What do you think of the Viessmann Vitodens 100 -824

Greennmann

Hi Everyone,

With a reset control that only gives and open/closed end switch output would that mess with the PID control of the burner?

My thought behind this is that the actual temperature vs time curve or line is compared to a constant temperature vs time curve or line which is a product of the aquastat setting on the front of the boiler.

In other words the burner always thinks it will be firing to the limit set on the front of the boiler and the its cut short by the PC700. So the burner would high fire more than it should and the longer run times at lower firing rates which equate to increased efficiencies will be missed.

What do you guys think?

Jordan_2

I always lusted after the Viessmanns

After thinking that a Viessmann boiler would always be way beyond my economic reach, I see that the Vitodens 100- 8/24 is now available at what seems a very reachable price. I have not been lurking lately but a quick seach of The Wall turned fails to turn up any threads about what I find very exciting offering.

Am I missing something that disqualifies this unit as a good deal. (Yes I know that its electronics package is pretty stripped down but my system doesn't call for anything fancy)

Love to hear from folks in the know.

Hugh

Paul Pollets

V100

We installed our first 3 weeks ago after doing more than 40 V200's. The V100 has no internal computer nor Matrix burner. It has 2 firing setups, one for DHW recovery for an indirect and a RT for the thermostat. It's really made for 1 zone of heating and the indirect tank. The low loss header must be installed if the DHW tank is added. It works well, but I prefer the V200. Having the outdoor reset control is what 21st century heating is all about.

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Hugh Mason

Paul,

Thanks for your quick and will though out reply.

Since we have but a single zone in our very simple yet comfortable system, might this be a match made in heaven for our particular system. We would be replacing a 20 year old Dunkirk XEB-2 cast iron boiler.

Hugh

scott markle_2

matrix x

No experience with it yet.

The burner/gas valve is not as sophisticated as the 200, but interestingly the dome shaped matrix-x that we have here in NA seems to have been fazed out of the european models. The new euro model burners seem to all be cylinder shaped like the 100 and have a refractory material at the back of the chamber.

I wonder how this refractory material effects cleaning procedure I have been using a citric acid based cleaner, would this be bad to get on the refractory?

The non matrix-x will not operate at as high of an altitude.

One potential plus to the 100 burner, I'm told that it has a different ignition sequence than the 200. The 200 lights at a high(mid)firing rate and modulates down according to required target temp. My experience has been that in low load/ low temperature (sub 100f) situations the burner sort cycles. Target temp. is exceeded before burner makes it to low firing rate. Apparently the burner is designed to handle this, the combi unit (same burner) which incorporates a dhw hx has to be able to do short burns because of the nature of hot water use.

The fact that the 100 lights on low fire and modulates up may be an advantage as far as mitigating short cycle in these conditions. Being able to control the boiler by 0-10v signal without purchasing anything, or discarding anything is a real plus if a third party control is used.

scott markle_2

0-10v

Paul,

I just assumed the 100 had a 0-10v contact am I incorrect on this? I agree that outdoor reset is crucial, but I have had real problems with short cycle on the 200 in my own house target temps are so low that under all but very close to design conditions chronic short cycle is the result.

Ironical my work around on this has eliminated temperature modulated outdoor reset and replaced it with fixed firing rate time interval outdoor reset .(tekmar 269.) My Boiler only modulates above lowest firing rate for DHW production. In heating mode I have drastically reduced cycling and have awesome sustained 30deg.+ deltas on supply temperatures that rarly exceed 113. Anyway this is really a subject for another post or a tech topic essay, I suspect that short cycle in low temperature systems( whether a boiler can handle it or not ) is the Achilles heel of full reset ODR.

Paul Pollets

control tabs

there are 2 LV settings....DHW for the indirect relay which will ramp the boiler to high temp to recover the tank, and RT for the room thermostat or pump relay. The RT setting will modulate the boiler according to the setting set on the main temperature dial. Nothing more, nothing less. If an ODR control were added, you're very close to the cost of the V200. This is a very simple control strategy. If the DHW tank calls, it will shut off the RT pump until the tank is satisfied.

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scott markle_2

Not providing a provision for third party control of burner modulation is a real shortcoming. I know of contractors who would not use the 200 because of the inability to interface Tekmar controls. Not providing this is a real failure to reach a broader market. Is a add-on (like the em-10 for the gb) available that will permit 1-10v interface? If not I'm very disappointed.

Brad White_184

Well, I do have to add

that the Vitodens was Viessmann's answer to bringing their retained quality down to a price-point competitive with a broader market. They traded features rather than sacrifice quality as I see it.

