Any need to purge a line before adding a pressure guage?

[jnjpream]

I have an electric pump that I need to test to see if it puts out the pressure it needs to (yes it has a relief valve so it won't dead head). My question is, should I attempt to purge the air from the line to the gauge prior running the pump up to pressure?

I know that when working with sprinkler systems it is advised, when running air in a system, to blow it out etc, you need to run at a lower pressure because the difference in viscosity means air will leak into more places and destroy seals etc at the same pressure where fluid/water would do no damage.

Is this something I need to worry about, or should I just screw the gauge in to the pressure out port of the pump (which is above the pump btw) and let'r have it?

Thanks.
Jeff

 

[Willl]

I need to test to see if it puts out the pressure

No 'purge' necessary.

 

[J_J]

If the pump has flow back to tank, it will purge. Depends on the valve.

 

[Jerry/MT]

I have an electric pump that I need to test to see if it puts out the pressure it needs to (yes it has a relief valve so it won't dead head). My question is, should I attempt to purge the air from the line to the gauge prior running the pump up to pressure?

I know that when working with sprinkler systems it is advised, when running air in a system, to blow it out etc, you need to run at a lower pressure because the difference in viscosity means air will leak into more places and destroy seals etc at the same pressure where fluid/water would do no damage.

Is this something I need to worry about, or should I just screw the gauge in to the pressure out port of the pump (which is above the pump btw) and let'r have it?

Thanks.

Jeff

There is no reason to purge air out of the line to a pressure gauge if there's an air buble in there. The fluid pressure will just compress it to the dsame pressure as the liquid and the gauge will be accurate. The only time you have to worry about errors with air in an other wise liquid line is if you have large elevation changes in the line.