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Viessmann help?

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Comments

  • Ted_5
    Ted_5 Member Posts: 272
    Willing to help

    Jim, I could help you with a drawing. Where are you? You could e-mail me directly if you want. I am a Viessmann rep in MN.

    Ted
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928


    Provided each loop is very close to the same length, Danfoss told me that you can serve multiples with a single FHV using "mainfolds" and reverse return. You'll have to plan carefully for air removal and such will still be somewhat of a pain, but it can be done.
  • scott markle_2
    scott markle_2 Member Posts: 611
    loads

    Jim, What do you mean by "The total load is only 48,476 Btuh/hr and the radiant load is 35,623Btuh/hr." Seem like the whole job is radiant to me.

    Also if the total load is 48,476 then based on a 20 degree delta I don't see why total flow rates would need to exceed 5 gpm.

    GPM=BTU/500x deltaT right? Your list totals out at over 9 gpm. Am I missing something? Are we over pumping for a reason?

    If you incorporate flow meters and use balancing manifolds your circulator really only needs to be sized for total flow. Frequently systems are over pumped to ensure flow to longer loops is not bypassed by shorter ones. Most balancing manifolds are never adjusted unless there is a problem. This is because most systems are designed with so much residual head. I feel this is wasteful especially in constant circulation systems were electrical costs for pumping can be meaningful.
  • scott markle_2
    scott markle_2 Member Posts: 611
    5 mix valves and LLH for 50k !

    I was hoping someone would have some input,is my math and understanding of the relationship between heat loss and flow rates correct?

    If so why no comments on the discrepancy here?

    I'm comfortable posting my opinions: A- because I give them some thought and B- because I'm fairly confident that a lot of smart people pay attention here, and will question me.

    I think it's a bit much to post zone area's and flow rates and ask for design work here. I made no attempt to assess if the areas and flow rates add up, This is realy your job Jim.

    On a more general level it seems like the total flow rates and total heat loss on this job don't add up. How could viessmann have recommended 5 mixing valves for a job under 50k. This hardly seems like the sort of European heating design that attracted me to viessman.

    Are we being pegged for spoiled Americans that will spend anything for our luxury and comfort.

    I think pushing unnecessary equipment and system complexity that contradicts the simple elegance of this boiler is more upsetting than selling to untrained homeowners or professionals.

    Am I missing something?
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