Internal syphon gauge & pressuretrol

jim lockard

I have pasted the contents of this other message into mine (see below) because it asks the first part of what I'm curious about. The second question I have is this; I have tried setting the cut-in on the pressuretrol on my boiler down to .5 PSI, but then it won't come on at all. It will only run if I leave the cut-in set at 2 PSI (the diff. is set at 1)

I couldn't find a response to this other person's post, (maybe I'm looking in the wrong place).

Thank You for any help you can provide


Date: November 02, 2004 09:32 AM
Author: Pat P. (patp@eppsteinuhen.com)
Subject: Internal Syphon PSI


On the side of my boiler is a pressure gauge labeled "Internal Syphon". It reads out pressures between 0 PSI and 30 PSI. I have my pressuretrol set at 0.5 cut-in and 1.5 cut-out. I have a pressure release valve that's rated for 15 PSI. What exactly does the Internal Syphon gauge report on? If its the pressure in the boiler, shouldn't it trip the relief valve if the needle exceeds 15 PSI? How is it that needle can read more than the cut-in or cut-out pressure in a closed system. I am concerned that my pressure readings on the Syphon gauge are excessive.