Manufacturing steam boiler.

JStar

I'm getting into light commercial service for the first time. I have some questions.



I had a late call at a manufacturing lab with a Peerless LC-12 Steam Boiler.that was going down intermittently. After asking the usual questions, it turns out that the maintenance crew's idea of maintenance is to blow down the low water cut-off once a month, and reset the controls when it stops working. So, it looked like the problem was plugged up pigtails. I wrote up my estimate and haven't heard about it since.



So now my questions...



The boiler had three pressure controls. Is this for safety? How do you determine where to set them? The lab used steam to clean copper kettles. The pressure controls were set for 8, 10, and 12.



Are there any exceptions to the accepted header piping? This boiler was piped so that the steam main was on the opposite end of the header as the drip / equalizer, with the supply risers from the boiler in the middle. I know it's not the way it should be, but if there aren't any (noticeable) problems, is it a concern?



For a lab like this, where they use the steam all day, is the boiler just being controlled to maintain pressure? Is anything else telling it to shut down if it's not being used? Are there timers for these, when the building shuts down, does the boiler automatically shut down. Does somebody manually shut the boiler off at the end of each shift?



What do you recommend for routine maintenance in a lab like this?

nicholas bonham-carter

peerless process steam

those several pressure controls were probably for a "mod-u-pack" burner staging system, which is probably not needed in this application.

i would find out the pressure requirements for the process using the steam, and perhaps restrict it to low fire for economy.

maintenance should be more frequent because of the constant addition of fresh water, introducing more solids into the boiler [hence the clogged pigtail]. blowing down the boiler drain should be once a month minimum, with perhaps removing the plug in the mud leg area for inspection, and cleaning.

as far as piping goes, if the steam is as dry as they need, with no noise, then i suppose dumn luck has protected them.

it does seem a waste to keep the boiler on when it is not needed;  especially as it can steam from cold in 20-30 min.--nbc