Agreed, you have to add in after-market accessories such as ODR but that is certainly achievable. What you do get is a very good heat exchanger (the same one as the 200 I believe) and very good burner albeit not the matrix burner. The circulator is also not included, certainly not the 200's VS smart circulator.

But if you have a basic heating need and want a quality ModCon in that price-point range, they offer it.

I just recommended a Vitodens 200 to a client who was also weighing the 100's features and benefits. The 200 was still more money (even after factoring in a Tekmar setup on the 100) but the 200 is an obviously superior, inclusive machine. The 100 still has my vote for when budget dictates spending a little less now and fitting it out later with better controls.

Funny thing is, in these discussions, many who start with a 100 want to turn it into a 200. It is not the same thing obviously. I can see the Viessmann folks thinking that there is no way to make us happy- we asked for a lower cost version then complain about the lack of features and that they march back in a different direction...

My $0.02 anyway...

Leo G_101

Hugh,

here is the solution that I came up with for ODR for the 100. We just went through colder then normal temps for Nov and the when I talked to the owner, he said the unit ran like a champ!

My max temp for design day for this home is about 120*F. So I set the heat T-stat on the boiler to fire up to about 115-120*F. (explained to the owner that if it seems to be getting to cool in the house, to turn the boiler control up a bit). With the modulation (as mentioned in another post, low to high), the boiler seems to get a very good burn time

The other interesting thing that I have noticed about this boiler is that it seems to have a 30 to 40*F delta T before it fires again, thus eliminating the short cycling that occurs with other mod/cons. I have been very impressed with the unit so far, and it is now the unit that I first quote.

It would be nice though if V had put more marks on the boiler T-stat, as the only mark they have is for 140*F. Also, the 0-10 control for this boiler is rumoured to be on the way. When that happens, I think that this boiler will become like the Wii, very hard to find, but in high demand!

Hope this helps,

Leo G

Ed_50

Ignition - Lo/High Fire

Scott,

The reason the 100 lights off on low fire is simply because it is only offered with natural gas. The 200, on the other hand, is offered with both natural and LP gas. Viessmann feels, due to propane's density, they should light off on high fire for a more stable ignition. At least, with the Matrix.

Paul Pollets

Exactly!

I was surprised when the Vitodens 100 was launched. The price difference seemed small when ODR was factored in. The need for a "competitive" condensing appliance drove the design.

The V100 does just fine for those who need a simpler system.

Who would add a tekmar to the integral Vitodens 200 controls??? Rather unneccesary. The Comfortrol was designed by Viessmann for the Vitodens. There is a modem setup for inclusion in 3rd party whole house system integration.

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Leo G_101

But Brad,

the 100 was brought out for those of us who wanted a simpler boiler that still had the highest quality, and we could use the controls that we liked. I am not trying to turn the 100 into a 200. I like that I can educate my customers on how to adjust something like the Taco RMB for their own personnal comfort parameters in a very short time.

There is nothing that compares to the 200, no doubt, but let's admit it, it is getting harder to find an opening in the Jet Propulsion Lab school these days. ~

My father taught me a long time ago to KISS! (and hug!!!)

Leo G

joel_19

100

WE have done a few of them Steve has 1 in his house and it works mint. You can have as many zones as you want. ODR is no problem with a simple Tekmar the little white 1 a 256 I think?? Works great on it for not much $$$. Has been problem free for us. Why would anyone want to put a Tekmar on a 200 though?? that makes no sense to me.

scott markle_2

No LP

Thats a real deal Killer for me, I was defiantly going to be looking looking at this boiler. Are you sure? LP seems like such an important market. Think of all the low density housing that exists in this county,and canada. If Viessmann wants to lead ( yes they do lead, but they need an affordable LP wall hung, with 0-10 and and set-point for heating and dhw, (like the gb)


The vito 200 is a great machine, but it's proprietary control package and price tag limit it's market share. I would miss the built in dhw solenoid valve and variable speed circ. not being built- in. But perhaps it's better to leave more options with the installer.Let them decide how to pipe: ECM cirs. or not, Primary secondary via buffer tank,LLH, closely spaced t's or direct connect... It all depends on the application. A versatile competitively priced multi gas condensing wall hung is essential to a more meaningful impact on the industry for this innovative and promising company.

joel_19

100

WE have done a few of them Steve has 1 in his house and it works mint. You can have as many zones as you want. ODR is no problem with a simple Tekmar the little white 1 a 256 I think?? Works great on it for not much $$$. Has been problem free for us. Why would anyone want to put a Tekmar on a 200 though?? that makes no sense to me.

scott markle_2

TN4

Comfortrol has low temp short cycle issues and no differential control.

tn4 is the other reason, this is a realy elegant combination of indoor/outdoor feedback and zone synchronization. Honeywell has recently launched a similar control system. for the high-end control this sensor based thermostat stuff is as good as it gets.

