secondary low water cut off on residential steam boiler

wo47

Where is the best location for a secondary LWCO with manual reset on a gravity residential steam boiler, the house was converted into a business and a state inspector came in to inspect as commercial, he said my customer must add one. The minimum water line is just below the bottom of the site glass? It is a Bryant  BS2 steam boiler? Thanks

 

Steamhead

That's a re-branded Dunkirk Plymouth boiler

and I don't believe a secondary LWCO tapping is provided.



The actual probe for the primary LWCO is mounted in the front of the boiler, and a cable connects it to the LWCO control which is mounted on the side of the boiler. It might be possible to attach a Hydrolevel manifold to the sight glass at a higher level, install a primary LWCO there and change the original LWCO, which would now be the lower of the two, to the secondary one. But I've never done it that way on that boiler...........

wo47

Secondary LWCO

Thanks for the info Steamhead, the inspectors write up stated that the secondary LWCO had to be above the boiler manufactures lowest permissible water level, the boiler has a sticker about 2 inches below the low point of the sight glass with a horizontal line showing that point as the lowest permissable water level.

I ended up removing the sight glass so I could install (2) 1/2 x 3/4 tees, one at the top and one at the bottom of the sight glass connections, I installed 2 so when I put my sight glass back on it would be the same distance from the boiler on the top and bottom of the sight glass (keeping the glass straight when reinstalled), I then plugged the top tee and installed my McDonnell & Miller 751P-MT-120 LWCO into the branch of the lower tee, then I reinstalled the sight glass and wired my LWCO to shut the burner down if the water level ever gets that low. I should pass inspection as I am lower than the primary LWCO but higher than the lowest permissible level, I'll let you know what the inspector says, Thanks again, Walt