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Thread: New DO meter user with questions!

  1. #16
    Join Date
    Jul 2008
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    UK
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    The Milwaukee result is credible, maybe slightly high but depends on temperature. If your meter always read around 27ppm on tap water even before you calibrated it, then there certainly sounds to be a problem.

    Just to confirm, you are regulating the gas flow rate before the meter and flowing this through with no restriction at the outlet side?

  2. #17
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    Sep 2012
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    Moorhead, Minnesota
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    Yes, we are using the flowmeter to throttle down flow before the DO meter. The only restriction would be the slight restriction of the ~4 feet of tubing connected to the out on the meter. The tubing was supplied by the manufacturer. The meter reads our compressed air at 8-9 ppm after calibration, which is what i would expect. But the 27ppm coming out of the tap and samples from our fermenters pre-pitch is really throwing me for a loop.
    Last edited by Junkyard; 01-14-2018 at 12:56 PM.

  3. #18
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    Oct 2013
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    Dallas, Bangalore and soon Goa
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    I was half joking about having the air compressor next to a de-gassing tank, I wouldn't think this would be a likely issue in 99% of cases.

    At this point, in your shoes, I would feel confident in thinking the Beverly is not functioning properly. As TL said, the Milwaukee reading seem realistic. You have gone through calibration as carefully as possible, and frankly if it requires more than that, the instrument becomes more cumbersome than it should be.

    I would say your last option before abandoning the Bev would be to ask for Hamilton to ship you another new unit and return the faulty one for their in house testing purposes. If they aren't willing to do that, then I would ask for a refund (and opt for the Pentair/Haffmans, Orbisphere or other). As I have said before, I find these units have typically worked well for me, but I have not had the issues you are experiencing. Good customer service would swap the unit to keep you happy with their product.

  4. #19
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    Sep 2012
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    Quote Originally Posted by UnFermentable View Post
    I was half joking about having the air compressor next to a de-gassing tank, I wouldn't think this would be a likely issue in 99% of cases.

    At this point, in your shoes, I would feel confident in thinking the Beverly is not functioning properly. As TL said, the Milwaukee reading seem realistic. You have gone through calibration as carefully as possible, and frankly if it requires more than that, the instrument becomes more cumbersome than it should be.

    I would say your last option before abandoning the Bev would be to ask for Hamilton to ship you another new unit and return the faulty one for their in house testing purposes. If they aren't willing to do that, then I would ask for a refund (and opt for the Pentair/Haffmans, Orbisphere or other). As I have said before, I find these units have typically worked well for me, but I have not had the issues you are experiencing. Good customer service would swap the unit to keep you happy with their product.
    The rep is asking me to recalibrate the low end with 99.999% research grade n2. Says thats why we are experiencing these issues. He says they have never had an end user with a problem with any of their units to date.

    What you said about cumbersome functionality really nails it on the head for me. Its a portable DO meter that cost $7k this thing better be pretty damn functional.

  5. #20
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    Oct 2013
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    Dallas, Bangalore and soon Goa
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    If you can find the "zero" gas N2 at a reasonable price in a small cylinder, then I would give it a shot, but I HIGHLY doubt this is going to make any difference. My guess is a faulty unit/sensor and I would ask first if they will take it back and calibrate it in house since you are having such issues. Again, good customer service would take care of your concerns.

    I would push saying I want a refund if they don't accept that as a reasonable option. They will probably take it, see the issue, replace it and tell you it worked fine all along, but at least then you will have an operational unit. You could also ask them if they are willing to refund your dollars for both the unit and the gas if the pure N2 calibration doesn't make a difference.

    Also, tell everyone who you are dealing with if they don't fix the issue so that they feel a little peer pressure to do the right thing. Gusmer Enterprises? or are you dealing with Hamilton directly?

  6. #21
    Join Date
    Jul 2008
    Location
    UK
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    Before going to the time/cost of sourcing grade 5 N2, just run some good-quality CO2 or N2 through it to see what it reads on a low-O2 medium. I seem to recall you got low results from it and it's the high end that's just way too high?

    The only way I can see that using high-purity zero gas will help is if your current supply is massively high in O2. It would depend on the calibration protocol internally - ie. how the unit realigns the response graph - as to whether this would make the difference or not.

  7. #22
    Join Date
    Dec 2017
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    Red Lodge Montana USA
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    Quote Originally Posted by Junkyard View Post
    We are using grade 2 co2 99.9% to calibrate currently. We then measured a dry Hopped IPA at 0 PPB. And measured tap water alongside an inexpensive milwaukee membrane DO meter (the milwaukee read 13.5 ppm, the beverly read 26 ppm.

    We then went back to the same co2 source we calibrated with and it measured 26 ppb. (Is this an acceptable error range?)
    Do i ask the manufacturer to take it back?
    I think that the gas does make a difference. If you are using 5-9 gas, you are much more likely to hit the low end. You are essentially trying to calibrate a zero point with possibility of <100ppb O2 in the gas. The number of nines after the decimal place are very important for purity. It's more expensive, but more accurate.

    At 99.9% gas is not certified to a 0.01% purity, which equals 100ppm. There could be UP TO 100ppm of another gas in there, making your calibration real whacky. See this from Merck: http://www.merckvetmanual.com/append...pb-conversions

    Hope this helps! Cheers - Madeline

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