EcoRenovator - View Single Post - Homemade u-tube manometer

abogart · 02-07-12, 06:10 PM

I have recently found that a water tube manometer is actually a very simple instrument. Basically, a measured amount of water is suspended in a u-shaped tube. One of ends of the tube is used for pressure measurements, the other can be left open to the atmosphere to measure static pressure, or can be attached to the low end of a pressure system to measure differential pressure. There is a scale behind the tubes for making measurements.

There are two basic types of water tube manometers, vertical and inclined. Since I plan to measure the external static pressure of my duct system and air handler, I chose to start with an inclined manometer because they can read much more precisely in a small range (0 - 1" H2O in this case).

I built this one from a length of clear 5/16" vinyl tubing, which cost me $2.90 for 10 feet at the hardware store. The base plate is just a piece of 1/4" plywood that I had laying around, cut to 8" x 12". The tubing is held to the base plate with zip ties. I measured at 1" intervals up from the bottom and made lines across for the scale.

Here is the semi-finished manometer held against my cold air return.

It's not nearly professional-looking, but it should serve its purpose. I have yet to get some food coloring for the water and fill it to the proper level. Once I do that I'll tape it to the return and run the scaled end of the tubing into the return, and the other end to the supply just above furnace.

02-07-12, 06:10 PM	#1
abogart Efficiency Afficionado Join Date: Jan 2012 Location: Michigan, US Posts: 68 Thanks: 21 Thanked 6 Times in 4 Posts	Homemade inclined manometer I have recently found that a water tube manometer is actually a very simple instrument. Basically, a measured amount of water is suspended in a u-shaped tube. One of ends of the tube is used for pressure measurements, the other can be left open to the atmosphere to measure static pressure, or can be attached to the low end of a pressure system to measure differential pressure. There is a scale behind the tubes for making measurements. There are two basic types of water tube manometers, vertical and inclined. Since I plan to measure the external static pressure of my duct system and air handler, I chose to start with an inclined manometer because they can read much more precisely in a small range (0 - 1" H2O in this case). I built this one from a length of clear 5/16" vinyl tubing, which cost me $2.90 for 10 feet at the hardware store. The base plate is just a piece of 1/4" plywood that I had laying around, cut to 8" x 12". The tubing is held to the base plate with zip ties. I measured at 1" intervals up from the bottom and made lines across for the scale. Here is the semi-finished manometer held against my cold air return. It's not nearly professional-looking, but it should serve its purpose. I have yet to get some food coloring for the water and fill it to the proper level. Once I do that I'll tape it to the return and run the scaled end of the tubing into the return, and the other end to the supply just above furnace. Last edited by abogart; 02-08-12 at 11:02 AM.. Reason: Changed title to "inclined manometer," as this is no longer a u-tube design.