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Pigtails

Dave_23
Dave_23 Member Posts: 190
in THE MAIN WALL
I'll be working on my boiler's pigtail soon. Should I leave it dry, or prime it with a little water to separate the gauges/vaporstat from the steam.

If so, how much water is recommended?
Thanks, Dave

Comments

  • Tony Conner
    Tony Conner Member Posts: 549
    Very Few...

    ... get installed with the pigtail already primed with water, even on high pressure industrial systems. I've seen a couple of really expensive industrial instruments that require the loop to be filled with water prior to starting the system up, but even on 250 and 300 PSI systems, they usually just get installed dry. The steam quickly condenses in the loop as the pressure comes up, and it fills with condensate before much pressure is on the system.

    The sole purpose of the pigtail is to keep steam temp off the internals of pressure gauges, etc. I've seen gauges installed on steam systems without pigtails, and they'll still often work for a few weeks. You can't overfill them, so if you feel more comfortable filling the pigtail with water, it won't hurt anything. Any little bit of excess water will just drain back into the boiler or steam line.
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