Viessmann Vitodens 200

Mike Norgan

We have one Installed on this little project.

Paul Cooke

Viessmann Vitodens 200

Does anyone know if this unit is available yet.

Does anyone have one up and running?

Paul Pollets

It's Available

at the local Viessmann rep.

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Steve Ebels

Vitodens

A truly awesome piece of equipment in every respect. Yes, we have installed them and we have a lot more quoted right now. Silent operation, modulating burner, Variable speed pump on some sizes, extremely efficient. What else would you like to know?

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ralst

DHW

Anyone have opinions on the DHW capabilities of this unit. I am interested in it but system designer tells me that could not keep up with what I would consider normal hot water demand ie shower and washing machine at same time. Any thoughts? Thanks Bob

Paul Pollets

DHW

You will need to install an indirect tank with the Vitodens-from 42g to 120g are available.

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Steve Eayrs

I've got Veissman questions too..............

I have a Vitodens 6-24C unit on order, that I plan on using as a direct on-demand dhw, and radiant floor heat system. ( I realize the dhw output is low, but just have to see what it can do)
Plan on using the low-loss header they recommend, but could anyone tell me if I could possily use it as the mixing point for the radiant system? Its a small system. I noticed that the low-loss header has a aquastat and wiring hooked to it. Can't imagine that this is to protect this boiler from cold returns. Doubt they would be a problem with this unit. Could this aquastat possibly be used for a lower temp. mixdown point?
Anyone installed one like this?

thanks, Steve

Steve Eayrs

I should mention that...

I usually use Tekmar injection pump controls for radiant, and am also familliar with Veissman controls, but just trying to see if I can save some $$$$, for small system, and couldn't help wondering why this wouldn't work.
thanks, Steve

heatboy

The low loss header........

isn't a mixing device. Think of it as Viessmann's version of P/S. The only thing it does, is allow for the correct flow rate through the boiler in high flow, low Delta T heating systems. Due to the Comfortrol type control on the Vitodens, any other control line is not needed. A 3-way mixing valve and actuator is all that is needed for your radiant. Even if you could add a tekmar control, why mess it up? VSI on a condensing boiler does nothing but decrease the efficiency of the boiler by increasing return water temperatures and decreasing condensate.

Warm Regards,

heatboy

"Expert in Silent Warmth"™

610.250.9885

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Paul Cooke

Thanks

My supplier up in Portland is going to hold a half day class with the Viessmann rep covering installation, service, troubleshooting and programming. I didn't know these were available yet. Sounds good.

Looks like competition for the Munchkin.

kf_2

Injection w/condensing boilers.

An injenction pump is typically used to protect the boiler loop from low water return temps. The last thing you want to do with a condensing boiler is raise the return water temps. the lower the better.

kf

tcutler

Vitoden

If you had a small radiant system wih one temp you could use a three way without the actuator and set it manually.Then set the curve on the boiler to your desired temp. The three way will protect the floor from any high temps. As far as the domestic. If your load is over 3 Gpm I feel you will have a problem keeping up.

Steve Eayrs

condensating boilers/ injection pumps...

Thanks for the responces....But I should clear up my questions some. When I said I usually use injection pumps on radiant, I did not say I was planning on using it here.
But that also brings up another question... I understand the lower the return temp. the better on such boilers, but whats the difference if you use a 3-way or an injection pump mixing system? Would not both raise the boiler return temp.? I would imagine the low-loss manifold also raises the boiler return some too? I understand the intent of the manifold is similar to a P/S piped system, and primarily for flow rates/head pressure, etc., but would it not somewhat mix down the radiant temp. side of things? How much?
Does anyone have any information (or a web site) that could tell me what the stat on the low-loss manifold does?

thanks for your insights,
Steve

heatboy

I don't want this...........

to be a Viessmann seminar(g). A three way mixing valve is the best option for Viessmann's condensing boilers or the Vitola. It allows direct return water back to the heat exchanger with no supply water with it as opposed to a 4 way or VSI. The sensor that is used with the low loss header monitors the common supply temperature going out to the system. Since the boiler is essentially uncoupled, the sensor gives a true temperature reading of the system. It will then control the modulation of the burner to blend the right amount of boiler water to raise or lower the temperature going out to the system. For a radiant only system with a mixing valve, it maintains a supply water temperature of 12° - 15° warmer than the radiant needs. The mixing valve and sensor are required to attain precise mixed temperatures. While you could run a radiant sytem without the mixing valve, it's not a good idea since precise water temps won't be available without it. Sure, if it is radiant where precise control is not needed, i.e., commercial slab where finite control is not needed, etc., go for it. In residential applications, always use the mixing valve.

Warm Regards,

heatboy

"Expert in Silent Warmth"™

610.250.9885

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GW

I have fresh in-mind schooling

The Vitodens is a low mass boiler- it really doesn't need a 3-way, unless you plan on running a high temp circuit. The internal variable speed pump (two smaller boilers) steps up and down in 10 rpm increments, just like a motor-mixer will modulate up and down.

The header is simply to keep the boiler water from hurting the boiler in a high-flow system (the boiler is not a super-highway like its bigger brothers... things are a little tighter in there). If you're below the rated flow rate, you don't even need the header. If your deltaT is stretched out, (you do the math... I don't have the Viessmann book in front of me) you could even run the Vitodens at full BTU with out the header. If you plan on using the traditional 20* deltaT, you'll need it at full BTU needs.

Basically, if you don't want to play with the system curve and the pump curves, simply buy the header and be done with it.

Gary

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Steve Eayrs

Thanks much Gary

for the answers. That was the info I was looking for. I was at the Veissmann school in Canada a few years ago, but they did not have the Vitodens then.

thanks,
Steve

heatboy

Another benefit...........

...to using the low loss header is, it creates a settlement zone for system debris. Since the boiler's HX is relatively small, it has no place for debris to accumulate like all the other Viessmann boilers have. For the minimal upfront cost of the header and the advantages of having it, I don't consider it an option and will include it on every project.

Warm Regards,

heatboy

"Expert in Silent Warmth"™

610.250.9885

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