. I am mad at the DOE.

John Ruhnke

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Unknown

varies

The pump varies based on temp based on outdoor tem, then looks at rate of rise to rate of fall in the LLH, then it looks at the Delta T of it's own supply and return, then it looks at O2, CO2, NOX and adjust the burn, speed of blower, speed of circ all based on this information.

clear as mud yet?

Unknown

Ken and John

Before anyone here decides to throw the baby out with the wash water, why not punlish here the exact test procedures that determine the AFUE. You know the ones I am talking about that include measuring the Delta-T between Ambient Air and Stack temp. The less difference the better the AFUE. Now in Viessmanns model you take a 100F exhaust temp and compare that to a 70F room temp, in Big Tans corner you take all the insulatioon off the boiler and run it flat out, making the room 250F compared to a 300F stack temp.

Amazing how they can both get the same AFUE rating isn't it :-)

wheels

PS - john, never give up your zeel to have world peace. There are pople who believe in your quest!

Ken_8

I understand your frustration...

I simply suggest any standard is better than none. The old method, which was REAL nonsense, was inverse logic at its best. Know what goes in, in fuel potential BTU's. Subtract stack loss. Calculate standby losses. Come up with a number.

Done. It was called, the DOE method. It was extremely reliable and repeatable. But they (and we) realized the numbers meant nothing other than a set of standards that measures efficiency during a small portion of the time equipment is in use. Namely, when it was running. Since heating systems are off most of the time, the actual efficiency must be measured for both the on time - and the off time to get a true efficiency rating. AFUE addresses that nuance rather nicely IMHO.

Now we have critics suggesting that too, is a bad way to develop a standard. The critics have a point. But it is not based upon some vague or inherent inequities of the AFUE test standards. It is based on the fact that the stndard does not put their product in the best possible light!

There is nothing that prevents these marketeers from providing the AFUE number based upon the national standard which is universal - and then posting another AFUE number with an asterisk (*), and developing a concensus "standard" all the high-end and super efficient boiler makers could accept and agree on; and use the AFUE* as yet another "standard" and more to their liking.

Don't hold your breath on that one. They all **** about how the AFUE "standard" is so bad, but no two could ever agree to some other method that is fairer than what we already have.

The reason there will never be an AFUE* concensus? Because their complaints about the standard AFUE is based on marketing - not engineering/science - and each complainer would want the testing done to maximize their particular product, to get the highest conceivable AFUE* number - and then go out and sell the number as if some Holy Grail.

With all its shortcomings, AFUE is as good as we're going to get for now. AFUE*? In our dreams only, I fear.



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Mike T., Swampeast MO

That Sounds Quite Clear

If complicated...

Just wish the English language manual was the same. Would be very reassuring if it said that the circulator speed with low-loss header was dependent upon all (or which) of these variables--not just outside temp and timer state for "normal" or "setback" mode...

Found the German .pdf document for that circulator but nothing similar in English.

Translations get things like:

Heizkreispumpen-Kennlinien Durchflusswiderst

Kal Row

dont blame da boylah

if this HO uses propane - he's out in the sticks, and his water's PH is all wrong for the new fangled suff

i bet that kind of evironment is going to give the WM ULTRA's the most grief - will just eat the aluminum HX alive, WM just cant make people install it right with correctly maintained PH - this is how a reputation goes down the tubes

for these envs, a CI boiler with pri/sec/injection a-la a tekmar 362 is the best fit

Ken_8

Guess again.

The "sticks" does not automatically = low pH laddie.

My spring in VT produces soft water and the pH is 7.1

Almost all river and lake sources will be soft and 7.0 or greater.

I'm sure you were just generalizing right?



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hr

The boylah or

girlah didn't fail, all the components did.

The water was balanced and CP-3 added, maintained, and tested from day one. I feel the chlorides present more of a challange to stainless than ph, by the way. See the acceptable levels in virtually every stainless tank installation manual.

Crown has stickers on the outside of their stainless indirects with the caution.

I say softened water users beware, an improperly adjusted softner brine cycle and or rinse cycle can lead to elevated chloride levels. According to local conmmercial water treatment folks, locally. Do you check all your softner installs? I never have

Around here stainless is used in food processes to handle vinegar, tomato slurry, and mustard. Properly selected stainless grades are the norm for ph problematic "stuff".

Ph will be more of an issue with aluminum, as the manufactures of that equipment caution. Pay attention to their tight ranges regarding ph levels.

This unit had an unending appetite for ignitors, circuit boards, one gas valve, 1 update burner kit, one complete burner (new style) replacement, and the list goes on.

LP regulators (two stage)changed, data logger installed on incoming power. I hired another expert condensing troubleshooter to check my work and settings.

I just plan ran out of options.


Ironically I installed the exact same LP unit within several miles of my shop within months of this one. To date 3 ignitors and, one blower motor with failed bearings, and an update kit on that one. Although now I have a spare parts sourse

Both were combo units suppling DHW and radiant and they run virtually every day to provide DHW.

I still have confidence in the manufacture, and continue to buy their other products They spent hours on the phone, even on Saturdays, trying to troubleshoot the issues with this unit. Guess I, and my customer, just got a lemon.
Chalk it up to bleeding edge technology.

hot rod

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Mike T., Swampeast MO

Extra cost and maintenance aside, with one of the smaller Vitodens with variable speed circulator modulating on outside temperature [and maybe more variables as well] driving a one-pipe b/b loop won't that mean that velocity will decrease and delta-t will increase considerably during the most common weather? Your supply temp may still be kind of high, but return should be nice and low...

Of course it's going to require a well-engineered system to begin with that's not sized by the "wall to wall" method...

A wall t-stat seems to be an accessory on the Vitodens.

Kal Row

i was generalizing ken, and hot rod...

i just love your maintenance log cant ever get lost - except of course, when they throw unit out - oops - there goes all that colorful history...


Anyway, all systems with combustor fans are going to fail more - "we are not in Kansas anymore" - but the superior combustion makes it worth it, usually... i get and include spare parts like that in my original price - with the approach of asking for spare part stocking recommendations, the manufactures are usually forthcoming about the failure rates - i put GFI's and surge protectors in also to protect the electronics from thunder storms.

Glen

Ok -

So you want a LLH interfaced with a gravity heating system. This will work as the LLH is a hydraulic decoupler, eg the vitodens may decide that a boiler through flow of 3 gpm is required while your system side is moving 12 gpm. This happens in the LLH by a counterflow mixing. As you are gravity you don't even have to worry about pressure and flows spikes when a trv or zone vavles closes. It should work fine. I would though try to buy the Viessmann 2 inch (2 inch BSPT) low loss header - it's quite a bit larger than the 7134 230 model and would offer very little flow restriction for your gravity system.

Mike T., Swampeast MO

Actually without the low-loss header. It's when the system flow is low when the TRVs are modulating--like 3 gpm or less--that I wonder what will happen on the boiler side.

Glen

Still OK -

The temp sensor normally located in the LLH would then be in your supply piping header - right?! The vitodens uses this sensor as the target temp as programmed by you within the heating curve menus. While the boiler doesn't really measure flow - it measures temp rise or fall within the boiler envelope and then adjusts firing (modulation) accordingly. If flow is low and temp rise high - I would expect minimal firing or none at all. I am curious though - as to how you are piping the boiler into the gravity system - my fax here 250 489 3796. Howsabout a picture. (I may not reply until Monday - within moments - I'm hopping on the Goldwing for a buzz around the Rocky Mountains of BC and Alberta. Banff, Jasper, Columbia Ice Fields etc.)