Clean Filter Pressure Drop / Cold Snap ?

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parkinsmith

Gold Supporter
Apr 30, 2021
205
Clifton Texas, Lake Whitney
I am a new pool owner. The pool is two months old. This is our first time dealing with a cold front that came in last night . We are in Central Tx. We had cold temps last night, in the mid to low 30's and I noticed this AM for the first time that my clean pressure on the filter gage dropped from 20 to 15 . What does this mean and can it be due to the cold if not what ? What do I need to do about this ?

Also we are unsure what we need to do with our pump or settings for these cold nights. We were swimming on Thursday. This cold snap was unexpected. As we are in Texas we will keep the pool open for winter / we have a heater . Just not sure what to do to keep the equipment and pipes safe? I like to run the pump 24/7 not sure what I should run it at in the winter ( it was set at 80% ).

Would appreciate any feedback and insight.
 
Sometimes a drop in pressure indicates a clog in the impeller of the pump as the pump is not putting out fully. Check the pump basket if it is full of debris as well. Also, with a variable speed pump, you have to ensure you check pressure at the same speed as a lower rpm will also indicate a lower filter pressure.

Do you have your VS pump to run at different speeds throughout the day? The pump is more energy efficient if you can run it at a low rpm for most of the day but still operate the SWCG, then only increase rpm for several hours to either skimming action or running a cleaner.

When you say "it was set at 80%", is that the pump or the SWCG? If you are testing your FC every couple of days, you should see your demand for FC decline so your SWCG should be turned down since you are running your pump 24 hrs.

With regard to cooler temperatures, your automation should have a freeze protection setting that ensure the pump runs when air temperatures reach a set value - such as 38 deg F. But if you are running your pump 24/7 then that won't matter.
 
If you are running 24/7 then there should not be an issue with freezing unless it is in part of the plumbing that does not get constant flow. The only issue, and this was a big problem last year, is that if the power goes out, then the equipment might freeze. So, for those low temperature periods where you have some warning and it looks like it will be very cold for a long period of time (> 8hrs), it is usually best to just drain the pad equipment of water. This can easily be done using the air purge valve on top of the filter if you have one. Here is a pretty in depth discussion on freeze protection and some of the alternatives:

The Physics of Freezing and Freeze Protection

Recently, there have been a lot of questions from those living in moderate climates about using automatic freeze protection or running pumps to prevent freezing and what a pool owner should do when temperatures drop so I thought it might be useful to have a thread which dealt with the issue from...
www.troublefreepool.com www.troublefreepool.com

As for the change in filter pressure, when filter pressure drops, that is usually an indication of a suction side restriction of some sort. However, freezing temps can also affect pressure gauges. When you shut off the pump does the gauge go to zero?
 
HermanTX said:
Sometimes a drop in pressure indicates a clog in the impeller of the pump as the pump is not putting out fully. Check the pump basket if it is full of debris as well. Also, with a variable speed pump, you have to ensure you check pressure at the same speed as a lower rpm will also indicate a lower filter pressure.

Do you have your VS pump to run at different speeds throughout the day? The pump is more energy efficient if you can run it at a low rpm for most of the day but still operate the SWCG, then only increase rpm for several hours to either skimming action or running a cleaner.

When you say "it was set at 80%", is that the pump or the SWCG? If you are testing your FC every couple of days, you should see your demand for FC decline so your SWCG should be turned down since you are running your pump 24 hrs.

With regard to cooler temperatures, your automation should have a freeze protection setting that ensure the pump runs when air temperatures reach a set value - such as 38 deg F. But if you are running your pump 24/7 then that won't matter.
Click to expand...
Thanks for the info , a few questions .

Also, with a variable speed pump, you have to ensure you check pressure at the same speed as a lower rpm will also indicate a lower filter pressure. What do you mean by this?
The PB set this all up at start up showed me my clean pressure is to be 20 . So are you saying I need to get what the pressure would be if I set at lower the speed? I have not yet changed the speed. The PB set the filter/pump at 80 % running 24/7 ( that is what is says on the pro logic automation) if I want to decrease pump speed they said to just go into the menu and hit the arrow up or down to adjust the pump speed. The issue is I have no idea how any of these percentages correspond with the actual RPM.

Do you have your VS pump to run at different speeds throughout the day? It is not set this way yet but I plan to do so. The pump is more energy efficient if you can run it at a low rpm for most of the day but still operate the SWCG, then only increase rpm for several hours to either skimming action or running a cleaner.

