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McWeil Lain Oil furnace issues

Jackieb Member Posts: 1

I have had issues for years with this furnace since purchasing the home. I have had many techs in and out the door, they generally replace the nozzle, the basket, the filter and clean it out and say I am good to go.  Well not really. 

This furnace shuts off at night now around3am-6am.  Have recently started having this as a issue.  About 6 months ago we had a new Aquastat put on also.  (honeywell) 

Replace the nozzle the other day and filter again because it was misfiring at the end of its cycle. 

It seemed to be running smoothly, now its doing this very short cycle at night about 30 seconds?  Then its off

This goes on a bit throughout the evening, then at wake up the house is down to 50 degrees and the furnace is off with the reset button lit.

I hit the reset and the furnace fires up and runs normal pretty much the rest of the day.  yesterday I had to do it twice.

We also cleaned the eye. 

Any help would be appreciated...I know it sounds confusing...it is


  • billtwocase
    billtwocase Member Posts: 2,385
    Do you have

    Taco 571 zone valves? It could also be the cad cell relay. They can chatter, then lock out. Could be a plugged fuel line, could be many things. Was the aquastat changed for the reset problem? If so, it has nothing to do with your reset problem, unless it is a 8182. Need pics and more info, and it may be time to change service personnel.
  • lchmb
    lchmb Member Posts: 2,997

    are you located and have you tried the "find a contractor" on the top of the page?
  • Doug Hiscock
    Doug Hiscock Member Posts: 6
    W-M issue ....


    Sounds like the OB motor; dead spot in the winding,( think car starter), or faulty internal start switch. If the motor is NOT a PSC or has a Beckett label on it; replace it w/ a PSC motor. The primary control would be my 2nd suspect.
    Agway Doug
  • lchmb
    lchmb Member Posts: 2,997

    rather than guessing get someone in to do a proper diagnostic on the unit. Guessing what may or may not be wrong may cost you a lot of money...
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