Pool Filter Pressure Gauge Problems? (Here’s How To Fix It)



Troubleshooting swimming pool issues can be a time consuming process if you don’t know what you’re looking for. 

When water flow is low, an area that you should focus on is the pool filter pressure gauge. This dial sits on top of your pool filter, providing you with a metered readout. But what does it mean?

The gauge will help you determine how well the entire circulation system of your pool is running.

What Is A Pool Filter Pressure Gauge?

A pool filter pressure gauge measures the level of pressure that’s building up inside your pool filter, and shows a reading based on the level of water flow going back into the pool.

The gauge reads out in PSI (pounds per square inch).

A high PSI level means there is an abundance of water flow going to the pool, and low PSI means that the water flow is constricted, and most likely obstructed somewhere along the circulation chain.

The PSI level is also the determining factor which notifies you when it’s time to backwash your sand or DE filter.

What Should Your Pressure Gauge Read?

It’s not quite that simple, as there’s no normal pressure level every pressure gauge should be measured at.

This is because there’s a wide variety of filters available, and not everyone uses the same ones. The size of the filter as well as the size and strength of your pump are also variables.

Your pool’s pressure gauge may be ideal at 5-10 PSI, whereas someone else’s may be ideal in the 10-20 PSI range. However, there’s an ideal level for your specific gauge. This is the value that is present when you first use your filter, or have just cleaned it

It’s important that you remember this PSI level as a reference to compare the current output to. Some swimming pool owners will mark the gauge with a Sharpie so you’ll always know where the needle should be. 

Additionally, there are some pressure gauges that use dual needles. This allows for one needle to stay static at the ideal level, while a secondary needle notifies you of the current pressure in the filter. Anytime there is an increase of 10 PSI, it’s a good indication your filter needs to be cleaned out.

What Causes Pressure (PSI) To Rise?

There are a few potential causes of rising PSI with the most common being dirty pool water. Pollutants that accumulate in the water will eventually be caught in the filter. As the filter gets dirtier, the PSI level goes up.

Another reason it may be rising is if you’re using a hot tub, as there’s more back pressure needed to run the hot tub’s jets. Your swimming pool water level also may be too low, leading to too much air in the circulation system.

Broken internal parts in the filter or heater can also cause a rise in pressure, as can closed or partially shut return side valves. Additionally, the return jet eyeballs can make the PSI rise if they are restricting the water flow into the pool, and lime deposits inside a gas heater exchanger can also be the culprit.

How To Correct High Filter Pressure

Correcting for high pressure usually means you’ll need to clean out the cartridges or backwash your sand/DE filter. If you’ve cleaned out your cartridge filters and you notice the pressure steadily rising after a day or two, full replacement of them is recommended.

Also of note, it’s important to be extra cautious when you’re restarting the filter, as a spike in pressure can cause the filter tank to potentially explode. For this reason you should always keep an eye on the gauge during a restart, and quickly shut things down if the needle spikes over 30 PSI.

This type of situation usually points to the cause being something other than a dirty filter.

Finally, the pool pressure gauge should come with an air relief valve (or the bleeder valve) that can be used to alleviate high PSI levels. Releasing air this way can help the system bring in more water, reducing the chances of air accumulating.

What Causes Pressure (PSI) To Fall?

Issues with low PSI are due to restrictions on water flow.

Most causes can be categorized as obstructions – the pump basket could be filled with debris, there could be something stuck in the pump’s impeller, the skimmer basket could need emptying, the main drains could be obstructed by debris, or you could have closed (or partially closed) skimmer and drain valves.

Not having enough water in the pool is another reason for low PSI, as are clogged or cracked suction lines, missing eyeballs on return jets, or air being pulled into the pump intake or pump valves.

How To Correct Low Filter Pressure

Correcting for low PSI should be looked for either at the pump, or before the pump, as these are the only areas where you’ll find the problem.

Emptying the skimmer basket, pump basket, checking the pump impeller, and the drain covers will be the go-to areas for rectifying low PSI.

Of course, there could always be a more serious issue regarding a leak or damaged equipment that will need to be fixed by a professional.

Is Your Pool Pressure Gauge Dead?

As with all mechanical things, they eventually break down, and pool pressure gauges are no exception.

If you’ve explored and exhausted all avenues and your gauge is still giving off a less than ideal reading, check to make sure that it’s actually working.

You can do this easily by flicking it with your finger. If the needle bounces, it’s time for a new one. Replacing them shouldn’t be too expensive, as you can pick up a decent one for about $30 to $50. 

Consider Installing A Flow Meter

A flow meter helps you monitor the speed of water flowing through your swimming pool system, and is measured in gallons per minute. 

As pool pump technology has advanced, flow meters are becoming increasingly common on new pools. This is because you can use them with variable speed pumps to accurately control water circulation, conserving energy while extending the life of the pump itself.

Using a flow meter in conjunction with a pool pressure gauge can give you an idea of why the PSI on the gauge might be low. If the flow of water is constricted, you’ll be able to tell on the flow meter itself and you can troubleshoot accordingly. 

No Pressure!

As a pool owner, a pool filter pressure gauge is important, and something you should become familiar with along with its normal range.

If problems arise with your pool’s water flow, using the tips outlined above can save you the frustration of wondering what’s wrong with your circulation system, and help you determine the cause and subsequent solution.

Categories: Pool Care, Pool Problems