I have an older Slant Fin Liberty oil furnace that safeties out sometime around 4 hours. It seems to be intermittent because I have seen it do more than one cycle. The recent history on it is about a month ago I changed the electrodes, nozzle and filter. It was running fine until a couple of days ago. I noticed pressing the reset caused it to kick right back on and appear to run normally for several hours. What should I look for to troubleshoot this? We did get oil delivered. Maybe something with the fuel?
UPDATE 1:
I noticed this morning when I reset it, it fired then quit. I could hear the electrodes zapping. I had to reset it an addtional time after it quit. I'll pull the filter and check the flow later this morning.
UPDATE 2:
Added a video to demonstrate what I am dealing with. Please watch.
Best Answer
I wanted to share the additional steps I took to troubleshoot the issue and describe what was ultimately causing the issue. The problem comes down to a weak and short spark. I was able to test the spark and witness that it was very quick and dim. I replaced the transformer and the protector relay. I likely did not have to replace the protector relay but figured it could not hurt. A retest with the new components showed a strong spark. Now I am back in business and should not have to worry about either of those components for years to come.