Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit

ECR (Dunkirk) question,

I have a customer with a Q90-100 grossly oversized <em>non- modulating</em> condensing boiler.

Its input is 100K, the building H/L is only 39K.

As the firing rate is fixed through the burner orifice plate, gas-valve orifice and blower air-baffle, I should be able to downfire this to the 50 model by changing these right.

Has anyone tried this? ;-)

PS- And yes, I will set it up with my Bacharach.


  • Al Letellier_21
    Al Letellier_21 Member Posts: 402
    modifying gas boiler

    Don't even think of modifying the boiler unless it is an approved option by the you know the term "adopting liabililty'??? And get it in writing before you leap !!!
  • Al

    This boiler is only made in 3 sizes,, everything is identical between the 3 except orifice sizes.

    You sound alot like Tim,, negative, what`s the deal? 
  • Slimpickins
    Slimpickins Member Posts: 323
    I wouldn't unless....

    You would have to change the differential pressure switch in addition to the orifice plate and air baffle.  I've seen the Q's over condensate if they're underfired, water will fill the pressure switch tubes.

    It seems like you could, the heat exchanger and inducers are the same for all models but I'm with Al on this, if it's not in the installation manual or you can't get a letter from the manufacturer, I wouldn't do it. Too many lawyers out there.

    How about selling them a buffer tank and add reset controls to the tank? That would be a good upgrade to the customer.
  • Al Letellier_21
    Al Letellier_21 Member Posts: 402
    negative ?????

    Not even close Dave.....but I do forensic work for the insurance companies and expert witness stuff for the lawyers and I truly understand the word liability.... too many guys in our industry think they can just change things around to make it easy on themselves when a simple phone call to the rep or tech support will tell them if they can modify equipment in the field. You should  do a little research into what goes into getting a piece of equipment certified, tested and approved for public will open your eyes. In ten years working with the insurance people, I have sadly seen several contractors lose their businesses and one guy lost everything he had because he modified a piece of equipment and was under insured...he wasn't covered for stupidity. I don't mean to be blunt but it may be the only way one of you out there gets the message.

    Dave, you must care about what you do as you took the time to ask the please listen carefully to the answers and heed them....we are just trying to save you and your customers a world of hurt.
  • I will not argue with you,

    as I have too much respect in you for that.

    But let me ask you this,,, "IF" this boiler was oil-fired and approved for different nozzles, does that mean the "factory supplied" nozzle must be left in?

    Take a look at the O/I manual for this unit,, everything(I forgot to mention the proving switch before), is the same except the factory items as that way they don`t have to manufacture 3 models,, only the minor "interchangeable" parts.

    Also look on the "specs" for burner replacement,, same thing. ;-)
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 15,425
    How about

    asking ECR where they stand as far as the warranty goes if you do this, Dave? That way, you're covered. 
    Retired and loving it.
  • Thanks Dan,

    I WILL do that.

    This unit was installed(not by me) in 2003, and has not been yearly serviced anyway as she was told it didn`t need-it. So I would think any warranty is gone.

    The original installer simply oversized to "cover his butt",, but I just want help reduce her fuel bills with the present equipment. ;-)
  • Tim McElwain
    Tim McElwain Member Posts: 4,480
    Dave there is not a negative

    bone in my body, it is just that I like Al have seen trades people who were trying to "simply help someone out" lose everything because they did not follow protocol on adjustments or retrofit. When you see bodies carried out of buildings from CO poisoning or have to investigate an explosion caused by some do gooder then you get very cautious.

    I have installed over 3,500 conversion burners in coal and oil furnaces and boilers. I assume full responsibility for all of them and have even picked up the warranty on those still in warranty just to insure coverage due to liability. That kind of coverage is not cheap.

    I also do expert witness work and it is a very different world in the court room than it is in the equipment room believe me. I have seen some very tough and wonderful tradesmen brought to tears by some aggressive lawyer who just ate them alive on the stand.
This discussion has been closed.