Filter Pressure Gauge

How do you read the pressure gauge?

Hi. The pressure gauge on an above ground pool filter is used to determine the amount of water flow going back into the pool. This lets you know when the filter media needs cleaned.

The instruction manual for a sand filter will tell you to backwash the system before using it for the first time. This will clean out any dust that might be in the sand and avoid getting any of into your clean, fresh pool water. After your initial backwash and rinse you can then go to the filter position. You would at this time check your pressure gauge. This will be your clean operating pressure and when the gauge goes up ten pounds then you should backwash again.

A typical reading might be 8 lbs at clean pressure so you would backwash at 18lbs. That is, of course, if the pressure gauge is working correctly. They tend to freeze up and need replace on a regular basis so it may be possible your gauge is not telling you a thing.

I have never replaced a bad pressure gauge because I do not use them. The water coming out of the return fitting, back into the pool, tells me everything I need to know about my filter operation.

If I have a strong flow of water the filter is fine. If the flow is weak the media needs cleaned. This applies to all types of filters. A sand filter needs backwashed and a cartridge filter needs the element hosed off. If the return flow is full of air bubbles then I know to look for an air leak on the suction side of the pump. The usual cause of this would be air getting in under the hair and lint pot lid.

Help With Pressure Gauge

by Bonnie
(md)

I have a Hayward de filter #50 that I need to replace the pressure gauge. I have unscrewed the large brown casing from the filter but I can't get the gauge out. Is it screwed in or pressed in? Please help
Thanks Bonnie



Hi Bonnie. The gauge is screwed in and takes a wrench to remove it. There should be a part that looks like a nut at the top of the threads. It should unscrew without to much effort. The threads on the gauge should have Teflon tape on them, they should never be glued in.

I never change a pressure gauge myself. I leave them in place when they go bad. I can tell how my filter is doing by looking at the return flow going back into the pool. If the flow is strong the filter is fine. As the flow of water slows down the filter needs cleaned. All the filter gauge is telling you is what you can visually see for yourself by looking at the water going back into your pool.