Test Pressure Measurement Accuracy - Why it's important

[larrycavan]

I don't know how many other guys have seen this but I see it all the time on my FP1 equipped bench.

When testing a port, I always take readings at "exactly" the test pressure I'm using [generally 28"]. I regularly see a variance of a "up to" a couple of CFM come and go with as little as a tenth of an inch of test pressure.

Now that' something that may be easily missed with a regular water guage, especially if it's positioned such that seeing the scale at eye level [where it relates to your test pressure] is concerned.

Another thing I've seen is that just as with a water guage, if there's a turbulence issue, it's hard to hold the exact test pressure with the FP1 [that's a positive thing]. Now the effects of that are also dependent upon the size of the flow control valve in your bench to some degree but still, it's good to see the sensativity of the instrument.

[gofaster]

This is where electronics are nice. My motor controller keeps my test pressure within -.0.02" or less of my set test pressure, and never over. Adjusting manually I can not even see that small of a difference on my manometer.

No wonder so many of the forum members don't even bother with manometers!