MoFlo pressure issues

Julie Nelson jnelson at
Wed Oct 15 09:47:32 EDT 2008

Hi y'all,

First some equipment info - I have the SmartSampler, the standard pressure console and
the JunAir compressor. When I press run or hit the button on my SmartSampler, the
pressure drops about 2 psi before slowly building back up to the set point.  When I press
the boost, it takes about 20 seconds for the boost to slowly rise to it's set point -
sometimes longer.  Needless to say, I have a sore thumb and it takes about 2 minutes for
a sample to start flowing.  Some things I have done that make it better are:  I bleed
about 10 ml of water out of the top of the JunAir every week (I bleed it out every other
day and get about 2-3 ml each time).  I open the top of the pressure console and bleed
water out of those regulators as well - not as much and it is random as to which hose the
water comes from, but I do usually get water from both the sample and the pressure
regulator.  The bottle on the side of my JunAir is not full, nor do I let it get full. 
Yes, it is humid here in the South!
, but my MoFlo is 7 years old and the problem has just started this year (and we are in a

My main question is - how do I isolate the problem?  My suspicion is the JunAir
compressor has lost it's ability to remove water from it's machinery. I've got the JunAir
troubleshooting guide and have checked its filters - which seem to be working fine.  We
do not have a service contract so replacing parts just to see what fixes the problem is
not an option.

I'm living with the problem now, but have a fear that one day, it just won't flow. 
Thanks in advance for any advice you can offer -


Laboratory Manager
Flow Cytometry Facility
Center for Tropical and Emerging Global Diseases
University of Georgia

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