New build cartridge filter and GPM issues

Jump to latest Follow Reply
M

mvoltin

0
Silver Supporter
Aug 1, 2016
67
atlanta, GA
Just started the new pool (13,000gallons) and have two unusual issues that could possibly be related any advice on troubleshooting will be appreciated:

The cartridge filter is Pentair 160353 (200sf) with water coming out from the release valve as it supposed to and pressure gauge showing 10 during prime (max RPM). When RPM drops to 1400 then pressure drops to zero and water no longer comes out of the release valve. When I close it and open it, air comes out briefly (pressure was slowly building up when it was closed). So, it almost seems that cartridge is not providing enough resistance at low RPM to build the pressure and water just flowing through the filter? Is that a possible explanation and should i be comfortable with zero pressure and no water coming out of release valve during normal RPM? When taking out the cartridge, I can see that it is catching stuff, so, it's working but not sure if there is any place where water "escapes" too quickly towards outlet that prevents pressure build-up?

two caveats:
  1. I purchased the filter at a warehouse about 4 years ago. So, it was standing outside for 4 years before being plugged in. the cartridge looks fine..
  2. When looking closely, the cartridge itself is 150sf inside the 200sf filter casing - the size is the same and fits as it is supposed to. I am guessing the difference is number of folds on the cartridge and that should not make a difference in how much pressure builds, right?

Here is the second issue that may or may not be related to this:

I have H2 FlowVis flow meter that is supposed to be on of the best. it shows 150GPM when priming at full speed (Superflo VS) and then around 45GPM at 1400RPM. both of these flows seem wrong - Supeflow cannot go to 150GPM (110 max) based on its flow chart and people usually get around 15GPM at 1400RPM. I am contacting the company to see what's going on but wanted to point this out here as well. So, basically, I have zero pressure in my filter at 45GPM and 10 PSI at 150GPM.
 
The pressure gauge loses 1 psi for every 2.31 feet above the surface of the water.

For example if the pressure was 2 psi and you raised the gauge by 7 feet, the pressure at the gauge would be -1.

So, it is possible for the pressure at the gauge to be negative while the pump is on low speed.

The flow meter is probably defective and the top part should be replaced.
 
M,

Filter pressure is backwards from what you think.. Low pressure is better than high pressure.. The filter gauge is really reading how much effort it takes to force water through the filter.. The more back pressure, the less the flow will be.

What actual "problem" does your pool have??? Do you have poor flow coming out of your pool returns? What is not working?

Thanks,

Jim R.
 
T
Jimrahbe said:
M,

Filter pressure is backwards from what you think.. Low pressure is better than high pressure.. The filter gauge is really reading how much effort it takes to force water through the filter.. The more back pressure, the less the flow will be.

What actual "problem" does your pool have??? Do you have poor flow coming out of your pool returns? What is not working?

Thanks,

Jim R.
Click to expand...
Thanks. The filter inlet is about 4 feet above pool water surface. Water is flowing great, with no air bubbles, etc. My perceived "problems" are:
  1. Pressure gauge showing zero since every reference states that pressure gauge is the primary indicator of filter operation and it should be zero if the flow is off. I just started the pool and wanted to make sure there was nothing wrong.
  2. Unless at high speed, water is not coming out of air release valve. I actually noticed that at low speed there is slight negative pressure at the release valve (when I put a finger on it, i feel slight suction). This could be the case when water is flowing through with virtually no resistance, it would create slight "suction" effect... Not sure, just speculating and it just doesn't seem normal. All the references say to get the air out and I actually have air going in at lower speeds.
  3. The pool is not clearing up as fast as I would think - this is totally subjective but maybe I need to be more patient (it's only the second day). This is why i am wondering if water somehow bypassing the cartridge (hence no pressure); although there is no tear in the cartridge and it seems fully seated.'
  4. Another concern is that, if I build an air inside the filter housing at low speed, will that be a problem when I increase the speed to the max? I thought air inside the filter was a big "no"
 
1 - the lower the pump rpm, the lower the pressure on the gauge

2 - only bleed the filter at higher rpm. Once its bled, no air will build up in the filter unless you have a suction side air leak or an airleak when the pump is off.

3 - if the pool isn't clearing up, you most likely have a chemical issue and not a filtering issue. What does your pool water look like? Provide a full set of current test results from one of the recommeded test kits.

FC
CC
pH
TA
CH
CYA
Water temp

4 - bleed at high speed. No air should accumilate inside the filter unless you have air leaks.
 
  • Like
Reactions: Jimrahbe
mvoltin said:
The filter inlet is about 4 feet above pool water surface.
Click to expand...
The height of the gauge above the surface of the water reduces the gauge reading by 1 psi for every 2.31 feet.

The gauge pressure when the pump is off for most pools is negative.

If your gauge is 6.9 feet above the surface of the water, the pressure when the pump is off is -3 psi if the filter is completely full of water.

So, your starting pressure is -3 psi and if the pump provides 2 psi, the gauge will read zero unless you have a gauge that also shows vacuum. If you have a compound gauge, the reading would be -1 psi if the filter is full of water or the water in the filter would be 2.31 feet below the gauge if the air bleed is open and the pressure is zero unless you bleed off all air.

Compound Pressure Vacuum Gauge Bottom Mount No Lead | Best Aquatic Management | Pool Management

Compound Pressure Vacuum Gauge Bottom Mount No Lead
bestaquatic.com bestaquatic.com

When the pump first primes, bleed off all air before going to low speed or the water won't completely fill the filter and water will only go through the bottom part of the filter.
 
Last edited:
mvoltin said:
Unless at high speed, water is not coming out of air release valve. I actually noticed that at low speed there is slight negative pressure at the release valve (when I put a finger on it, i feel slight suction). This could be the case when water is flowing through with virtually no resistance, it would create slight "suction" effect... Not sure, just speculating and it just doesn't seem normal. All the references say to get the air out and I actually have air going in at lower speeds.
Click to expand...
It sounds like your air release valve is broken and leaking. It should not have water coming out or air going in at any speed during normal operation.
 

Enjoying this content?

Support TFP with a donation.

Give Support
proavia said:
1 - the lower the pump rpm, the lower the pressure on the gauge

2 - only bleed the filter at higher rpm. Once its bled, no air will build up in the filter unless you have a suction side air leak or an airleak when the pump is off.

3 - if the pool isn't clearing up, you most likely have a chemical issue and not a filtering issue. What does your pool water look like? Provide a full set of current test results from one of the recommeded test kits.

FC
CC
pH
TA
CH
CYA
Water temp

4 - bleed at high speed. No air should accumilate inside the filter unless you have air leaks.
Click to expand...
Thank you. Based on everybody's input here, there is no issue with the filter.

I just plastered it with DiamondBrite and second day circulating water. So, chemistry is still messed up - following the start-up instructions now: first focusing on alkalinity and PH. Will start hardiness tomorrow and then chlorine. Don't have full panel yet but alkalinity is 90 and Ph 7.2. Interestingly, chlorine is 1 (tested at Leslie's pool supply store) and couldn't figure out where it came from since I have not added any chlorine and tap water, that I used to fill the pool, shouldn't have that much chlorine.
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply