low water cut off not shutting down boiler

Moshe

hello gentleman



I have an old american standard oil fired steam boiler. last week the boiler ran low on water and melted the controls.(thank G-d that we were home and smelled the plastic burning smell)

I replaced the controls and transformer. I found the problem with the water feed and corrected it. i fixed the leek (the gasket on the water coil was worn away and was dripping) I am stuck though on the following Why is the boiler still firing when the water feed is on? I double checked all the wiring and it looks correct.



Is it possible that the wiring in the lwco (67 series with a honeywell pressure guage on top) is not working but the wire to the water feed is?



I am thinking of just adding a secondary lwco that will just block out the boiler. Does that make sense?

Jamie Hall

You are one

very fortunate puppy.



How often, if ever, has that low water cutoff and feeder been blown down?  The first thing that strikes me is that the mechanism may be able to drop far enough to activate the automatic feeder now that you've fixed it, but not far enough to trip the low water cut off switch.  The only reliable way to check that is to open the blowdown valve on the LWCO while the burner is firing.  That will drop the water level in the the LWCO (but not that fast in the boiler) and the burner should shut off.  In the process you will clean the goop out of the LWCO -- which should be done at least monthly, and preferably weekly anyway.



If the burner does not shut off when the blowdown on the LWCO is opened, you have a very serious safety hazard (as you've found out).  It's cold out there, but if it were mine I'd get a pro in there right now (like tomorrow morning, if possible) to trouble shoot that LWCO -- and probably find that you need to replace it.  (And I wouldn't run the boiler at all unless I were watching the water level, until that was done).



You certainly can add another LWCO at a slightly lower level, with a manual  reset lockout on it; most larger boilers have that anyway.