OP
Fl_Key_Guy
Registered
Everyone has been great with offering suggestions on why my output nitrox is not matching the input!
I have been calibrating by shutting off the oxygen flow and calibrating to 20.9 on the stick with the compressor running. I reduce initial humidity by positioning the air intake at the outlet of a window air conditioner. For sure it's wet ambient air in the Keys. For sure it is dry air in the tank. As far as humidity goes, I have not noticed much difference between readings if calibrating to 20.9 in the open air and then testing a known straight air fill- both are 20.9, maybe a tad higher off the air fill but never a whole percent. ( I was actually checking for LOW oxygen on tanks not used in a while.)
I'm filling banks as well as tanks, and filling 4 tanks at a time when on direct tank filling, so the little bit of unenriched air in the compressor and hose would not affect the percentage noticeably. The compressor runs for hours.
There is very minimal restriction in the stick- much less than any scuba regulator that isn't free flowing. I have a manometer coming to confirm vacuum level under running conditions.
Although the hose between the stick and the intake filter seems secure enough at both ends, I'm going to add hose clamps in case I am getting some leakage due to vibration.
If nobody else has had this problem, it MUST be air sneaking in SOMEWHERE. I'll also check the air tightness of the intake filter housing.
But not tomorrow- it's DIVE DAY! Gotta breathe up some of that weak nitrox....
I have been calibrating by shutting off the oxygen flow and calibrating to 20.9 on the stick with the compressor running. I reduce initial humidity by positioning the air intake at the outlet of a window air conditioner. For sure it's wet ambient air in the Keys. For sure it is dry air in the tank. As far as humidity goes, I have not noticed much difference between readings if calibrating to 20.9 in the open air and then testing a known straight air fill- both are 20.9, maybe a tad higher off the air fill but never a whole percent. ( I was actually checking for LOW oxygen on tanks not used in a while.)
I'm filling banks as well as tanks, and filling 4 tanks at a time when on direct tank filling, so the little bit of unenriched air in the compressor and hose would not affect the percentage noticeably. The compressor runs for hours.
There is very minimal restriction in the stick- much less than any scuba regulator that isn't free flowing. I have a manometer coming to confirm vacuum level under running conditions.
Although the hose between the stick and the intake filter seems secure enough at both ends, I'm going to add hose clamps in case I am getting some leakage due to vibration.
If nobody else has had this problem, it MUST be air sneaking in SOMEWHERE. I'll also check the air tightness of the intake filter housing.
But not tomorrow- it's DIVE DAY! Gotta breathe up some of that weak nitrox....