Pressure rising past pressuretrol setting

John MacGregor

Hello,

I have a 1 pipe steam system and even though the pressuretrol (subtractive...i think) is set to cut in at .5PSI and the dial is set to 1.5PSI, the pressure is rising beyond that.

Originally, the problem was that the boiler was short cycleing, allowing the pressure to get to 5PSI, then cutting the power, only to have it fire again when the pressure read 3PSI. I had the pigtail cleaned of thick black sludge and sediment but now, even though the pressure gauge is still climbing to 5PSI, it waits until the pressure gauge is at .5PSI before refiring.

I can't figure out what would be wrong with the pressuretrol to make it think that the pressure is only 2PSI when the gauge is reading higher than that. Assuming that my pressure gauge is correct, what do you think?

Thanks! Jenny
PS. My landlord is clueless and reluctant to call in a professional, but seems to take the suggestions I give him (from this board) really well!

Mark K

It's probably your pressure Gauge

Hi,

I have the same problem with my boiler. My tech told me that the pressure gauge was broken, because it's mounted directly on the boiler, and the heat fried it. He told me that he sees that all the time. My gauge consistently reads 5psi while the boiler is running, although the pressuretrol is set to cut out at 1.5psi.

Dean_7

pressuretrol and gauge

See the thread "Question for steamhead or mad dog"

John MacGregor

Thanks for the help!

This system looks pretty cobbled together and has lots of issues but I'm glad to know that its probably the gauge and not the pressuretrol...

Dale

pressuretrol

If you have a mercury switch type is is level with the pigtail 90 degrees to the face, if it is an old pa404a they arent all that accurate. I would try a new gauge but wouldn't be surprised if the 404 is off scale. You may be able to adjust the differential down to see if it will cut out at 2psi. If not time for a new one.