Yes, it is necessary to cut or pinch the filling plug of the pressure gauges; since the gauges are airtight, there can be a pressure difference between the inside of the pressure gauge and the atmospheric pressure, distorting the pressure gauge reading.
By cutting or pinching the plug, both pressures are compensated, ensuring that the reading of the instrument is correct.
This phenomenon is especially noticeable in low pressure ranges, between zero and 1.6 bar, as well as in vacuum gauges.
The maker is assuming that you will permanently mount the gage in an up right position. The little tip is to let the oil expand and contract. To use it as a portable gage then leave the tip on it. I have one with a garden hose female end on it. I use it to check my water pump pressure. It is thirty-five years old and still has the little tip.
Been using gauges like that for the same purpose for years and have never vented one. Piece of advice as long as you can find the ones like you've got now keep getting them. The ones made with the little lever valve on the top to vent them tend to leak wether they are opened to the vent position or not....BTDT.
I just got a new liquid filled pressure gauge that has a little rubber vent on the top of it. It says once it's installed I'm suppose to cut the tip off. First off, this gauge isn't going to be permanently installed, I'm just using it to test pressure on small motors. Second, I was playing with the part that I'm suppose to cut and it started to leak fluid. So do I need to cut that vent? Seems like if I do it's going to leak all the fluid out. I've never had a fluid filled gauge before and I don't recall ever needing to cut a vent. Oh, and it's a PCI 4702 0-30 PSI gauge from Surplus Center. Thanks, K
Copyright © 1997-2024 Yesterday's Tractor Co.
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy