Your surge tank needs to be filled with air. There is a schraeder valve in the top of the tank that will allow you to hook a tire pump to it. Fill it with enough air to stop the hammering.
show a decrease in pressure due to air leaking into the system.
The gauge should be electrical.
A pressure gauge indicates actual pressure and a differential pressure gauge indicates the difference in pressure.
THE NORMAL GAUGE PRESSURE SHOULD STAY AROUND 12 TO 19 P.S.I
Pressure gauges work based on the principle that a fluid or gas exerts a force on the gauge's sensing element, which then deflects or moves in response to the pressure. This deflection is converted into a reading that indicates the pressure being measured. The gauge is calibrated to provide an accurate and precise measurement of the pressure exerted on the sensing element.
A compound gauge is a pressure gauge that displays both negative and positive gauge pressure measurements. Gauge pressure is a measurement of pressure relative to ambient pressure. For example, if ambient pressure was 14.7 PSI and you were to measure absolute vaccum using a compound gauge, the gauge would indicate -14.7 PSI.
The very first thing you should see is the oil pressure gauge start to indicate pressure. (This is assuming you have an oil pressure gauge, but all large trucks have them.) If you don't have any pressure within five seconds, turn the engine off.
Bourdon's tube pressure gauge cannot be used to measure negative pressure. This is because absolute pressure must be measured and the Bourdon gauge only indicates the gauge pressure.
Gauge pressure usually refers to the pressure difference between ambient, atmospheric pressure and the pressure in a vessel or line. A gauge pressure of zero would mean that the vessel or line was at atmospheric pressure. Normally the pressures of interest are ABOVE atmospheric so the gauge pressure is positive. Vacuum gauge pressure measures how far BELOW atmospheric pressure a vessel or line is. As such vacuum gauge pressure may be measured as a negative number - or for convenience it may be reported as a positive number with the caveat that it is "vacuum gauge pressure", meaning that the reported pressure is how far atmospheric pressure is above the pressure in the vessel or line.
A pressure gauge is called a gauge because it typically measures pressure relative to atmospheric pressure, which is often considered as the reference point or zero point for pressure measurements. On the other hand, a meter usually measures absolute values without reference to a specific point.
A pressure gauge measures pressure in a system relative to atmospheric pressure, displaying the reading in units such as psi or bar. A manometer measures pressure by balancing the weight of a liquid with the pressure being measured, often displaying pressure differentials in terms of inches or millimeters of the liquid column. In summary, a pressure gauge gives absolute pressure readings, while a manometer measures pressure differentials.
These are corrugated to increase the sensitivity of the pressure gauge.