Rodney Summers

Joel

I am a little confused,How can a simple Tekmar 256 integrate to a modulating boiler? I didn't think it was so simple could you expand on how you use it,I imagine you will lose your modulating feature

thanks James

joel_19

100

The 100 modulates at whatever water temp you set it at so if it's at 160 it tries to modulate around that. An ODR will send it a water temp and it will modulate around that you are not hacking into the modulating burner programing at all.

rich pickering

Just fired a 100 this week. I've got it set up with a buffer tank, 3 zones of infloor and an indirect. 3 Taco radiant 3-speed pumps. Used 3 relays to provide dhw priority, and power the pumps. Even with the relays, my cost is cheaper than a Trinity. My only complaint so far is no peephole in the burner. As a service tech, seeing the HSI glowing is a quick trouble shooting feature.

scott markle_2

256

Joel, the 256 is intended for a non-modulating on-off boiler. This seem like a misapplication for the V-100. intelligent ODR with a modulating boiler must involve direct control of modulation. Trying to control supply temps. without control of firing rate doesn't sound like good design to me.

joel_19

100

You are not trying to control the firing rate the boiler does that all by it's lonesome you are simply controling the temp the water runs too , works like a charm for not lots of$$$.

Mike T., Swampeast MO

By varying the supply target, the boiler will modulate the burner. This is the same basic control scheme used by the Vitodens 200 and many other mod-cons. Even without reset, modulation will still occur--it all depends on the abilility of the emitters to liberate heat. If they cannot give off enough heat for any reason (undersized relative to boiler; not all zones calling, etc.) the burner will be forced to modulate to maintain the desired supply temp be it variable or fixed.

Of course with a fixed supply temp, you won't get the efficiency allowed by lower supply temps under lower load conditions nor or you likely to ever see extremely long firing times--think days if not weeks--that are common with well-sized, fully reset, well-adjusted mod-cons.

Giving direct access to burner modulation to outboard controls has many potential problems all of which are alleviated by simply giving indirect control of modulation via a target temperature.

scott markle_2

modulation

Outboard modulation control is hardly exotic and I'm not sure why you see this as being so problematic. A sensor is placed on boiler supply and based on the deviation from target the burner is modulated accordingly, yes boiler mass ignition sequence, speed of modulation response and differential settings are issues but these are all perimeters that can be adjusted. Maybe you have never seen a tekmar control operating a mod-con,I assure you they work beautifully. And offer load dependent differential logic that the vito-200 does not.

As far as modulation,Sure the boiler will modulate based on set-point, But unless the user plans to be constantly adjusting this setting it will most likely need to be set 40deg. above what most conditions will require, in-order to satisfy design conditions. This hardly leverages the low temperature condensing bonus that we should be designing our systems to optimize.

Using the an x-block, mix valve, or injection station to achieve full reset for radiant applications is a good work around for this boiler, but seems kind of redundant in a one temp. system. The boiler is fully capable of doing this on it's own, if only it had the instructions to do so.

It seems like the germans have thrown in the towel and given up on us with this. Not providing a modulation interface is insulting, do they think were just to to stupid to use it?

scott markle_2

Apologies to Viessmann

While I'm still disappointed that this boiler is natural gas only, I was relieved to see that an accessory for 0-10v modulation is available. It would be ridiculous not to offer this in my opinion.

Sorry to Viessmann and Viessmann fans for not looking into this for my self before getting all upset. You guys posting specific information about a products capabilities should probably condition your statments with an "I think"

Pdf for input module accessory is attached

Andrew Hagen_2

100

The Vitodens 100 would be great in this area, but no LP and nothing over 5000ft make the 100 useless here. The mountain climate is ideal for hydronic heat and this boiler is not available. It makes no sense to me.

joel_19

ummmm

Scott it will modulate all day long by simply wiring a tekmar to it we have installed probably half a dozen that way. No need to directly control the burner. Actually a a Vito 2oo does not control the burner either it simply tries to run to whatever set point it is given. No need for any mixing unless you want multiple temperatures. We have also done the Triangle Tube and they modulate the same way. Who's Modcon allows you to directly control firing rate as in modulation of the burner from an outside source?? I've never seen 1.

Rodney Summers

vito 100

Joel

Again I fail to see how a tekmar 256 that is designed for odr of a bang/bang boiler can properly control a modulating boiler.

Is not one of the setup requirements of the 256 to adjust the boilers limit to the max for design DD and so when any temp less than design modulation will cut off abruply

I agree fully with Scott this is not a good control method

scott markle_2

terminals 17 and 18

Joel, Terminals 17 and 18 on the low voltage terminal block of the TT are for 0-10v external modulation, This is not a hack it's standard stuff. I believe that condensing boilers that don't provide outboard modulation control are the minority, aside from the vito 200 I'm not aware of a mod-con that doesn't. Since the TT comes with odr this interface is not essential to maximizing condensing operation. If a more sophisticated combination indoor/outdoor feedback system or multi boiler control is desired this connection provides options beyond the basic ODR that comes with the boiler.

But the vito-100 which provides no such packaged ODR is not being used to it's best potential if operated by the on/off control you describe. Sure the boiler may be modulating but if the set-point is 40 degrees above what is actually required it's hardly doing this with the sort of intelligence that it should be. If the dial on the boiler is set at 160 and your 256 wants 120 your going to end up with the burner over throttling to reach 160 and the Tekmar cycling the boiler on and off to provide the 120, Hardly an efficient application. Maybe I'm missing something.

Anyone using this boiler should really look into the Open Therm protocol.

scott markle_2

0-10v

Contacts 17 and 18 on the TT are for 0-10v modulation control. Aside from the Vito 200 I'm not aware of a mod-con that does not provide this. Do your home work. This is an important interface if more sophisticated control options than those provided with the boiler are desired or for multi boiler controls etc.

Since the Vito-100 has no built-in ODR the importance of an 0-10v interface is even greater. The set-point dial provided would be fine for snow melt or an air handler or other fixed temp. applications but is woefully inadequate for applications that benefit from variable temperature. Maybe I'm missing something but I don't think your serving your clients very well with that 256 pairing. The nice looking x-block job also has shortcomings in that the boiler is likely operating at higher than required temperatures for much of the heating season. Still this has to much be smother than a low mass modulating boiler being run with a bing/bang ODR.

If I was doing a Vito100 I would be looking seriously at Opentherm thermostats. I can bet that the OT to 0-10 module is not cheep and then you would still need a modulating boiler control. For a nice panel rad job Why not find a source for one of these Opentherm Tstats? See pdf.

joel_19

t stat

That is an interesting stat that I had not seen before.

I agree that the Vito 100 has limited capabilities. However that depends on what you are asking it to do. We are using that boiler as a replacement unit in traditional baseboard systems. The boiler gives them a modulating burner which is the key much more important than wether it condenses or not. In most apps there is sufficent baseboard to keep it condensing a good chunk of the winter anyways.

Every other contractor selling against us is selling atmospheric vented in the chimney. So No i do not think we are doing our customers any disservice at all. While more sophisticated controlls could eek out a few more % the added cost and complexity could force many of these folks back to non-modulating in the chimney boilers.

If doing a new radiant system from scratch or panel rads we would be using a Vito 200 anyhow.

ALH_4

8-24

The first question I had when I saw the Vitodens 100 was why would anyone buy the 8-24 over the 8-30? The 8-30 would obviously provide better DHW production and still modulates down to 8kW. The price is a little lower on the 8-24, but if they only offered one model, maybe the price on the 8-30 could be a little lower.

Just something I have wondered but never asked.

Gordo2

vitodens 100 or 200

We are building a 23 unit apartment building. Each unit will have it's own domestic hot water and radiant heat system. They will range in size from 700 sf up to 2300 sf. For this purpose stepping up to the initial cost of the 200 gets expensive. Is the additional components for the 100 going to make this cost compatible?

ALH_4

Vitodens and Apartments

If space is at a premium, the Vitodens 200 6-24C combi might be a nice option, depending on DHW demand. The labor savings with the 6-24C may make up some of the cost difference from the Vitodens 100 and an indirect. Verify that water quality will not be an issue with the Combi DHW heat exchanger.

Mike T., Swampeast MO

Since even the basic Vitodens 100 literature plainly states that it's designed for non-Viessmann controls to include reset, I thought your problem was with the method. It seemed that you wanted direct control of burner modulation; not indirect control of modulation via a supply target.

Had that .pdf on my desktop ready to post when I saw that you'd posted. Will admit it took a bit of searching to find out how you connect a Vitodens 100 to a reset controller.

As long as you can set the 0-10V output of the Tekmar controller you want to use for target temperature output as specified by that .pdf you shouldn't have any problems.

Some suggestions:

1) If you're using a fancy Tekmar with supply temp sensor, I believe such should be located on the emitter (secondary) side of the LLH. Never, ever forget that anytime secondary flow exceeds primary that the supply temp in the LLH (that available to the emitters) will be lower than the primary temperature! If the Tekmar engineers have done anything approaching what I think, the controller will learn when and how much to adjust the target away from the reset curve to maintain the desired supply temp to the emitters.

2) I know for a fact that Viessmann engineers consider frequent adjustment of the modulation rate--especially in the Vitodens 200--to be inefficient. I believe this is highly related to the design of the INOX radial HX which fortunately is shared with the Vitodens 100.

3) Note that the input module [appears] to be a replacement for the thermostat input! Make certain you use that half-dead band in the 0-10V protocol to prevent the boiler from attempting to maintain target when there is little or no load on the system! At minimum input the 8-24 model will consume about 4,550 btu during 10 minutes of firing. Since it uses a hot surface ignition system instead of the more robust and expensive direct spark, the Vitodens 100 surely isn't designed to operate in "pulse" or "batch" mode where it fires for only a few seconds. During periods of low load, higher than normal deviation from room temperature setpoint(s) may well be required to ensure reasonable firing times. The input module and modulation logic in the boiler itself may take care of much (or all) of this for you, but I can find no mention in the literature.

4) Be aware that since it lacks the boiler-controlled variable-speed primary circulator of the 200 series, that it's essentially impossible for the 100 to constantly maintain a state of "energy out = energy required" in a multi-zone system. As I understand the operation of the more advanced "learning" Tekmar control systems, they can approximate such both by watching response in zones and making appropriate adjustments to the reset target. The goal of this is to keep as many zones calling for as long as possible without unacceptable room temperature fluctuation. The inherent load-matching ability of the 200 is, I believe, the major contributor in its ability to maintain lab measured efficiency--never forget that such is essentially "steady-state" even with modulating boilers--in the real world virtually irregardless of outdoor or indoor conditions.

5) As at least one other person said, don't think that you can turn a 100 into a 200 with the "appropriate" third-party controls. Without the variable-speed primary circulator it won't ever happen and to my knowledge no control system made (other than the Viessmann Comfortrol) is capable of this--and even then such only works with the Vitodens 200.

6) If you're spending thousands on third-party control systems and want to get the most from a Vitodens, you really might want to re-evaluate. Why not use the 200 and better yet, why not use the 200 in the "German way" with TRVs and/or FHVs? Better yet you can get the full Vitodens experience by not only using TRVs/FHVs, but carefully designing the piping such that the one variable-speed circulator is the ONLY circulator in the system. (Essentially unmolested gravity systems are generally perfect for such as they have effectively zero head loss in the piping.)

p.s. Contrary to what many believe, the Vitodens 200 can be used with third-party control systems, but such requires very expensive Viessmann communications accessories. You do NOT however get direct access to burner modulation--just like with the 100, you can only vary the target temp and let the boiler itself take care of the modulation.

Mike T., Swampeast MO

It [appears] that the only "proper" way to add third-party reset to the Vitodens 100 is via an appropriate 0-10V signal that provides the reset target temperature to the boiler.

While I might be interpreting incorrectly, it also appears that once you add this ability to the 100, that the boiler's thermostat connections are disabled. In other words, the reset controller itself will provide a call for heat via the 0-10V signal. It would further appear that proper setting of the controller to incorporate the "half-dead" band in the control signal will be critical for the most efficient operation.

I have no idea what would happen if you attempt to reset the boiler via and end switch connected to the thermostat connections. Ask Viessmann!

Mike T., Swampeast MO

While it's a bit buried in the literature, the Vitodens 100 has an adjustment for maximum allowable input that ideally is set to the heat requirement of the system at design conditions. Note that heat requirement IS NOT the same as your best heat loss calculation that includes the ability to RAISE space temperature.

scott markle_3

Kevin,I agree,not compatable as far as I'm concerned. Joal, As far as keeping costs down I undersand the importance but if we are not getting condensation we may not be so far ahead of the atmospheric competition anyway. Who said modulation was more important than condensation? I think the prime benifit of modulation is keeping firing rates at a level that permits condensation. Again I would be looking at Opentherm tstats. please post if anyone gains any experience with this