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Teledyne LAARS propane ENDURANCE boiler

Good afternoon all, I went to a call last night for a banging noise that a home owner's Teledyne LAARS propane fired direct vent boiler was making. It sounded as though it was percolating but the boiler maintained a pressure of 18 to 20 psi and reaching a max temp of 199 degrees Fahrenheit. ( or so the read out said.) The relief valve, system can vent, expansion tank, and backflow feed were replaced within the past year. I could not replicate the issue while on site and according to the H.O. it is an intermittent issue. I monitored the operation while all 4 heating zones were operating as well as operating only one zone only and the boiler had seemed to function as it is supposed to. I am no expert with this brand of boiler and was only able to apply what basic hydronic heat knowledge I have and no air seems to be in the system and no over pressuring issues were apparent. I am looking for some input to see if I am missing anything and/or input from others that are more familiar with this type of system. I have also attached a few photos of the boiler as well as a video of the sound it was making shortly after I left for my next call.
Thank you in adavance,
David M. Jr.



  • Banging noises are usually an indication of water flashing to steam when there's not enough flow through the heat exchanger to pick up all the heat being generated.

    Check the amp draw of the pump to make sure it's within spec's. Check the wiring connections at the pump as well.
    Often wrong, never in doubt.
  • Le John
    Le John Member Posts: 208
    Sounds like it could also be from late ignition. I have one that would ignite late every now and which would rumble the closet it it was in. Changed the igniter and did did a combustion analysis. Unit was out of range. One the adjustment was made that issue went away.