YELLOW JACKET Tech Tip: Cleaning Your Vacuum Gauge Sensor

[YELLOW JACKET]

One of the most common problems with all vacuum gauges is oil contamination. Learn how to clean the oil from you vacuum gauge and vacuum gauge sensor.

[duncan8881]

So I've cleaned my sensor with denatured ethanol from a pharmacy cause that was what was available and connect directly to 2 different pumps w fresh oil I can just barely pull 500 microns when I valve off at the gauge I get rapidly rising microns to about 5000 at best ATM at worst when I use a 6in hose it rises slower I have re sealed the pipe thread fitting in the gauge numerous times and changed the gaskets in all the fittings I'm using a 69080 gauge it seems like the gauge has a internal leak ?is this possible? Or both of my pumps are shot I have a bullet and a cfm super evac suggestions ?

Sent from my Nexus 7 using Tapatalk

[garychance]

So I've cleaned my sensor with denatured ethanol from a pharmacy cause that was what was available and connect directly to 2 different pumps w fresh oil I can just barely pull 500 microns when I valve off at the gauge I get rapidly rising microns to about 5000 at best ATM at worst when I use a 6in hose it rises slower I have re sealed the pipe thread fitting in the gauge numerous times and changed the gaskets in all the fittings I'm using a 69080 gauge it seems like the gauge has a internal leak ?is this possible? Or both of my pumps are shot I have a bullet and a cfm super evac suggestions ?

Sent from my Nexus 7 using Tapatalk

Is this your only gauge? meaning can you compare it to another? The hose could also be suspect.

[duncan8881]

I've ordered another gauge but I'm pretty remote it takes a while to get here 2weeks approx . when I hook it direct to the pump I barely pull 500 no hose at all . pump is supposed to pull 25m

Sent from my Nexus 7 using Tapatalk

[garychance]

I've ordered another gauge but I'm pretty remote it takes a while to get here 2weeks approx . when I hook it direct to the pump I barely pull 500 no hose at all . pump is supposed to pull 25m

Sent from my Nexus 7 using Tapatalk

so exact results, both pumps, and same gauge with no hose?

[duncan8881]

Cleaned the sensor with permatex brake clean reassembled and it all behaves the same except its on line further down on the gauge .pulls down to 250 rises rapidly yo 3000 at best when I valve off at the gauge if I valve off with a bit of hose it rises a bit slower

Sent from my Nexus 7 using Tapatalk

[duncan8881]

Pretty sure the permatex leaves a little residue

Sent from my Nexus 7 using Tapatalk

[duncan8881]

Yes same results :\

Sent from my Nexus 7 using Tapatalk

[duncan8881]

If I wasn't in the middle of something I'd send it all to the factory to get tested

Sent from my Nexus 7 using Tapatalk

[garychance]

same results 2 pumps, return it for warranty. (Don't blame the pumps)

[duncan8881]

Ugg. Thank you garychance

Sent from my Nexus 7 using Tapatalk

[garychance]

If you cleaned as suggested, and hooked direct to pump. its actually good news, as its probably under warranty, and pumps cost quite a bit more then the gauge. (If you have a buddy with a gauge double check with it)

[YELLOW JACKET]

First, if not testing against another gauge, you can't be 100% sure that all the oil is out of the vacuum gauge. The 69080's do not leak, so it either still has oil, or the pumps are going bad. It appears there is still oil in the vacuum gauge, especially if both pumps are not pulling below 500.

Please see our quick tip video on "Why Microns Rise." It could be there is no leak in the gauge nor is the pump bad, but what you're seeing is caused by moisture molecules releasing from the system, pump, or gauge. When you isolate a vacuum gauge, this should be done in 1/4 turn increments instead of just closing off completely. This allows the molecules to release from isolation valve and ball valve, and then will pull again. The other options is to open then close, open then close, and repeat this a few times. What you will do in either situation is to watch for the rate of rise. It should creep up slower and slower and eventually level off and not rise any more.

[duncan8881]

OK I didn't crack it a quarter turn . I'll try that next

Sent from my Nexus 7 using Tapatalk

[dodge]

I have a different problem,the gauge pull down to below 50 microns very quickly,less then 10 minutes, I tried cleaning it same result,brought another gauge same condition. These are on system change outs,not pulling vacuum on compressor or condenser coils just line set and evap coil
It also slowly rises to above 500 microns after 10 minutes I am using a JB pump 5cfm any thoughts, the system perform well after they a re started any thoughts on this just seems to fast, I generally run my pump for a 1/2 hour to 45 minutes

[YELLOW JACKET]

You are right to question this. It should take a while to get a lineset and evaporator down to 50 microns, especially if there are hoses involved as well.

If you are using a 69086 vacuum gauge, make sure you have the correct sensor number entered into the handheld unit.

[dodge]

I will check it again but I'm almost positive that I entered the correct number, remember that I replace the original one for the same concern. Aside from having two micron guages attached at the same time how else can I determine if I have a faulty one.
If I were to hook up my vacuum pump to an empty recovering cylinder is there a spec on how long it should take to get to below 75 microns, remembering that I am only concerned with too short a time, if it took longer than I would suspect a weak pump/ bad guage manifold or hoses