A high-accuracy, low-cost, low-pressure steam gauge?

Chris_L

I am a homeowner with a 30-year old Burnham residential steam boiler with the standard 30 PSI pressure gauge (one pipe system).  I've been wanting to check the cut-out and cut-in pressure of the pressuretrol, but I am too cheap to buy a low-pressure gauge.



I decided to turn the gauge glass into a manometer (for temporary use) by:

1. Closing the gauge cocks

2. Removing the fitting for the brush at the bottom of the gauge and replacing it with a 1/4 inch hose barb

3.  Attaching 1/4 inch vinyl tubing to the hose barb, and running the tubing up to a bucket attached to my basement ceiling.

4.  Opening the gauge cocks and firing up the boiler



I measure the pressure in the boiler, in inches of water, as the vertical distance between the water level in the gauge glass and the water level in the tubing. 



So, have I got myself an accurate means of measuring the boiler pressure (for less than $5)?



Please note that I am not suggesting this as a permanent way of measuring the boiler pressure, and I realize the pressure is limited by the height of the ceiling (to about 60 inches of water or 2.4 psi in my case), and I know that if I exceed that pressure, hot water will come streaming out of the tubing.  But if used only while being observed, and the cut-out pressure is

Chris_L

...continued

(sorry guess my post was too long).



I was saying if you know the the pressuretrol cuts out at less than 2 psi, this gauge seems like simple way of getting accurate low pressure measurements.



Thoughts?



Thanks,



Chris

Hap_Hazzard

As a rough approximation

I assume you know that inches of water, as a unit of pressure, is defined at a standard temperature and pressure, and for most purposes that temperature is either 60° F or 0° C, depending on the unit of conversion.

Rod

Vaporstat Tester

Hi- This sounds very similar to Gerry Gill's vaporstat tester.

http://www.heatinghelp.com/forum-thread/128249/why-do-Honeywell-vaporstats-suck-so-badly

- Rod

David Nadle

There's an easier way

You can use any tap below the waterline. A drain, for example. No need to disassemble the gauge glass. Tape a yardstick behind the tubing. Also, the conversion is 27.7 inches per psi, so your 60" tops out at 2.17 psi, not 2.4.

Chris_L

Thanks.

Thanks for your responses.  I figured if this concept worked someone had already done it, but  I didn't see anything in searching prior posts.



I had thought of attaching a clear hose to the boiler drain cock, but wasn't sure whether the hose was going to take the hot water and thought it better to start small.  Now that I know the tubing works, I may move it there to use as a check when needed.



Thanks too for the correct conversion from inches of water (27.7) to psi.  I had been using the correct figure to check the cut-in and cut-out pressures, but when I posted, I mistakenly used the inches of water I was getting (24.5) when my 30 psi gauge was reading "1" (really halfway from the peg to the first mark at "2") for the conversion.



Chris