Vitola/Radiant Heat/DHW

bruce pirger

It seems the Vitola is the way to go for me (and all) radiant floors. VB2-18 model.

I have been told by the Viessmann distributor that Viessmann recommends a mixing valve when using the boiler for both radiant heat and DHW production. I assume this is to allow the boiler to operate at a higher temperature and have no worries about overheating the radiant water. Makes sense to me.....

But, is it necessary? The whole idea of the biferral Vitola is to allow for lower water temperatures. Removing the mixing altogether seems like a good thing. Is it not possible to prevent the hot water from flowing into the radiant system with priority control on the zone valves? I have no worries shutting down my heat (in slab and also staple up) for DHW production. Thermal mass of 70,000 pounds of concrete goes a long long time. With my rather thick carpet on the staple up, I probably want a higer temp anyways...the woodstove will be burning almost always....etc.

A few things I can not seem to read about on the net...at least not in English...and maybe you can clue me in or point me in the right direction:

Tiger Loop Burner Piping System (in connection with a Riello burner on the VB2-18, although I suspect it is a generic thing...?)

Any comments on the Viessmann Vitronic 200 control system? And the Divicon Mixing Station?

I really like the Viessmann biferral technology....but it and mixing just seems to be somehow self defeating...

Thanks!

eleft(retired)

Tiger loop

This will answer one question.



al

Steve Ebels

Your gut feeling

Is correct. There is no need for the mix valve that I can think of unless you need multiple water temps at the same time. Usually staple up and inslab require different temps, so that may be the reason for the mix valve. The Vitotronic 200 will control two heating circuits, do DHW priority, manage basic system programming, and more. The Divicon is a sweet injection setup that is specifically made for the two temp purpose. Viessmann's mix valve also works very well and the Divicon will control either one.
I would also recommend that you look long and hard at Viessmann's chassis burner. It's as nice an oil burner as you can get.

kf_2

Viessmann

Bruce,

You are correct. If there were no DHW there would be no need for a mixing valve. You could just set the curve on the boiler to modulate for the radiant. However, even if you have some sort of priority valve that would seperate the DHW from the heating when there is a call for domestic hot water, when the DHW was satisfied and the valve opened again you would still have hot water in the boiler. To hot water temps could ruin some finished flooring materials as well as shock a cement slab.

Another scenario; Lets say (although unlikely) that there was a problem with the Vititronic 200 control and the boiler went into overide (which raises the boiler to high limit) there would be no way to protect the floors.

The Vitotronic 200 is a great menu-driven system control that has the ability to control DHW w/timers, full diagnostics, the ability to drive a mixing valve, and much more.


hope this helps
By the way, what area are you in?

kf

Paul Pollets

Vitola

Is a great choice for a radiant boiler. I've installed many and love the chassis burner for ease of setup and efficiency. Removing the mixing valve is not a good thing. Use a 3way mixing valve to mix the radiant floor temps, or a 4way if you want precise control of the return temperature. A high temperature pump (radiators or air handler coils) will not require mixing. The Vitotronic 200 is the cat's meow for plugnplay reset. It doesn't get any better. It will do both a mixing valve, a high temp circuit and DHW.

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heatboy

Use the three way............

motorized valve. Best of both worlds. It allows low water return temps back to the boiler, raising efficiency while modulating the water temps to the floor with no fear of overheating when domestic hot water production is needed. Also, the mixing valves gives MUCH more precise water temps for your low temperature application.

With your system, the Vitotronic 300 would be the control of choice. You are going to have two temperatures for the radiant and the 300 will run two mixing valves plus boiler reset and indirect control right out of the box.

I generally add the Tiger Loop to every oil fired Vitola system. With the new double wall fuel tanks that I offer, the Tiger Loop makes life easy.

Warm Regards,

heatboy

climatecadvanced.com

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