Pressure

Dave_4

If you have a hand-pump you need a gauge, otherwise how can you know?

With a tank and hose (or any means to elevate water over a given point), if you know the height you can know the pressure even without a gauge.

The fun thing about hydraulics is that the height matters, not volume even of that tube that defines the height.

Say I have a tank of even 10,000 gallons and want to pressurize it to 15 lbs. I don't know why, I just do...

All I have to do is to attach even a small pipe, say 1/2", and run it above the tank by about 35 feet (34.65 actually). The fact that this pipe is open and is that high above the tank will impose that pressure on every square inch of that tank.

The same principle allows hydraulic fluid to power cranes and lift buckets.

Ed Lentz_2

I was talking to a builder that has had a couple of large in floor radiant systems installed. We were discussing the benefits of it all and all the different ways the systems were setup. Some thing he told me kinda puzzled me tho. He had an "Engineer" design both systems, and he said he was VERY pleased with both systems and they ran great. The thing that I was astonished with was how the engineer developed the appropriate pressure for the systems. On both jobs both were infloor (concrete) radiant, also some sidewalk as well. Anyway he had a tank installed between 15 to 20 feet above the floor that provided the necessary pressurization for the system. My little system just uses a small tank with a bladder. Is using this high tank the norm and I haven't seen it? Probably since I am a lowly HO. Still very interesting. If I had half a chance I would change professions and start putting this stuff in.

Ed Lentz_2

Physics was never my strong suit! But, I have always found it intriguing. As you said it is simple and somewhat elegant. I work with computers all day. My thought was "This is to simple! there must be some more high tech way." On my own system I have an expansion tank with a bladder and I thought that was low tech, but this has that beat. Some things just work and can't be improved upon can they? Thank you for the explanation.

zeke

While the method is novel,it is an open system and if you need 15 psi you need 34 feet of height and a makeup water controller that maintains height. Not too compelling to me , not to mention potential code problems of open systems.

Ed Lentz_2

I am not sure just how he did it then, I remember him saying they had to purge the air out of the tank. That would indicate that it isn't open to the atmosphere. Maybe that engineer is just "Old School". Oh well, all this is fascinating to me.

Brad White

I figured that

the method was to temporarily pressurize the system for testing or filling before pouring and before domestic cold water was available on-site. I did not think it was a method of permanent pressurization. As Zeke pointed out, left that way it would be an open system. Not entirely a bad thing, just different. In fact if permanent, that was the way for over 100 years.