Vitoden and Constant Flow

hvacfreak

I have a job with 2 Vitoden 200 ( the largest models I think ) serving as reheat for a wshp closed loop. The boilers are piped secondary ( injection ) to the main loop and I am being directed by a mechanical engineer to remove control of the boiler circulators from the respective boilers and have circulation through the boiler loop( s ) based on a call for operation from the BAS ( currently there is a pump controller interfaced with the boilers , factory provided ). He is doing this in order to justify his location of a sensor from the local boiler controller ( vitocontrol-s ...sensor on the secondary discharge )....I recommended a location on the main between the close space injection tees but was shot down ). I just don't want to call the factory to confirm if they ok'd this or not....I really just want to get away from this project. Anyone " in the know " see a problem with this ( at least in the short term ) ? Thanks for any response. - M

scott markle_2

I don't know much about cooling (I assume thats what the reheat is for), but I'm curious. The very Idea of heating cooled air seems crazy to me, I know that in addition to control, there is something important about humidity involved.
I can understand how it makes sense to keep an indoor space dry, less issues with condensation in walls, comfort at a warmer temp etc., but it seems to me there must be a better way to do this than burning gas to warm air we have paid to cool.

What am I missing?

Paul Pollets

LLH

Are you using a low loss header? Have you looked at the diagram for piping multiple Vitodens boilers in the installation manual? If the manufacturer doesn't approve the installation, you'll have more problems. I'd be calling Iman at the Waterloo office. He's the main guy for design using the Vitodens.

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hvacfreak

Perhaps the term " reheat " is not correct here( just the term used on the drawings for this project )...it is the " primary " heat source serving a water source heat pump loop...perhaps a clearer way to describe it.

This product has performed well ( although not as intended ) in my opinion...and is completly wrong for this application..from the controller to the integral controllers in the boilers themselves ( it is easy to see how cool these would be in a true " heating application " however ). Just to mention...the piping was reviewed by the factory ...it's just this control sequence modification is something that is being flim - flammed ( opinion ).

Reheat ( as mentioned in the previous post ) is most often used in VAV systems ( and dehumidifiction / treatment of outside air in general ). It is the ouside air requirements in commercial buildings that make for a great many things that don't make sense. And yeah , this has no bearing on the original post. Thanks for reply's.