Central Boiler 5648 stopped working, then came back to life - fuse?

[Keltydog]

Hi All -

New member, here, long time lurker.  I've owned and operated a Central Boiler CL 5648 for 15 years with no problem. A few days ago when I went to load the stove, I noticed the damper was shut even though the temp was below 175 degrees. I assumed it was a solenoid issue and I had purchased one a few years ago in anticipation of this. I installed the new solenoid, but that didn't fix it.  

The owners manual and other sources suggested looking at the fuse.  My CL 5648 had only one fuse at the control panel and it was labeled "light/controller fuse" - it was fine.  Numerous mentions on this board and other Central Boiler sources referenced a "solenoid fuse" - but after an hour of inspecting every panel on my boiler, I was unable to find a solenoid fuse.  There was no fuse near the solenoid when I took off the cover even though I saw pictures of that arrangement on other Central Boiler OWBs.

A day later I discovered that the new solenoid has come back to life and the damper door was open and working.

What happened?  Has this ever happened to anyone else?  And why don't I have a solenoid fuse like other models?  Bought my OWB in 2004.  

[lxskllr]

My house furnace has an automatic damper, and it was giving me problems a few years ago. Turned out it was funked up, and a squirt of wd40 fixed it. Perhaps you have an intermittent problem due to crud in the works.

[E Yoder]

Does CB use some kind of high limit that trips if the stove overheats? On the HM's I work with if it trips a snap disc at 190, it resets at 150.