Lever Pressure Gauge Oil Refill ?

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#1: Post by LewBK »

By accident, the stopper on my pressure gauge popped out for my manual lever, Rossa, and the mineral oil drained out of it. I bought mineral oil and refilled it, but how do you know if you've put in the right amount? I still see a small air bubble in it and am wondering if I need to fill it until the bubble disappears.

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#2: Post by Nunas »

A small air bubble does not matter, and gauges often come with an air bubble. As for refilling, most gauges do not come filled with mineral oil anymore. Usually, they are filled with glycerine or silicone oil. If your gauge was truly empty, then you can fill it with whatever oil clear oil you wish, including mineral oil. I've even used baby oil in a pinch. However, if it still contained some oil, then you should fill with your oil of choice, give it some mild shaking, then drain and refill. This is necessary because, eventually, oils of two different viscosities will separate. BTW, if your gauge eventually no longer reads zero, you can simply remove and reinstall the rubber plug; if the gauge isn't damaged, it will return to zero. BTW2, the oil isn't truly necessary in an espresso machine, as its main function is to dampen needle vibration, which we don't get much of with the kind of pumps in our machines. Oil does, however, lubricate the mechanism and greatly increase its longevity.

LewBK (original poster)
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#3: Post by LewBK (original poster) »

Thanks. I meant to say Glycerine, not mineral oil. But I hadn't thought of emptying it again to avoid mixing the oils.

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#4: Post by Beanz »

I have had the stopper come out on my Rossa when drying it and had to top it up a couple of times. I have always used Glycerine from the pharmacy, If you Google the manufacturer DuraChoice (assuming Ross still uses them) you will see they use Glycerine "• Liquid Filling: Glycerin oil-filled to enhance reliability and integrity. Helps dampen the effect of vibration and pulsation. Lubricates the movement, and extends the life of the gauge."
Use an eye dropper or small syringe to refill the gauge. With a little (or a lot of patience) you can move the gauge around to amalgamate the smaller air bubbles, once you get a decent size bubble turn the gauge over and remove the plug and move it around until the bubble comes to the opening and releases, then top up the level until no more space is available. You cannot overfill. You may need to do this several times to clear all the bubbles.

LewBK (original poster)
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#5: Post by LewBK (original poster) »

Thanks, Beanz. Excellent additional insights.

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#6: Post by Davi-L »

The last liquid filled gauge I installed on my machine shop air compressor (Same pressures as espresso) had a note stating to nip the top off the rubber plug at top. I suspect to prevent the gauge from being too pressurized from heat and such. Increased accuracy. They are really atmospheric devices at their bellows guts end. There are very few cases where they are needed for vibration/pulsation.