It is important to understand how changes in filter pressure affect your pool’s efficiency and how to resolve problems when it changes significantly.
How Does Filter Pressure Work?
The pressure gauge in a filter reads water that reaches into its tube. Normal air filter pressure is determined by what the gauge reads when the filter has been installed or after it has been thoroughly cleaned and everything is in working order. Normal filter pressure typically reads 8-15 psi.
So at what point should you be concerned about your filter pressure changing? The points of concern are whether your filter pressure is 10 psi higher than normal or 5 psi lower than normal.
What Causes Low Pressure?
Low pressure means the water is not flowing, so the pump cannot suction it as it needs. Multiple things cause low pressure, such as:
- Clogs in your pump or plumbing
- Running too many additional features on your main pool pump
Signs of low pressure are:
- Weak flow from return jets
- Low flow or no flow from water features
- Sluggish pool cleaners
- Low flow warnings from salt systems and heaters.
How to Fix Low Pressure
The first step to fixing a low-pressure reading is to check the water level at the skimmer. The water level should be at least halfway up the skimmer. Anything lower than that and your skimmer will suck in air, decreasing the pressure on your filter.
Next, check the gauge for cracks or clouding in the glass, and if the needle is stuck. If the glass is cracked or cloudy, replace the pressure gauge. For the needle, see what pressure your filter reads while the pump is off, and then turn on the pump. If the filter pressure does not change after turning the pump on, your gauge needle may be stuck, and you must replace the gauge.
Then, check for clogs in your skimmer basket, pump basket, main drain, and impeller. Debris building up in any of these restricts water flow through the system, which leads to low pressure. In this instance, clean out the piece causing the problem.
For clogs further in the piping, put a line of fish tape down the drain or piping to clear the obstruction.
To find out more information on correcting low water pressure, check out our guide here: https://www.inyopools.com/blog/how-do-i-correct-low-water-pressure/
What Causes High Pressure?
High pressure is caused by:
- Dirty filters
- Air in the system
- Suction-side air leaks
- Undersized filters
- Blockages after the pump
- Closed diverter valves
How to Fix High Pressure
Cleaning
The first step to alleviating high pressure is cleaning your filter by backwashing or rinsing your cartridges. If your cartridge filter pressure only returns to normal for a short period of time after an initial clean, your filter may require a deep clean. This will look like a chemical soak, or use a cartridge cleaner to knock out that extra stuck dirt and gunk.
Checking for Air
If there is excess air in the system, you may use the air relief valve to release it. A build-up of air comes from a leak in the suction side of the pump. Essentially, when the pump gets air in it, it builds up in the top of the filter, increasing filter pressure while decreasing the flow rate of the water through the filter.
For suction-side air leaks, check the skimmer basket for bubbles or splashing. There are multiple ways to detect an air leak. All of our recommended methods work based on the air leak pulling a substance into the pump. You can find a detailed description of these methods here: https://diy.inyopools.com/article/test-suction-side-air-leaks/
Filter Size
Sometimes, it is just a matter of your filter being undersized for your pump! Every filter has its own maximum gallons per minute (GPM) that it can handle, and every pump has a maximum GPM that it runs. If your pump GPM is higher than what your filter can handle, pressure will build up after the pump, flooding its way back into the pool. Always be sure your pump and motor are under the maximum GPM for your filter.
Blockages
Typically, a blockage after the pump is found by the process of elimination. If you’ve tried troubleshooting the filter, the gauge, and the possibility of leaks, it’s likely a blockage after the pump.
First, the easiest thing to check is your valves. If you open one up, are there a lot of leaves and other debris in it? Clean it out, and see if that improves your pressure! Then, if your valves are clear, they’re still going to play an important role in finding where that block is. Shut off all but one of your valves, and then run the pump. If your filter pressure doesn’t improve after that, you’ve found the line your blockage has made home. Then push through a drain line to clear it up!
Moreover, having diverter valves closed off obstructing your return lines can cause high pressure in a filter. This is also an easy fix, as you need to open the closed valve.
For more information on fixing high water pressure, take a look at this blog: https://www.inyopools.com/blog/reducing-high-pressure-pool-system/
Under Pressure?
Still having trouble finding out what’s causing your filter pressure to go haywire? Do you know what’s causing it, but nothing seems to fix it? If you have any kind of troubles with your system, and you don’t know what to do, feel free to contact us via chat, support tickets, or call in to 407-834-2200 for assistance!
Leave a Reply