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Micron gauge woes

webbch on Sun August 29, 2010 1:12 AM User is offlineView users profile

I've had my Robinair 14777 micron gauge for about 2 years now, and it sees very intermittent use (can go over 6 months between usage). Anyway, it's already leaking. I dead-ended it on the vacuum pump, and while it easily pulls down to 40 microns, once I close the valve on the pump, it drifts up to about 1500 microns in about a minute, 2000 microns if I wait a couple minutes. This makes it almost useless to me for evaluating if the system is holding vacuum. (I spent a day chasing a system vacuum leak only to find that it was the darn gauge)

I've tried cleaning the sensor using rubbing alcohol, per the manufacturer recommendations. I tried putting nylog on the o-ring it has, and that also did nothing. I even tried installing an additional in-line shutoff valve to verify that the vacuum pump shutoff valve wasn't the source of the leak. Each of these test yield the same drift characteristics. Anybody run into this before?

I ordered a CPS VG-200 as a replacement, but it'd be nice to get the Robinair working properly. My next thought is to replace the o-ring on the gauge. However, the "o-ring" is more like a small "tube" and clearly unique to this unit. Anyone know where you can get replacement parts for this? Thus far, my search results have come up with a replacement sensor unit as the only available replacement part for this unit (for $80). Or is this just a "throwaway" item?


Edited: Sun August 29, 2010 at 1:42 AM by webbch

bohica2xo on Sun August 29, 2010 3:05 AM User is offline

Call Robinair Customer Service:


They should be able to get you a new seal.


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

webbch on Fri September 03, 2010 2:37 AM User is offlineView users profile


Turns out it wasn't the micron gauge that was leaking.....instead, it was 6 out of my 7 charging hoses that can't hold a vacuum after sitting mostly unused for about 3 years. I started pulling a vacuum on the low and high sides of my manifold gauges individually, and ran across a single one (on the high side) that would hold a vacuum down to 500 microns. So I moved that hose to the low side port, and it still held a vacuum. I then performed the same test on all of my other hoses, and none of the other hoses would hold a vacuum down to less than 1500 microns.

I guess that I should disconnect the hoses from the gauge set during storage. Hopefully a rebuild kit will put it back in order. Does anyone put copper lines on their manifold to avoid this kind of issue?

iceman2555 on Fri September 03, 2010 9:44 AM User is offlineView users profile

Don't beat yourself over the head....overlooked seals on service hoses and actually sealing rings in R&R machines are a most over looked aspect of equipment service.
Cannot help but believe that a great majority of labor time is wasted searching for leaks in a system when the 'leak' was in the service equipment.
Never did the copper line thing, but simply service my manifolds regularly.

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

webbch on Fri September 03, 2010 9:03 PM User is offlineView users profile

By "service my manifolds regularly", do you change the seals like once a year, flush them out periodically, and keep them disconnected (so the seals aren't always compressed) when not in use?

I'm just hoping that replacing the gaskets and maybe flushing them out will let me pull the hoses down below 300 microns to remove them as a concern item. Thanks!

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