Vitodens

Paul Pollets

You're right on with the uses for this appliance. It's best to design for a condensing load, that is having at least 20-40% (or more) of the load having a ret. temp of 90 deg or less. The lower the return temps, the more efficient the Vitodens will be. If the boiler is used in a non-condensing load, ie rads or HW coils, you may want to put a little mineral oil in the floor drain, to prevent trap seal evaporation. The boiler will not be 94%-96% system efficient when used in non-condensing modes. It will still fit in tight places, though.

<A HREF="http://www.heatinghelp.com/getListed.cfm?id=104&Step=30">To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"</A>

antman

Effeciency

I here so many good things about these units that I have a couple of questions to those who are more familiar.
I have two sepearte situations that I am considering using these, Both direct vent situations, and limited space. However I've never had the pleasure of installing a condensing boiler as of yet and i'm curious about the effeciency when used with high temps. One situation will be hydro air, radiant floor, and domestic hot water. The other copper fin baseboard, radiant floor, and domestic. Do you still get high efficiency when you get high return temps? are you able to use an outdoor reset with hydro air systems or does it require a different control strategy. Any opinions would be greatly appreciated.

Ant

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

Alan(CaliforniaRadiant)Forbes

HydroAir

Return water temperatures will dictate how well the Vitodens will condense; the lower the water temperature, the more it will condense and the higher the efficiency.

I had the same dilema on a recently installed Vitodens boiler on a radiator system. It was a gravity conversion and now, with the system in use, it condenses well because the weather here in the Bay Area has only been in the high 40's, low 50's. If this system were in the mid-west or east, I'm sure it would stop condensing. And even more so with hydroair.

So, to answer your question, the Vitodens efficiency would be high for your radiant component, lower for BB and DHW and lower yet for hydroair. But I've learned that efficiency is not the only reason to install a Vitodens. These boilers have shown themselves to be incredibly reliable so I try to sell them whenever I'm able to get a direct vent flue out the sidewall or roof, which is sometimes hard to do.

Afterthought: There was some discussion about the default high limit set at 168*. For some reason, Viessmann didn't recommend changing this to a higher temperature in which case you may not want to use it for hydroair.



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

Henry_4

hydroair and a vitodens

If you are using the vitodens on a hydroair and have selected a reset slope of 1.6, with heat operating at 68`F, the system is going to increase as temperature outside decreases. My point, I have experienced a vitodens operating on a hydroair and reseting through the entire range, it condenses like crazy since the majority of the time my outdoor temp is above 20F, the system is in continuous operation unless the thermostat picks up a big solar gain and the house is comfortable, all in a package that never goes over 160F.

The house also has rfh areas, and the comfort in those areas surpasses the hydroair, but it does highlight the control features, all on line out of the Viessmann box, plug and play ready to go.

Good luck,
Henry
Vi - Midwest

Matt Connolly

Other high quality wall mount condensing unit

If you need more than 168F and want a priority dhw control without mixing and full condensing for your low temp zones, try a Monitor MZ. Check out what they have at www.mzboiler.com

Matt