What Should the Pool Filter Pressure Gauge Read?

[Hank]

We have a new inground pool with an in-floor cleaning system, spa fountain, and waterfall. As the system cycles through the various cleaning zone, the filter (4 cartridges) pressure gauge varies from 30 to 38 pounds. I've been told that it ought to be 10-15 psi. Is this correct? The filter cartridges are new. Do I have a problem with the piping?

Thank You,

Hank in Bradenton, FL

[Sunbuilt Pools]

Filter Pressure is a result of several elements of the mechanics in the pool. These include pump flow, filter flow rate, pipe size, number of returns, size of the return opening , number of elbows, and other equipment such as heaters and chlorinators. The pump sucks water from the pool and then pushes the water through all the elements listed above. Each element creates a degree of backpressure which cause pressure in the pipe measured by pounds per square inch. A way to see the effects is look at the pressure and then take out the return eyeballs and the pressure drops. Pressure is needed so the pool returns can shoot water out and provide better circulation of water. Ideally your pressure sits somewhere between 15-20 PSI so there is good circulation without too much pressure on pipe fittings and equipment. However it is common for pressure gauges exposed to teh elements to fail and read wrong. Some people replace their gauges yearly, others learn to use them with the new readings. Most manufacturers suggest cleaning or backwashing the filter when pressure is 10 PSI higher then normal. Note that a high backpressure can reduce teh efficiency of the filter as well.

[Hank]

Ideally your pressure sits somewhere between 15-20 PSI so there is good circulation without too much pressure on pipe fittings and equipment. However it is common for pressure gauges exposed to teh elements to fail and read wrong. Some people replace their gauges yearly, others learn to use them with the new readings. Most manufacturers suggest cleaning or backwashing the filter when pressure is 10 PSI higher then normal. Note that a high backpressure can reduce teh efficiency of the filter as well.

Since the pool is only one month old, and the guage was replaced just in case it was bad (it wasn't), then it seems that that pressure is too high. You mentioned that 15-20 PSI would be ideal. My pool is at 30-40 PSI, depending on whether I bypass the heater or not. So I guess you are saying that the pressure is not normal for a new pool.

[Lew Akins]

QUOTE(Hank @ Sep 28 2005, 05:44 PM) 1355[/snapback]

We have a new inground pool with an in-floor cleaning system, spa fountain, and waterfall. As the system cycles through the various cleaning zone, the filter (4 cartridges) pressure gauge varies from 30 to 38 pounds. I've been told that it ought to be 10-15 psi. Is this correct? The filter cartridges are new. Do I have a problem with the piping?

Thank You,

Hank in Bradenton, FL

Hank, There is no such thing as "normal pressure". As resistance to flow increases, the pressure goes up. When operating a spa, the pressure will normally be higher than typical pool operation. This is because the orfice size in spa jets are smaller. We give up volume for velocity. The same is true with your in-floor cleaner. They will ALWAYS run at a higher pressure than a standard return system.

[BoatingDave]

<!--quoteo(post=1355:date=Sep 28 2005, 05:44 PM:name=Hank)--><div class='quotetop'>QUOTE(Hank @ Sep 28 2005, 05:44 PM) 1355[/snapback]</div><div class='quotemain'><!--quotec-->

We have a new inground pool with an in-floor cleaning system, spa fountain, and waterfall. As the system cycles through the various cleaning zone, the filter (4 cartridges) pressure gauge varies from 30 to 38 pounds. I've been told that it ought to be 10-15 psi. Is this correct? The filter cartridges are new. Do I have a problem with the piping?

Thank You,

Hank in Bradenton, FL

<!--QuoteEnd--></div><!--QuoteEEnd-->

Hank, There is no such thing as "normal pressure". As resistance to flow increases, the pressure goes up. When operating a spa, the pressure will normally be higher than typical pool operation. This is because the orfice size in spa jets are smaller. We give up volume for velocity. The same is true with your in-floor cleaner. They will ALWAYS run at a higher pressure than a standard return system.

Every pool has a "usual" pressure depending on how the pipes were laid and what features are used in the system. Also recognize that where you take the measurement in the system may change your reading. I am assuming that you are measuring the pressure at the main filter. Realize that if flow is restricted to the main filter, the pressure guage on the main filter actually may drop. (for example if the final trap at your main filter pump becomes clogged with leaves, less flow will get into your main filter and hence less pressure will be noted on the guage). cleaning the filter trap will cause the pressure reading to go back into the "usual" range.