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ALARM Honeywell RM7800 L 1012 Fault 110

I have a Fault code 110 on my Honeywell controller. I have checked the jumpers and they are in the same state that they are programmed to be in. I can't seem to figure out what has caused this problem all of the sudden. Does anyone have any insight on what to look for while troubleshooting a fault 110.
The model is RM7800 L 1012 this is on a modualting firetube boiler.


  • Steamhead
    Steamhead Member Posts: 17,000
    Here's the manual:


    From the looks of it, you may need to replace the control. If you do this, it's best to also replace the purge timer, flame detector amplifier and anything else that plugs into the 7800.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • ScottSecor
    ScottSecor Member Posts: 864
    I agree with Steamhead. Might be able to re-use the display tool if there is already on in place.
    EBEBRATT-Ed Member Posts: 15,829
    They have made several display modules. Some have less functions than others. We had some of these controls that were powered and with all limits and safeties calling would not start the burner. Had to buy the new display module which showed more faults than the older display module. Turns out the controls we had had lost "their post purge time" Once we programmed the post purge time the burner ran.

    These controls can be sensitive to electrical noise.

    You can't call Honeywell. The best you can do is the local Honeywell rep.

    Chances are the chassis could be bad. The purge timer is just a card that seldom goes bad and the old amplifier could be fine.

    You may need the "enhanced version display module" if you have an old one