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Display Troubleshooting

SpareTimer Member Posts: 2
I have a Weil McLain 97+ 110 gas boiler that has been working well for the past couple years after we installed it. This morning I got a call from my wife that we lost heat. It was windy out and I figured that may have tripped an auto shut-off if it pushed against the exhaust too much. I would get home from work and just have to reset it.

Returning from work I checked that the exhaust/ intake was clear and made my way to the basement. No breakers were tripped but the display was completely blank and void of any colors (vs red/purple/blue/ other warning colors with the display). I flipped the on/off switch to try to reset the boiler without effect. I verified the wire directly connected to the boiler was in fact live. I turned off the power to the boiler, removed the cover and traced all the lines making sure they were all connected (including unplugging and plugging them in). Yet again when everything was replaced and power was turned on, the display remained completely blank and the boiler pretended it was not receiving any power source. I again turned off the power supply and proceeded to remove the main display to check the fuses (low voltage 3 amp fast-blow and line voltage 12-amp slow-blow) which both seemed to be in fine shape visually. I checked all the connections again and reattached the main display with the same disappointing results.

I admittedly do not have a multimeter to test the fuses and am hoping they still may be the problem despite looking fine. Beyond that I can't imagine the display somehow going bad within a few years.

I've been racking my brain on anything else I can troubleshoot but haven't been able to come up with anything else. Just looking for anything I may have missed.


  • rick in Alaska
    rick in Alaska Member Posts: 1,396
    Sounds like you have covered all the basic troubleshooting steps, except using a meter to verify. I believe you have a fried board and will have to replace it. Could it have been subject to a power issue such as a brownout, or some kind of surge?
    HVACNUT Member Posts: 4,856
    Is this an Ultra boiler? There is a 120v, 12A glass fuse in the control module. Still need to find out why it failed.
  • SpareTimer
    SpareTimer Member Posts: 2
    I finally have the chance to dive into this today...

    No brownouts around here, I can't rule out a power surge but all other electronics in the house are fine so it would seem unlikely.
    It is not an ultra.

    I've got to pick up some fuses and will get in contact with WM anyway. Crossing my fingers a simple fuse will do it for now despite (1) they look fine and (2) not knowing what would have blown it. But if I get heat back for now that's a question down the line.