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

Lochinvar Armor Sputtering On Startup

Rizz861 Member Posts: 52
Just as the title says. Boiler is only a year or two old, it just got cleaned, gas psi was checked, and combustion test performed. Flame current is good (12.4mA) with new ignitor and flame sensor. I even called lochinvar to go over the issue and they had me tweak the low fire settings with no success. It is a member/leader setup and both boilers do it. They come on at 48% and sputter, but once they’re running they sound just fine. When I get into service mode and mess around with firing percentage, nothing causes this. I can start from low fire and go all the way to 100% and no issues. It only occurs when starting up. Lochinvar tech support was stumped and so am I. My guru at the supply house mentioned sagging pipes. That had me think about the install. I remember they tried to use a-bands on centrotherm pipe and the inspector nailed them and made them switch to those split rings with the rubbers. Getting split rings right with a pitched pipe and a ceiling that isn’t perfect can be a bear of a task. I’m wondering when they swapped the hangers they may have made some flat spots or spots that are pitched the wrong way. Have you guys seen sagging/bad pitched vents cause sputtering on any of your boilers you work on during startup only? This is the only thing that makes sense to me as I’ve checked all the boxes on usual suspects. 


  • Alan (California Radiant) Forbes
    Check the condensate for clogging and backing up into the heat exchanger. Make sure there's an air gap between the boiler drain and pipe.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • Rizz861
    Rizz861 Member Posts: 52
     Check the condensate for clogging and backing up into the heat exchanger. Make sure there's an air gap between the boiler drain and pipe.”

    It’s definitely not that as I serviced this myself. I believe it is the venting from what I’m hearing so I’m gonna check the pitch the next time I get out there. I will also take exhaust piping off to see if it does that noise. 
  • dko
    dko Member Posts: 611
    edited June 2023
    What are a-bands?
    Swivel loop hangers?
  • Derheatmeister
    Derheatmeister Member Posts: 1,549
    What size Boiler?
    What is your altitute?
    2" or 3" Exhaust Vent and how Long ?
    Propane or Nat Gas?
    Did you Clean the HX ?
    Can you post the combustion results?
    Did you clean the Venturi brass orifices?