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Post by Guessed on Jan 24, 2024 14:24:24 GMT
Anyone else notice?
Why is it that when I replace a deaer pump in august, my dac =192 to achieve -24inhg. 5 months later the machine is pulled for failing negative pressure test. When I check my deaeration pressure, its like -15inhg and I have to increase my dac to 207 to achieve -24inhg. i could tell the pump was running low when machine was pulled. Brushes are fine, just replaced a year ago.
This is not the only machine with new pumps that have to be calibrated within 4 to 5 months of installation. Do new pumps not hold pressure like before?
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pacnw
Full Member
Posts: 187
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Post by pacnw on Jan 24, 2024 14:52:35 GMT
I find what you are stating very common.
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Post by thor on Jan 24, 2024 15:07:03 GMT
Yes seen this as well, Ive always thought its the new pump head wearing (breaking in). Normally after the first re-adjustment after replacing, do not see the issue again
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Icebonez
Junior Member
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Posts: 55 
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Post by Icebonez on Jan 24, 2024 15:50:42 GMT
Normally after the first re-adjustment after replacing, do not see the issue again I replaced more than a few of mine last year. Most of those pump heads required one adjustment a few months after the replacement, and they hold steady after that. My guess is they have a "break-in period" as mentioned before. "Is it a bug or a feature?" The answer is Yes. |
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Post by Guessed on Jan 24, 2024 16:14:46 GMT
Thanks, that makes sense since I do see quite a few of these. Maybe because I haven't replaced hardly any deaer pumps in the past 5 years, I forget about new pump syndrome.
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eric
Full Member
Posts: 111
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Post by eric on Jan 24, 2024 17:16:10 GMT
Thank you for sharing. Putting this in my back pocket knowledge bank.
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stuff
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Post by stuff on Jan 24, 2024 18:33:56 GMT
so where is all the material going from the wearing of those gears during "break in"?
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Post by guestJan on Jan 24, 2024 19:48:57 GMT
There are no materials going anywhere from the pumpheads. It's all magnets. We need a magnet expert to explain/breakdown what happens when they energize over time. My guess-pertise(lol) it's magnetism probably increases(maybe decreases abit ) and stabilizes after some time. Over longer period of time, magnetism decreases so DAC goes up.
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phillipashleyludlow
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Post by phillipashleyludlow on Jan 24, 2024 22:23:07 GMT
There are no materials going anywhere from the pumpheads. It's all magnets. We need a magnet expert to explain/breakdown what happens when they energize over time. My guess-pertise(lol) it's magnetism probably increases(maybe decreases abit ) and stabilizes after some time. Over longer period of time, magnetism decreases so DAC goes up. I think what your describing are called eddy currents under Lenz’s law of electromagnetism. I also think that as the Teflon wears after manufacturing, it breaks itself in, and may need adjustment due to smoothing of surface area on the Teflon ring. with the loss of contact on the commutator from friction with the brushes, coupled with this supposed break in of the gear head creates an loss in equilibrium that has to be adjusted or accounted for after said period of break in. tl:dr= its a mechanical part that has to be adjusted periodically to ensure proper function, as is with any mechanical part. |
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