When you say "it was set at 80%", is that the pump or the SWCG? No the SWG is set at 25% . Do you know if the SWG will turn itself off when temps get too cold for it run? The 80% is what automation says the filter speed is . It does not provide RPM info on the pro logic panel

With regard to the current lower filter pressure, can this be affected by the first cold snap? If not do I need to have it looked at for a clog ? It is just odd this happened the morning after the almost freezing temps. I did look at it yesterday and it was fine .
 
parkinsmith said:
The PB set this all up at start up showed me my clean pressure is to be 20 . So are you saying I need to get what the pressure would be if I set at lower the speed? I have not yet changed the speed. The PB set the filter/pump at 80 % running 24/7 ( that is what is says on the pro logic automation) if I want to decrease pump speed they said to just go into the menu and hit the arrow up or down to adjust the pump speed. The issue is I have no idea how any of these percentages correspond with the actual RPM.
Click to expand...
If your current pump speed is set at 80% then if it was to be set at 60%, the filter pressure would decline slightly because of the change in speed. That does not seem to be your issue because you have your pump set at a constant speed of 80%. You are not reaping any advantages of a VS pump if you only set it at 1 speed. Your PB did not help you on this and I agree with your plan to adjust your pump to run at different speeds throughout the day. I am not familiar with your Pro Logic Automation so maybe someone will chime in to help you, or you can post another question specifically on that to get help.

parkinsmith said:
No the SWG is set at 25% . Do you know if the SWG will turn itself off when temps get too cold for it run? The 80% is what automation says the filter speed is . It does not provide RPM info on the pro logic panel
Click to expand...
Most SWCG's do not operate at water temperatures below 55 deg F. Each SWCG is a little different on exact temperature.
At that time, it is best to turn your SWCG to 0% and just use liquid chlorine to sanitize your pool.
parkinsmith said:
With regard to the current lower filter pressure, can this be affected by the first cold snap? If not do I need to have it looked at for a clog ? It is just odd this happened the morning after the almost freezing temps. I did look at it yesterday and it was fine .
Click to expand...
It could be the cooler temperatures that affected the gauge slightly. If you turn off the pump, does the gauge read ZERO or is it slightly above zero?
 
mas985 said:
If you are running 24/7 then there should not be an issue with freezing unless it is in part of the plumbing that does not get constant flow. The only issue, and this was a big problem last year, is that if the power goes out, then the equipment might freeze. So, for those low temperature periods where you have some warning and it looks like it will be very cold for a long period of time (> 8hrs), it is usually best to just drain the pad equipment of water. This can easily be done using the air purge valve on top of the filter if you have one. Here is a pretty in depth discussion on freeze protection and some of the alternatives:

The Physics of Freezing and Freeze Protection

Recently, there have been a lot of questions from those living in moderate climates about using automatic freeze protection or running pumps to prevent freezing and what a pool owner should do when temperatures drop so I thought it might be useful to have a thread which dealt with the issue from...
www.troublefreepool.com www.troublefreepool.com

As for the change in filter pressure, when filter pressure drops, that is usually an indication of a suction side restriction of some sort. However, freezing temps can also affect pressure gauges. When you shut off the pump does the gauge go to zero?
Click to expand...
Thanks for all the info , yes when I turn off the pump it goes to zero , when I turn it back on it goes back to around 15 , normal is 20. This happened after the cold last night .
 
Try tapping the gauge and see if it jumps up.

Also, as things warm up, see if the pressure changes in case it was ice. However, when I look at Clifton/Whitney temperature history, it doesn't show freezing temps for last night. Are you going by the ProLogic measurement?

A suction side restriction is still possible but if not ice, it would need to coincide with some other event such as vacuuming a lot of debris which is clogging the suction lines.
 
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HermanTX said:
If your current pump speed is set at 80% then if it was to be set at 60%, the filter pressure would decline slightly because of the change in speed. That does not seem to be your issue because you have your pump set at a constant speed of 80%. You are not reaping any advantages of a VS pump if you only set it at 1 speed. Your PB did not help you on this and I agree with your plan to adjust your pump to run at different speeds throughout the day. I am not familiar with your Pro Logic Automation so maybe someone will chime in to help you, or you can post another question specifically on that to get help.


Most SWCG's do not operate at water temperatures below 55 deg F. Each SWCG is a little different on exact temperature.
At that time, it is best to turn your SWCG to 0% and just use liquid chlorine to sanitize your pool.

It could be the cooler temperatures that affected the gauge slightly. If you turn off the pump, does the gauge read ZERO or is it slightly above zero?
Click to expand...

mas985 said:
Try tapping the gauge and see if it jumps up.

Also, as things warm up, see if the pressure changes in case it was ice. However, when I look at Clifton/Whitney temperature history, it doesn't show freezing temps for last night. Are you going by the ProLogic measurement?

A suction side restriction is still possible but if not ice, it would need to coincide with some other event such as vacuuming a lot of debris which is clogging the suction lines.
Click to expand...
Thanks , no vacuuming but there are hundreds of tiny sticks that have fallen from trees with the leaves. I have been running my Dolphin robot every day and it gets clogged by the sticks mixing with the leaves. I have to clear all that stuff from it every 30 min . Could this stuff also cause a clog with the filter ? I stay on top of pool clearing daily so I am not sure how much is finding its way through the filter. Best way to check for clogs? .
 
That debris may have gotten stuck in the pump's impeller. Clean out pump basket and impeller inlet at the bottom. If that doesn't work, you may have to pull the motor from the wet end to inspect the impeller.
 
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