Measuring Water Pressure

[Paradiddle7]

I'm going to be installing a water pressure based sump pump backup and I need to measure my water pressure.

I got a pressure gauge with my RODI unit. It connects to the 1/4" hose.

Is this guage an accurate measure of my overall water pressure?

 

[doubleduece]

Please explain more???????????

 

[Paradiddle7]

I need to know the pressure in the supply line. Since my gauge measures the pressure once it is reduced down to a 1/4" line, is the pressure affected by the narrowing in size of the tubing, or is the pressure the same as it would be in the 3/4" supply line?

 

[One Dumm Hikk]

Smaller diameter tube with equal volume increases the pressure. Smaller diameter with equal pressure lowers the volume of water.
It goes on from there. The relationship is almost linear. If you increase/decrease one, the other will increase/decrease. There are some exceptions but not many.

 

[Paradiddle7]

That's what I thought. I'll have to get a 3/4" pressure gauge.

 

[BeanAnimal]

No, you don't need to get a different gauge. The gauge is calibrated for the opening IN the gauge, not the pipe the gauge is attached to.

In addition, you need to know what the static line pressure of your water system is. That will give you an indication of your systems ability to run the turbine pump.

 

[Paradiddle7]

What's the static line pressure? Is that where I time how long it takes to fill a 5 gallon bucket?

Are you knowledgable about these pumps? Which one is the best one to get? I want to make sure I don't get a crappy one that can leak sewage back into the clean water.

 

[BeanAnimal]

I don't have first hand experience with the pumps so I can not recomend a good brand. The static line pressure is measured with all the valves closed. I.E. the pressure on your system when no water is running. That will give you a good indication of the service pressure. That said, it can drop significantly depending on your plumbing and your water service.