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Viessmann Combustion Analysis

obg8
obg8 Member Posts: 22
in Gas Heating
So I did my combustion analysis on my personal Viessmann install at my house results are not exactly where I want them.. Spoke to Viessmann and there are no adjustments to be made to the boiler itself..

Model - Vitodens 100-w B1HA

Combustion
o2 - 7.6-8%
co2 - 8.8-9.1%
co - 50-60ppm
EA - ~55

The system is two pipe vented, I would like to see the co2 about 1-1.5% higher, any suggestions?

LP Gas
Inlet pressure 13in

Comments

  • lchmb
    lchmb Member Posts: 2,997
    inlet pressure is 13" flow or lockup?
  • obg8
    obg8 Member Posts: 22
    static inlet pressure is 13 running pressure is around 12.5
  • lchmb
    lchmb Member Posts: 2,997
    edited November 2017
    If this is the only appliance on the regulator I would drop it to 11 on flow.... If your lockup is only .5 above flow, your line's are sized properly and you have an excellent regulator, usually see more of a difference in lock up..
  • obg8
    obg8 Member Posts: 22
    I have adjusted it from 11-13 to see how/if it affects combustion, it really doesn't do much. i realize if i lower my o2 my co2 will increase but i'm not sure how to do that besides covering my air intake which is ridiculous... Viessmann tech support doesn't offer any help either.
  • obg8
    obg8 Member Posts: 22
    anyone have any suggestions?
  • newagedawn
    newagedawn Member Posts: 586
    how old is the system? after a certain age the combustion chamber and other factors wont allow for top effiency, this is due to leaks somewhere
    "The bitter taste of a poor install lasts far longer than the JOY of the lowest price"
  • GW
    GW Member Posts: 4,892
    Can’t adjust combustion????? Seriously? For real? I did a bunch of WB1B, they are adjustable. This newer model isn’t?
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • Tim McElwain
    Tim McElwain Member Posts: 4,644
    There should be a throttle adjustment screw on the gas valve to allow for some minor adjustments. What does the I and O manual call for in the case of LP for combustion readings? I do not have my manual handy or I would look it up.
  • j a_2
    j a_2 Member Posts: 1,801
    Just checking , did you install the conversion kit or did it come as l p...recheck dip switches and such....the boiler should be dead on from the factory,as far as combustion results go
  • GW
    GW Member Posts: 4,892
    edited November 2017
    i just scanned the i-o manual, no adjustments to be made.

    edit, well if it's Lp then you need the kit and set the programming for LP, I presume you did this??
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • j a_2
    j a_2 Member Posts: 1,801
    GW said:

    i just scanned the i-o manual, no adjustments to be made.

    edit, well if it's Lp then you need the kit and set the programming for LP, I presume you did this??

    Kinda what I was thinking, on the above post
  • NYplumber
    NYplumber Member Posts: 503
    I just ran into this on a recent install. Viessmann doesnt want you to adjust the gas valve. From what I see it does look similar to gas valves installed on other mod-con boilers. There is a screw if I recall that is painted over. That would be your adjustment screw (not the offset).
    I was told that this gas valve is self adjusting. Being that there is no lamba-pro sensors, it is either doing this internally or - and I think this is it - Viessmann sets it for the center of the range and allows colder weather to bring the combustion results in one direction and warmer weather to effect it in the other direction.

    btw, what was your out door air temp?

    I will go back to the b1ha and check what my reads are for combustion. That system is using indoor crawl space air.
    :NYplumber:

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