Pressure gauge lower readings

[ScudBar61]

I bought this pressure gauge from TF test kits and noticed that below 5 PSI, there are only 3 of the longer indices for each PSI. So went on Amazon and different brand gauges have the same thing. Seems there all short one indices below 5 PSI. I have been running my pump at 1200 RPM which puts it below 5 PSI. Any thoughts on why they do this?

Thanks

 

[trivetman]

A gauge which goes up to 30 psi will react differently to the first 5 psi than 5psi to go from 25 to 30. Its also not likely to be very accurate at the ends of the range.

If you need to measure low pressure accuracy you can get a gauge which measures the 0-3 or 0-5 psi range. But you probably don’t need a very accurate measurement that low down so don’t worry about it.

 

[ScudBar61]

Cool. Thanks!

 

[JamesW]

In my opinion, a gauge like this would be useful for people with variable speed pumps because the system usually starts at about -2 psi (-4.072 in Hg) when off and it might only go up 2 or 3 psi when the pump is on.

For example, if the gauge is 4.62 feet above the water surface, then the pressure will be - 2 psi when the pump is off.

A combination vacuum and pressure gauge allows you to see actual differences in pressure.

You can also install one in the pump front drain hole to monitor the vacuum pressure.

 

[Newdude]

Many of us with VS pumps simply take baseline measurements at full throttle and then return there whenever the thought arises.

Checking for filter pressure for example, is real hard to see a 25% increase at 2.5 psi, but much easier at 22 psi.

 

[ScudBar61]

Many of us with VS pumps simply take baseline measurements at full throttle and then return there whenever the thought arises.

Checking for filter pressure for example, is real hard to see a 25% increase at 2.5 psi, but much easier at 22 psi.

Thats sounds like a good plan to adopt. I’ll take a baseline at a high flow rate next time I clean my filter. Thanks

 

[Newdude]

For anything else, all you need to know is the PSI is looooooooow and nothing is gonna explode.

 

[JamesW]

I’ll take a baseline at a high flow rate next time I clean my filter.

After you clean the filter, adjust the RPM until the pressure is 5 psi and then 10 psi and then 15 psi and note the speed for each.

Later, check the pressure at each speed to compare to the original pressure at that speed.

 

[ajw22]

After you clean the filter, adjust the RPM until the pressure is 5 psi and then 10 psi and then 15 psi and note the speed for each.

I do the reverse and record the clean PSI at my four common RPMS - 1700, 2400, 3000, 3400 - and write the RPMs and PSI on the filter housing with a Sharpie. Then it an easy glance for reference.

 

[Homebrewale]

Only problem I've had at low pressures is not noticing when my filter is dirty. I should have a regular routine to increase pump speed to check the pressure but I get lazy. I usually find out while in the pool when I find little flow coming out of the jets.

 

[mas985]

With a large cartridge filter, filter pressure measurements become irrelevant (unless there is a failure). I clean the cartridges once per year and pressure never rises between cleanings.