Stop ignoring steam drum level indicators on startup

I swear I've seen three guys this month try to skip the pre-check on those Honeywell transmitters before firing up. Got called to a site last week where someone cooked a 50-ton boiler because they assumed the sight glass was accurate. Has anyone else caught a rookie making this mistake lately?

2 comments

2 Comments

simonp401mo ago

The Honeywell ST 3000 transmitters are actually pretty reliable once you get them zeroed right. But about the sight glass thing, those things can get dirty or have a bubble that throws off the reading pretty easy. I worked with a guy last year who trusted the glass over the transmitter and ended up flooding a steam drum because the glass had a small air pocket. Modern transmitters are usually more accurate than a sight glass long as you calibrate them right. Always double check both before you hit the start button.

sam_rivera1mo ago

Yeah the ST 3000s are solid once you get them dialed in. But the flooding story kind of shows the real issue. The guy probably didn't notice the air pocket because he was looking at the wrong part of the glass. Sight glasses need to be blown down regularly to clear out steam or sediment, otherwise you get a false high reading if there's condensing vapor at the top. Transmitters aren't perfect either. If the impulse lines get plugged or the manifold is leaking you can get a drift that's just as dangerous. I always check both readings against each other and do a quick blowdown on the glass, then if they disagree by more than a couple percent I shut down and investigate before firing anything up.