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Weil Mclain Ultra 80 NG - Series 2 non start

jdtaylor65 Member Posts: 3
My Weil Mclain Ultra 80 NG - Series 2 boiler developed an issue after about 1 month of this heating season. A hard lockout with an E16 error code was displayed. The troubleshooting guide suggested trying to reset the unit. Multiple resets and no luck. I also checked the fuses in the controller and both were intact. Guide suggested replacing controller, so I ordered and installed a new one. Now the boiler starts to go through the start up steps, purges, blower on etc. Gets to step 2, igniter fires and flame seen through window. Goes to 3 and fizzles out. Then display shows a 6 24 and a 9 66. Since this wasn't an issue with the old controller, I'm wondering if I got a bad controller or is there another underlying problem.


  • jdtaylor65
    jdtaylor65 Member Posts: 3
    Thanks for the reply, I read through the thread and disconnected the outdoor sensor. The boiler still will not complete the firing process as described above. :s On the bright side, at least the outdoor sensor has been eliminated. :) Thanks again.
    HVACNUT Member Posts: 5,267
    edited November 2020
    Have you tried cleaning the ignition electrode?  4.5 second trial for ignition. 
  • Tom_133
    Tom_133 Member Posts: 862
    I cant remember if the E16 is the aqua stat issue. I assume you have an indirect water heater, and if so, do you have a aqustat? The control likes a 10K sensor better, if I am right about the E16 there is a kit to resolve it, I may be wrong about that
    Montpelier Vt
  • jdtaylor65
    jdtaylor65 Member Posts: 3
    Thanks for the replies. HVACNUT, I can see an initial spark and flame through the window and then it just fizzles out. I've had ignitors fail in the past and they were just dead. I'll give cleaning it a try, can't hurt. Tom_133, not using an indirect tank for DHW, but thanks for the reply.