Pressuretrol craziness; can I add a second pressure gauge?

SethK

I woke up on the coldest morning of the year and immediately noticed my boiler had been running for much longer than usual and lots of valves and vents in the house were hissing. I figured it was because of the -8 degree weather and some had hissed before, so I repacked 3 or 4 valves, replaced a vent, but things still didn't seem right. Then I noticed the boiler pressure was way to high and it was still firing. I forget the exact pressure, I just turned it off fast and got away from it. After some online research I removed the pigtail and unclogged it with a wire and hot water and cleaned it out; the boiler seems much happier now.

But... with the subtractive pressuretrol set around 1.8 PSI minus 0.5 PSI it was still firing when the internal siphon gauge read 3 PSI. I've never really paid attention to the pressure gauge before so I don't know if this is a new behavior. I slowly turned the pressuretrol down past the end of the scale before the boiler shut off at 3 PSI.



It has been operating normally at that setting for 2 days, but that can't be right, can it?

Is my gauge bad? The pigtail? The pressuretrol? Can I put a T under the pressuretrol and attach a Home Depot pressure gauge to see what pressure the pressuretrol is seeing, or will the steam destroy the gauge? I'm not sure how to diagnose what's wrong.

Thank you!

Fred

It is possible that Pressuretrol has failed or needs to be recalibrated. It is also possible the tiny hole in the bottom of the Pressuretrol (inside the hex nut that mounts on the pigtail is clogged. Check that. I'm not sure how to recalibrate that style Pressuretrol. Someone on here may be able to help.
You can put a Tee and and a couple short nipples with an elbow on each end , on top of that pigtail and mount a 0-3 PSI gauge next to the Pressuretrol. That way you can see what the Pressuretrol is seeing.This is the gauge many of us use:
http://www.valworx.com/product/low-pressure-gauge-25-0-3-psi