Mixing Stick Question

[pescador775]

OK, I understand the original orifice was very small; must be a 100 + psi regulator. The reasoning is good and should work fine. So, that is not the problem. Temp differences can affect cal accuracy but I doubt that is the case here. Bear in mind that the filters and coalescers must be purged before a good reading can be made at the output. That should take only a couple minutes at most. At this point, I don't know what is going on. However, one should assume that the problem is originating with the changes to the system, and that is the stik. Three or four of the steel pads will mix anything you got and not cause much resistance. If the pads don't fit tightly to the sides it may be necessary to stretch the pads a bit. The gases have to be "entrained" and I don't see it happening with a 3 inch pipe. I'm thinking that a 2.5 X 24 inch pipe should do the job.

 

[dannobee]

4% difference between pre and post is big. Like Pesky mentioned, check the filters and temperatures (unless relative humidity was close to 100%, that could throw off the readings). Also, check the inlet to the compressor for leaks. If it's sucking air that is not going through the stick, that'll explain the problem.

 

[dannobee]

I assume when you said 4% change that the pre reading is higher than the post?

If that is the case, it's likely that the compressor is getting air that is not going through the stick. Is the air filter assembly/inlet sealed up good and tight?

 

[vbcoachchris]

yes pre is higher than post. I thought it seales up tight, but I will check that out.

thanks again for all your help

Scott

 

[dannobee]

One more thing to check.

Put a hose barb near the compressor inlet to check vacuum through the stick. Use a manometer (google it if you aren't familiar with one). Just make one out of vinyl tubing and fill with colored water. There shouldn't be more than 2 inches of water through your stick. If it's more, take out some of the wiffle balls and try again.