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Riello 40 Series Gas burner (G400) goes into lockout

My G400 burner goes into lockout. We typically have between 5" and 6" water column gas pressure at that time. The system has been working reliably for the past 6 years, but in the past 6 weeks has started cycling and then failing to ignite. After this, I hit the reset button and sometimes the fan comes on and after a few moments, a relay clicks which starts the gas which sometimes catches on, and other times it pulses. Eventually it shuts off again, and we start the whole cycle over again. We have had several technicians over and have gotten many guesses, including low pressure in high demand times, and an ionization probe and flame sensor. If anyone knows about this particular system, please help.


  • vaporvac
    vaporvac Member Posts: 1,520
    Check I&O manual.under Troubleshooting...


    I'm NOT a pro, but just had these same burners installed on my Slantfin Intrepids. The installer had this problem on start-up. The are many reasons this could happen which are given in the I&O manual attached here.


    See pp 11, 14 &15

    The trouble shooting guide seems explicit as to what could cause this and how to fix it. the ioniztion probe is mentioned as a source of trouble.

    You might want to see if your technicians did these things. In the end, mine changed the orifice on the firing rate. I don't know why he thought of that or why that worked, but it did. (He might have also changed something of which I'm unaware_. Just throwing it out there.
    Two-pipe Trane vaporvacuum system; 1466 edr
    Twinned, staged Slantfin TR50s piped into 4" header with Riello G400 burners; 240K lead, 200K lag Btus. Controlled by Taco Relay and Honeywell RTH6580WF
  • Tim McElwain
    Tim McElwain Member Posts: 4,628
    Have the technician

    clean the flame rod with soft clean emory cloth. Then check the microamps which should be between 2 to 10,  3 to 5 is normal. If techs do not know what microamps/flame rectification is all about then do not bother having them even come to look at the burner.

    Concerning poor gas pressure did anyone check the pressure on the inlet side of the gas valve and on the outlet side? It is possible if the weather in your area is very cold and you are on a low pressure gas system typically 6 to 10 inches W.C. coming from the street. That could be an issue for sure, check with your locally utility to see if they have any problems on your street or area.