# Micron meter question



## tinman

Hey Guys., Been having trouble lately getting my meter to pull down.Last few jobs 1300-1700 best it will do. Did change oil on 6cfm pump recent and tested pump after.,think i had 250 microns. I do put the meter at service ports.,however i hook to those with 6ft hose back to gauges and pump. (hoses 1yr old).
I always pressure test systems with nytro.,so leaks should not be an issue.
Any thoughts would be appreciated.


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## linebacker

I'm not a tech., but have been around a long time. If you close off the line going to the pump, does it hold the vacuum? If it doesn't the problem isn't in the pump. If it holds, you either have a bad pump or not giving it time to pump down.


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## DuMass

If you’re sure it’s not leaks, then you could try cleaning the sensor in your micron gauge with isopropyl alcohol. It only takes a tiny bit of oil or moisture to contaminate the sensor so it won’t read correctly.
If that doesn’t work and you have a gauge with a replaceable sensor, then replacing it might be the next step.
If it’s one of those cheap Supco ones or something similar and cleaning the sensor doesn’t help, then it’s time for a new micron gauge.


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## tinman

Thanks guys; It is a Subco,I have been little lax at cleaning tip,thanks for reminder. And yes it does "hold" when I shut off pump. Whats is a meter you would suggest to buy? $$?


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## DuMass

There are a lot of brands to choose from these days and prices are all over the place, but I think YJ 69086 is a pretty decent unit overall. It can often be found for under $200.00, if you shop around online. 

http://www.yellowjacket.com/node/640


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## tinman

Hooked set up directly to pump.,still 1850 microns had a short double female flaired fitting in set up., Replaces it., "410 microns!" may have had a crack in flair? Thanks again for the posts!


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## myTech

Anyone have the Testo 557 with built in Micrometer?


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## Rcb2875

tinman said:


> Hey Guys., Been having trouble lately getting my meter to pull down.Last few jobs 1300-1700 best it will do. Did change oil on 6cfm pump recent and tested pump after.,think i had 250 microns. I do put the meter at service ports.,however i hook to those with 6ft hose back to gauges and pump. (hoses 1yr old).
> I always pressure test systems with nytro.,so leaks should not be an issue.
> Any thoughts would be appreciated.


Have you tried pulling down on a recovery cylinder as a controled test? I have found systems that didn't want to pull down past 700/1000 microns yet my pump would pull down a cylinder to 500 microns just fine. Possibly a combination of very small leaks in the system or moisture/refrigerant boiling off that is trapped in the oil, though that usually only decreases the vacuum over time rather than limit the initial pull.

ugh.. just noticed the post orientation is opposite from another site and didn't look at the post numbers lol


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## Rcb2875

myTech said:


> Anyone have the Testo 557 with built in Micrometer?


May be nice to have in a pinch but as with my SMAN3 I have seen small leaks at the sight glass seat on the Testo's as well. Noat a huge leak but a leak none the less.


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## Tony Pullen

not sure the model # but feildpiece has the combo manifold guages (digital) with a built in micron guage, among many other things. great set!


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## woland

Tony Pullen said:


> not sure the model # but feildpiece has the combo manifold guages (digital) with a built in micron guage, among many other things. great set!


I think it is Fieldpiece Sman 3


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